Long term evolution

LTE RPESS
Radio Planning Essentials
Soc Classification level
1 © Nokia Siemens Networks Presentation / Author / Date
Radio Planning Essentials
Contents
Days 1 and 2
• LTE Overview
• LTE Architecture
– Network Elements and Interfaces
• Air Interface
– Technologies: OFDMA/SC-FDMA
– Physical Layer
Structure and Channels
Procedures
– L2/L3
• LTE NSN Solution
– Release Roadmap
– SON: Overview, ANR & Cell ID
Management
– Bearer Management (QoS) and VoIP
over LTE
– LTE RRM (Features)
• LTE Performance
• LTE Radio Planning
Soc Classification level
2 © Nokia Siemens Networks Presentation / Author / Date
– L2/L3
– Connection Management
– Mobility Management
• TD-LTE Overview
• Appendix DL/UL Signal Generation
• LTE Radio Planning
– Dimensioning
Link Budget
Dimensioning Tool (and exercise)
LTE 6 sectors vs. 3 sectors
LTE Rural at 800MHz (DD)
How to improve the LiBu?
• Coverage Criteria for Field Measurements
Useful Links
• Roadmaps
– https://sharenet-
ims.inside.nokiasiemensnetworks.com/livelink/livelink?func=ll&objId=364977916&objActio
n=Browse
• Latest version of the Dimensioning Tool
– https://sharenet-ims.inside.nokiasiemensnetworks.com/Overview/D428552449
• Air interface Dimensioning Guideline
Soc Classification level
3 © Nokia Siemens Networks Presentation / Author / Date
• Air interface Dimensioning Guideline
– https://sharenet-ims.inside.nokiasiemensnetworks.com/Open/426856094
• Working Instructions for the Dimensioning Tool
– https://sharenet-ims.inside.nokiasiemensnetworks.com/Download/397804934
• NEI (Network Engineering Information) material (RL features)
– https://sharenet-ims.inside.nokiasiemensnetworks.com/Open/427213042
NSN LTE Solution
Soc Classification level
4 © Nokia Siemens Networks Presentation / Author / Date
NSN LTE Solution
LTE Release Roadmap
Soc Classification level
5 © Nokia Siemens Networks Presentation / Author / Date
LTE Release Roadmap
LTE FDD Release Roadmap (December 2010)
RL20
Ready for Contract
RL10
Available
RL30
Under Planning
RL40
Study Items
RRM / Telecom
Fair Scheduler
Open / Closed Loop UL Power Control
and DL Power Setting
Link Adaptation by AMC (UL/DL)
CQI Adaptation (DL)
Downlink Adaptive Open Loop MIMO for
Two Antennas
Inter RAT Cell Re-Selection
Redirect to LTE or Other Technology
Intra Frequency Handover via X2
O&M
SON -LTE BTS Auto Connectivity
SON -LTE BTS Auto Configuration
RRM / Telecom
Support of Multiple EPS Bearers
Support of GBR EPS Bearer
Service Differentiation for Non-GBR
EPS Bearer
Rate Capping
Intra LTE Handover via S1
Inter Frequency Handover
CS Fallback via Redirect
Emergency Call via CS Fallback
O&M
SON –ANR (Intra-, Inter Frequency)
Cell Outage Triggered Reset
Cell and Subscriber Trace
RRM / Telecom
Interference Aware Scheduling
DRX in RRC Connected Mode
Operator Specific QCI
Cell ID Based Location Services
Inter RAT Handover to WCDMA
NACC to GSM
Subscriber Profile Based Mobility
Load Dependent UL Power Control
SRVCC to WCDMA / GSM
Emergency Call
O&M
SON -ANR Fully UE Based
SON -ANR InterRAT
RRM / Telecom
Channel Aware Scheduler (UL)
Smart DRX
GBR QoS Package
TTI Bundling
Load Based Handover
OTDOA Location Service
CB Fallback Enhancements
O&M
SON -Optimization of InterRAT
Neighbours
Mobility Robustness Optimization (MRO)
II
SON -Minimization of Drive Tests (MDT)
Soc Classification level
6 © Nokia Siemens Networks
SON -NetAct Optimizer LTE
SON -Central ANR
SON -Self Healing
Security
BTS Site Solutions
Feederless Flexi LTE BTS Site
Frequency: 800, 1.7/2.1, 2100, 2600MHz
Bandwidth: 5, 10 and 20 MHz
Transport
Flexi Transport Sub-Modules: FTIB, FTLB
Traffic Prioritization on IP Layer
Traffic Prioritization on Ethernet Layer
VLAN Based Traffic Differentiation
Traffic Shaping
IPSec Support
Cell and Subscriber Trace
BTS Site Solutions
RF Sharing GSM- LTE
Frequency: 1600, 1800 MHz
Bandwidth: 15 MHz
Transport
QoS Aware Ethernet Switching
Ethernet OAM
Flexi Packet Radio Connectivity
SON -Synchronization of InterRAT
Neighbors
SON -Optimization Neighbor Relations
SON -Mobility Robustness (MRO)
BTS Site Solutions
RF Sharing WCDMA - LTE
Distributed Site
180W Flexi Multiradio Remote RF
Frequency: 700, 850, 900, 1900 MHz
Transport
CESoPSN
Fast IP Rerouting
Ethernet Jumbo Frames
BTS Power Saving Mode
BTS Site Solutions
Flexi Multiradio System Module
LTE Dual Band Operation
Flexi Lite BTS
4TX/4RX RRH
System Sharing WCDMA – LTE
4-way RX Diversity (MRC)
Transport
IPv4/IPv6 Dual Stack
Transport Separation for RAN Sharing
Planned Milestones for RL (FDD) Releases
•RL10
2010 2011 2012
RL09
C5 10/10
CP 5/10
•RL20
CP 12/10
C5 Q1/11
CP 2Q/11
2009
Soc Classification level
7 © Nokia Siemens Networks
•RL30
Milestones in italics are initial estimates
CP: limited commercial availability
C5: full commercial availability
C5 3Q/11
•RL40
CP 2Q/11
C5 Q1/12
CP Q4/11
Radio Enhancements of RL20 on top of RL10
• Further SON functionalities
– ANR Intra and Inter frequency
• Enhances the LTE QoS (Quality of
Service)
– GBR (Guaranteed Bit Rate) and
differentiation of 5 non-GBR bearer
classes
– Multiple bearer for simultaneous
service usage from one UE
• Enhances mobility solutions
– Intra LTE Handover via S1
– Inter Frequency Handover
• RL20 extends the supported
deployment solutions and
frequency variants
– 1800MHz (3GPP band 3) with Flexi
Multiradio Triple RF Module FXEA
Soc Classification level
8 © Nokia Siemens Networks Presentation / Author / Date
service usage from one UE
(user equipment)
• First steps towards VoLTE (Voice
over LTE) operation
– VoLTE support with GBR, bearer
prioritization; also CS fallback
Multiradio Triple RF Module FXEA
– RF Sharing GSM - LTE: concurrent
mode operation of radio modules
Radio Enhancements of RL30 on top of RL20
• Further SON functionalities
– ANR Fully UE based and Inter-RAT
ANR features
– Mobility Robustness (MRO)
– Optimization of Neighbour Relations
• Enhanced user experience
– Smart Scheduler (Interference Aware)
– Higher UL peak rates due to ’increased
• Additional deployment solutions
– Support of 6 sectors with one System
Module
– Distributed Sites: up to 20km between
RF module and system module with
optical fibre
• Additional frequency variants
• 760, 850, 900 and 1900 MHz RF
Soc Classification level
9 © Nokia Siemens Networks Presentation / Author / Date
– Higher UL peak rates due to ’increased
uplink MCS range’
– Extended battery life through
discontinuous Rx: >90% reduction in
power consumption
• Enhances mobility solutions
– Inter RAT Handover to WCDMA
– NACC (network assisted cell change) to
GSM
• 760, 850, 900 and 1900 MHz RF
modules
• 730, 210 and 2600 MHz RRH
SON: Overview, PCI Management and ANR
Soc Classification level
10 © Nokia Siemens Networks Presentation / Author / Date
SON: Overview, PCI Management and ANR
SON: Self-organising networks
Overview
• Standards for SON are developed by NGMN (Next Generation Mobile Networks)
and standardized by 3GPP
– http://www.ngmn.org/
– 3GPP TS36.902 describes the SON user cases and solutions
– 3GPP TS32.500: SON concepts and requirements
– 3GPP TS32.501-2 Self establishment (use case)
– 3GPP TS32.511 Automatic Neighbour Relation –ANR- (use case)
Soc Classification level
11 © Nokia Siemens Networks Presentation / Author / Date
• The idea behind the SON concept is to reduce operational efforts and
the complexity of LTE networks
– Complex networks e.g. due to parallel operation of LTE with 2G/3G and multi
vendor scenarios
– Unclear and proprietary operational and maintenance specifications
• How? By introducing self configuring and self optimising mechanisms that
increase the network performance and quality and, at the same time, decrease
maintenance costs including reduction in human interaction
Main Functionalities of SON
Self-configuration (Plug and Play):
• Automated network integration of new eNB
by auto connection and auto configuration
• Simplified installation, faster roll out
• Automated neighbour configuration (X2)
• Physical Cell ID
Self-optimization (Auto Tune):
• Auto-tune the network (coverage and
Self-healing (Auto Repair):
• Automatic detection and localization and
removal of failures:
• HW/SW-Failure Mitigation
• Cell Outage Detection and Outage Mitigation
• Automatic Alarm Reaction
Self-planning:
• Dynamic re-computation
Soc Classification level
12 © Nokia Siemens Networks Presentation / Author / Date
• Auto-tune the network (coverage and
capacity) with the help of UE and eNB
measurements on local eNB level and/or
network management level
• Energy savings
• Mobility Robustness
• Load Balancing
• RACH Optimization
• Inter-cell interference coordination
• Dynamic re-computation
of network plan due to capacity extensions,
traffic monitoring or optimizations
• Often going along with self-optimization
(efficient way of network growth support)
• Automated configuration of
Physical Cell ID
• ANR
•
Rel. 8 Rel. 9 Rel. 10
2008 2009 2010 2007 2009 2010 2008
3GPP: SON in standardization
• Interference Reduction
• Inter Cell Interference
Coordination
• Coverage and Capacity
• Remaining/spill over(s) Rel. 8
• Automated configuration of
Physical Cell ID
• Inter RAT ANR
SON in 3GPP
Soc Classification level
13 © Nokia Siemens Networks Presentation / Author / Date
• Self-configuration of eNBs
• Automatic Software Management
Self Healing
Self Configuration
Self Optimization
RAN3
SA5
• Coverage and Capacity
optimization (spill over,
new features like relays)
• Mobility Robustness optimization
(spill over,
new features like relays)
• Energy Savings
• Control and Resource
optimization of Relays
• Self Healing
• Inter RAT ANR
• Automatic Radio Configuration
Function
• Coverage and Capacity
optimization
• Mobility Load Balancing
• Mobility Robustness optimization
• Avoidance of Drive Tests
• SON Evaluation Scenario
• Cell outage compensation/
mitigation
Physical Cell identification and Global Cell ID
identification
Physical Layer Cell ID (PCI)
• The sequence to generate the Reference Signal depends
upon the PCI
• Short repetition cycle of 1 ms
• Limited to 504 values so not unique
• Careful assignment needed because a UE shall never
receive the same value from 2 different cells
Soc Classification level
14 © Nokia Siemens Networks Presentation / Author / Date
Global Cell ID (ECGI)
•
receive the same value from 2 different cells
• E-UTRAN Cell Global identifier
• Part of SIB 1
• SIB 1 is sent once every 20ms
• Unique in the network: constructed from MCC, MNC en E-UTRAN Cell Identifier
PCI management
• Each cell of a LTE network needs to have a Physical Cell ID (PCI) assigned
• Since the PCI range is limited to 504 values neither the neighbours of a cell, nor
the neighbours of the neighbours shall have the same PCI value
• Handling phases:
1) Central optimized assignment for initial PID assignment for Flexi Multiradio
BTS via NetAct Optimizer
• PCI assigned based on distance and actual adjacencies
RL10
Automated PCI assignment and collision detection
Soc Classification level
15 © Nokia Siemens Networks Presentation / Author / Date
• PCI assigned based on distance and actual adjacencies
2) Collision Detection with alarming in Flexi Multiradio BTS
• Collision: two neighbour cells with the same PCI
• During the X2 setup the neighbour information is exchanged, Flexi Multiradio
compares its own PCI with the ones of the neighbours activating an alarm if
collision
3) Automatic Collision Resolution via NetAct Optimizer
• If collisions detected (via alarm) then optimization can be manually or automatically
triggered several times a day
Feature ID: LTE468
Automated neighbor relation (ANR) configuration
• Neighbour relations are important as wrong neighbour definitions cause HO
failures and dropped calls
• Self configuration of relations avoids manual planning & maintenance
ANR covers 4 steps:
1) Neighbour cell discovery
2) Neighbour Site’s X2 transport configuration discovery (i.e. Neighbour Site IP@)
3) X2 Connection Set-up with neighbour cell configuration update
4) ANR Optimization
Soc Classification level
16 © Nokia Siemens Networks Presentation / Author / Date
4) ANR Optimization
• The scope within ANR is to establish an X2 connection between source and
target nodes and for that it is necessary that source eNB knows the target eNB
IP@
• How the source eNB gets the IP@ differentiates the ANR features:
– Central ANR (RL10)
– ANR (RL20)
– ANR- Fully UE based (RL30)
MME
3GPP ANR configuration principle
Site
eNB - A
Neighbor
Site
eNB - B
New cell
discovered
New cell
identified
by ECGI
UE
connected
S1 : Request X2 Transport Configuration (ECGI)
relays
Soc Classification level
17 © Nokia Siemens Networks Presentation / Author / Date
CM
X2 Setup : IPsec, SCTP, X2-AP [site & cell info]
S1: Request X2 Transport Configuration
relays
request
S1: Respond X2 Transport Configuration (IP@)
S1 : Respond X2 Transport Configuration (IP@)
CM
relays
response
Add Site & Cell
parameter of
eNB-A
CM CM
Add Site & Cell
Parameter of
eNB-B
Neighbor Cell Tables in both eNB updated
ANR - Fully UE based
Automated planning: NO configuration of any neighbor cell attributes, no
OAM needed
• Fully 3GPP compliant
• UE triggers X2 establishment first when unknown PCI is
measured
• UE is asked to measure ECGI by source eNB
• Source eNB sends ECGI to MME
eNBID#A
eNBID#B
RL30
Soc Classification level
18 © Nokia Siemens Networks Presentation / Author / Date
• MME requests IP connectivity information (IP@) to the
target eNB
• MME forwards the target eNB IP@ to the source eNB
•Source eNB established a X2 connection to the target
neighbour sites
• X2-set up message used for exchange of all required
neighbour information
Advantage
• No manual neighbour planning
• requires SON/ANR supporting UE (report ECGIs)
S1-Interface
eNBID#A
eNBID#B
MME
X2-Interface
S1-Interface
Feature ID: LTE782
PCI: Physical Cell ID
ECGI: E-UTRAN Cell Global
Identifier
Central ANR (Automatic Neighbour Cell Relation)
Self Configuration of Neighbour Relations for LTE
• UE measurements are not taken into
account
• Central solution purely based in O&M:
NetAct Configurator and NetAct Optimizer
• Optimizer creates neighbours for each
site, then Configurator adds the IP@ to the
RL10
Soc Classification level
19 © Nokia Siemens Networks Presentation / Author / Date
list and this is downloaded to the sites with
the configuration data.
- Neighbour relations (X2 paths) are
already established as part of the
configuration
- UE measurements are ignored: if UE
detects an unknown neighbour (not part of
the neighbour list created by Optimizer) this
is ignored
Feature ID: LTE539
LTE ANR
Automated planning: NO configuration of any neighbor cell attributes
•NetAct Optimizer and Configurator create the list of potential neighbour cells and
related IP connectivity information
RL20
•When UE reports an unknown PCI the
source eNB looks for that PCI in look-up
tables to find the IP@ of the site hosting the
PCI reported
Soc Classification level
20 © Nokia Siemens Networks Presentation / Author / Date
Feature ID: LTE492
UEs measurements taken into account
to trigger the X2 connection
•Once known target eNB IP@ the X2
connection is established and information
between neighbours is exchanged
Advantage:
•Works with any UE (no need to report ECGI)
•No neighbour site planning required
Features supporting Inter-RAT ANR
• Automated planning of UTRAN/GSM
neighbours done via NetAct Configurator
and Optimizer
• 2G/3G relevant data for Inter RAT
relations is uploaded/retrieved from the
existing configuration management
NetAct
CM
Configurator
CM
Optimizer
Automated planning on central NMS level
RL30
Soc Classification level
21 © Nokia Siemens Networks Presentation / Author / Date
existing configuration management
database
• Optimizer calculates neighbour sites given
by geo-locations
• Configurator configures the neighbour cell
lists and downloads the plans
• No UE supporting UTRAN-ANR needed
LTE
GERAN
UTRAN
UTRAN
UTRAN/GERAN
Domain Managers
CM
GERAN
Features ID: LTE783 and LTE784
Synchronization of InterRAT neighbours
• Enhancement of Inter RAT ANR
previous features
• Update/synchronize automatically
changes of Inter-RAT neighbour
information in case of relevant
changes at the 2G/3G or LTE-side
ensuring up-to-date Inter RAT
neighbour relationships
• Changes to trigger update:
Always up to date neighbour relations
RL30
Soc Classification level
22 © Nokia Siemens Networks Presentation / Author / Date
• Changes to trigger update:
– Site/cells addition deletion
– Cell parameter changes
• Alignment to LTE network through
NetAct
• Synchronization processes can be
run automatically, be scheduled or
triggered manually by operator
Feature ID(s): LTE510
Optimization of neighbour relations
NetAct Optimizer (Intra-LTE)
Optimizer
PM
CM
Configurator
Automatic neighbour relationship evaluation. OPEX reduction in managing
neighbour relationships
• NetAct Optimizer supervises the quality of the
registered neighbour relations. Inefficient
neighbour relations may be blacklisted for HO
• Analysis based on HO performance
counters and configuration information
• Use cases:
RL30
Soc Classification level
23 © Nokia Siemens Networks
No HO
Feature ID(s): LTE 771
• Use cases:
• Neighbours will insufficient HO
performance can be blacklisted
• Blacklisted Neighbours can be
whitelisted (e.g. to re-evaluate the
performance due to changes in topology)
• Neighbours can be marked by an operator
so they are excluded from optimization.
• Optimization works in a mid to long term
schedule
SON - Mobility Robustness (MRO)
Increased network performance by automatic adaptations
• Optimizing the Intra-LTE (Intra-frequency) radio network HO-configuration
for robustness of mobility procedures (i.e. to avoid drops calls and radio link
failures due to too early/late HOs)
• MRO fine tunes based on long-running evaluation of KPIs / specific detections
in eNBs / influenced by operator policies
• Fine tuning refers to the adjustment of HO related thresholds like HO offsets
and Time to Trigger
RL30
Soc Classification level
24 © Nokia Siemens Networks
Feature ID(s): LTE 533
NetAct
PM-history
Height
Measuremant data Measurement data
MRO
-SF
MRO
-SF
Optimizer/Configurator
CM
PM
PM
Performance Measurements
CM
Bearer Management (QoS) and VoIP over
LTE
Soc Classification level
25 © Nokia Siemens Networks Presentation / Author / Date
Types of bearers
EPS: Evolved Packet System
PDN-GW: Packet Data Network Gateway
E-RAB: E-UTRAN Radio Access Bearer
Generated from
an E-RAB and
Generated
from a
combination
of Radio
Soc Classification level
26 © Nokia Siemens Networks Presentation / Author / Date
• EPS bearer provides user plane connectivity between UE and PDN-GW
– EPS carries user data between UE and PDN
• Radio bearers provide connectivity across the air interface. Two types:
– Signalling Radio Bearers (SRB) carry C-plane data (RRC and NAS messages) or
– Data Radio Bearers (DRB) carry U-plane data (user data/traffic)
an E-RAB and
S5/S8 bearer
of Radio
Bearer and
S1 bearer
Bearer Management
EPS Bearer
• There is always at least one EPS Bearer (default bearer) to provide always-
on IP connectivity:
– Created during the attach procedure
– It does not mean that there is a Data Radio Bearer established all the time
• Any additional EPS Bearer is called a dedicated bearer
• All user plane data transferred with the same EPS bearer has the same QoS
Soc Classification level
27 © Nokia Siemens Networks Presentation / Author / Date
• All user plane data transferred with the same EPS bearer has the same QoS
• Support for multiple EPS bearers is a pre-requisite for voice support
• Conversational Voice cannot be carried with just with non GBR bearers
Requires two bearers:
– QCI (QoS Class Identifier)=1 for user data
– QCI=5 for IMS signalling
Support of Multiple EPS Bearers
• It is possible to support up to 4 EPS bearers per UE
• The EPS bearers can have different QoS requirements (QCI) so multiple
services can be used at one UE
• Supported radio bearers combinations per UE and Flexi Multiradio BTS:
SRB1 + SRB2 + 2 x AM(*) DRB
SRB1 + SRB2 + 3 x AM DRB
SRB1 + SRB2 + 4 x AM DRB
Multiple sessions per UE
RL20
(*) AM: Acknowledged mode
Soc Classification level
28 © Nokia Siemens Networks Presentation / Author / Date
SRB1 + SRB2 + 4 x AM DRB
Feature ID(s): LTE7
SRB1: transfer RRC messages using
DCCH logical channel. Also NAS msg.
if SRB2 is not configured
SRB2: transfer RRC messages using
DCCH and which encapsulate a NAS
msg. SRB2 has lower priority that
SRB1
Service Differentiation for Non-GBR EPS Bearer
QCI (QoS Class Identifier) based service differentiation
• Differentiation of 5 different non-
GBR QCI classes with relative
scheduling weights
- QCIs: 5,6,7,8,9
• Support of different non-GBR
QoS classes
QCI Resource
Type
Priority Packet
Delay
Budget
Packet
Error
Loss
Rate
Example Services
1
GBR
2 100 ms 10
-2
Conversational Voice
2 4 150 ms 10
-3
Conversational Video (Live
Streaming)
3 3 50 ms 10
-3
Real Time Gaming
RL20
Soc Classification level
29 © Nokia Siemens Networks Presentation / Author / Date
QoS classes
• Flexi Multiradio allows to assign
relative scheduling weights for
each non GBR QCI on cell level
• The relative weight is
considered by the UL and DL
scheduler
• Default bearers are set up with
QCI 9 (for non-privileged users)
or QCI 8 (for premium users)
4 5 300 ms 10
-6
Non-Conversational Video (Buffered
Streaming)
5
Non-GBR
1 100 ms 10
-6
IMS Signalling
6
6 300 ms 10
-6
Video (Buffered Streaming)
TCP-based (e.g., www, e-mail, chat,
ftp, p2p file sharing, progressive
video, etc.)
7
7 100 ms 10
-3
Voice,
Video (Live Streaming)
Interactive Gaming
8
8 300 ms
10
-6 Video (Buffered Streaming)
TCP-based (e.g., www, e-mail, chat,
ftp, p2p file
sharing, progressive video, etc.)
9 9 300 ms 10
-6
Feature ID(s): LTE9
EPS Bearers for Conversational Voice
Support of GBR bearer with QCI=1
• Support of GBR QCI=1
• Needed to introduce high quality
voice services in LTE
• IMS based voice services
• Admission control enhancements
QCI Resourc
e Type
Priority Packet
Delay
Budget
Packet
Error
Loss
Rate
Example Services
1
GBR
2 100 ms 10
-2
Conversational Voice
2 4 150 ms 10
-3
Conversational Video (Live
Streaming)
3 3 50 ms 10
-3
Real Time Gaming
4 5 300 ms 10
-6
Non-Conversational Video (Buffered
RL20
Soc Classification level
30 © Nokia Siemens Networks Presentation / Author / Date
• Admission control enhancements
to handle GBR traffic
• RLC UM is applied for EPS
bearers with QCI=1
• Bearer combinations
• SRB1+SRB2+ …
• 1, 2, 3 or 4 x AM DRB + …
• 1 x UM DRB
Feature ID(s): LTE10
4 5 300 ms 10
-6
Non-Conversational Video (Buffered
Streaming)
5
Non-
GBR
1 100 ms 10
-6
IMS Signalling
6
6 300 ms 10
-6
Video (Buffered Streaming)
TCP-based (e.g., www, e-mail, chat,
ftp, p2p file sharing, progressive
video, etc.)
7
7 100 ms 10
-3
Voice,
Video (Live Streaming)
Interactive Gaming
8
8 300 ms
10
-6 Video (Buffered Streaming)
TCP-based (e.g., www, e-mail, chat,
ftp, p2p file
sharing, progressive video, etc.)
9 9 300 ms 10
-6
How to provide voice in LTE
VoLTE: Voice over LTE
• Driven by GSMA and currently widely preferred solution (vs. VoLGA: Voice over
LTE Generic access)
• Based on ‘One Voice’ initiative:
– To define the minimum mandatory set of functionality for interoperable IMS-based
voice and SMS over LTE
– IMS provides similar experience to 2G/3G voice supporting features like call waiting,
call hold, barring. Also allowing for the integration of voice with other features like
video content, instant messaging.
Soc Classification level
31 © Nokia Siemens Networks Presentation / Author / Date
http://www.gsmworld.com/our-work/mobile_broadband/VoLTE.htm
LTE Voice Evolution
VoIP
LTE
HSPA
I-HSPA
2G/3G
EPC
MSS
LTE broadband for
high speed data
Fast-Track VoLTE
IMS for enriched IP
multimedia services
LTE
HSPA
I-HSPA
NVS
LTE
HSPA
I-HSPA
2G/3G
EPC
MSS
EPC
VoIP
NVS
IMS
MSS: Mobile Softwitching solution
NVS: Nokia Siemens Networks Voice Server
IMS: IP Multimedia Subsystem
Soc Classification level
32 © Nokia Siemens Networks Presentation / Author / Date
• Simple upgrade of MSS
with NVS (VoIP) function
• Fully IMS compatible
reuse of CS infra-
structure for LTE VoIP
capable handsets
• SRVCC (HO LTE VoIP to
2G/3G CS)
• IMS-centric service
architecture
• Rich Communication
Services with full
multimedia telephony
• Support for any access
• SRVCC (HO LTE VoIP to
2G/3G VoIP)
• Main focus on LTE data
• CS Fallback to 2G/3G
CS access for voice
• Re-use existing MSC
Server system for voice
Evolution to IMS
VoIP solution
Introduce NVS
VoIP solution
CSFB to UTRAN or GSM via redirect
Voice on legacy networks
RL20
• Redirection from LTE to UTRAN or to
GSM during the call setup
• Both, MOC and MTC setup supported
• EPC must support CS inter-working for
mobility management and paging
• Redirection by RRC connection release
Soc Classification level
33 © Nokia Siemens Networks Presentation / Author / Date
• Required when there is no
Conversational Voice
support on LTE side
Feature ID(s): LTE562
CSFB: Call Setup Fallback
MOC: Mobile Originated Calls
MTC: Mobile Terminated Calls
IE: Information Element
• Redirection by RRC connection release
message with a RedirectedCarrierInfo IE
that enforces the UE to search for any cell
first at the highest priority UTRA carrier or
within BCCH carrier set for GSM
• Priorities for fallback layers are operator
configurable
• UE will camp back into the LTE carrier
after termination of the CS call
SRVCC to WCDMA/GSM
VoIP continuity to WCDMA/GSM
• Seamless handover for voice services to WCDMA/GSM when leaving LTE
coverage
• Voice services are handed over to the CS domain
• Non voice services are handed over to the PS domain in WCDMA. This is
not supported in GSM
• Procedure identical to LTE to WCDMA handover (i.e. same neighbour list,
thresholds and measurements)
RL40
Soc Classification level
34 © Nokia Siemens Networks Presentation / Author / Date
Feature ID(s): LTE872/873
thresholds and measurements)
• eNB triggers SRVCC only if UE has EPS bearer with QCI=1 established
and MME and UE are SRVCC capable
SRVCC: Seamless Radio Voice
Call Continuity
LTE RRM (Features)
Soc Classification level
35 © Nokia Siemens Networks Presentation / Author / Date
- Scheduler
- Link Adaptation (LA)
- CQI Adaptation (OLQC)
- Power Control (PC)
- Radio Admission Control (RAC)
- MIMO Mode Control
- Connection Mobility Control (CMC)
RRM building blocks and functions
Overview
Soc Classification level
36 © Nokia Siemens Networks Presentation / Author / Date
Scope of RRM:
• Management and optimized utilization
of the (scarce) radio resources:
• Increasing the overall radio network
capacity and optimizing quality
•Provision for each service/bearer/user
an adequate QoS (if applicable)
RRM located in eNodeB
LTE RRM
Scheduling
• Motivation
– Bad channel condition avoidance
Soc Classification level
37 © Nokia Siemens Networks Presentation / Author / Date
OFDMA
The part of total available
channel experiencing bad
channel condition (fading) can
be avoided during allocation
procedure.
CDMA
Single Carrier transmission
does not allow to allocate
only particular frequency
parts. Every fading gap
effects the data.
Scheduler (UL/DL)
• Cell-based scheduling (separate scheduler per cell)
• Resource assignment in time and frequency domain (UL/DL)
• Scheduling on TTI basis (1ms)
• Proportional fair resource assignment among UEs
• Priority for SRB (Signalling Radio Bearers) and HARQ re-transmissions over
DRB (Data Radio Bearers)
• Common channels (i.e. system info, random access and paging) have highest
priority
RL10
Soc Classification level
38 © Nokia Siemens Networks Presentation / Author / Date
priority
• Downlink:
• Channel aware DL scheduling (Frequency Domain Packet Scheduling) based on
CQI with resources assigned in a fair manner
• Uplink:
• Scheduler controls UEs and assigns appropriate grants per TTI
• Channel unaware UL scheduling based on random frequency allocation
(Channel-aware UL scheduling foreseen for RL40)
• RL30: Interference aware scheduling (IAS)
Downlink Scheduler
Algorithm
• Determine which PRBs are available (free) and
can be allocated to UEs
• Allocate PRBs needed for common channels
like SIB, paging…
• Final allocation of UEs (bearers) onto PRB.
Considering only the PRBs available after the
previous steps
– Pre-Scheduling: All UEs with data
available for transmission based on the
RL10
Soc Classification level
39 © Nokia Siemens Networks Presentation / Author / Date
available for transmission based on the
buffer fill levels
– Time Domain Scheduling: Parameter
maxNumUeDl defines how many UEs are
allocated in the TTI being scheduled
– Frequency Domain Scheduling for
Candidate Set 2 UEs: Resource allocation
in Frequency Domain including number
and location of allocated PRBs
Pre-Scheduling:
Select UEs eligible for scheduling
-> Determination of Candidate Set 1
Time domain scheduling
of UEs according to simple criteria
-> Determination of Candidate Set 2
Start
End
Frequency domain scheduling
of UEs/bearers
-> PRB/RBG allocation to UEs/bearers
Feature ID(s): LTE45
Uplink Scheduler
Algorithm
• Evaluation of the #PRBs that will be assigned to UEs
• Available number of PRBs per user: resources are assigned via PRB groups
(group of consecutive PRBs).
Time domain:
• maxNumUeUl defines the UE that can be scheduled per TTI time depending on
the bandwidth: 7UEs (5 MHz), 10UEs (10MHz), 15 UEs (15MHz) and 16 UEs
(20MHz)
Frequency Domain:
•
RL10
Soc Classification level
40 © Nokia Siemens Networks Presentation / Author / Date
• Uses a random function to assure equal distribution of PRBs over the available
frequency range (random frequency hopping)
a) b)
Feature ID(s): LTE45
Example of allocation in frequency domain:
Full Allocation: All available PRBs are
assigned to the scheduled UEs per TTI
Fractional Allocation: Not all PRBs are
assigned. Hopping function handles
unassigned PRBs as if they were allocated to
keep the equal distribution per TTI
IAS: Interference aware scheduler (UL)
• Flexi eNodeB takes into account the noise and interference measurements
together with the UE Tx power density (= UE TX power per PRB) when
allocating PRBs in the frequency domain
• Cell edge users are assigned to frequency sub-bands with low measured
inter-cell interference
• Up to 10% gain for cell edge users in low and medium loaded networks
Improvement in UL coverage by optimizing the cell edge performance
RL30
Soc Classification level
41 © Nokia Siemens Networks
• Up to 10% gain for cell edge users in low and medium loaded networks
• Easier to implement than channel aware scheduling (no sounding reference
signal used)
eNode B
measured
interference
subband with low
interference
subband with high
interference
subband with medium
interference
PRBs
Feature ID(s): LTE619
Link adaptation by AMC (UL/DL)
• Motivation of link adaptation: Modify the signal transmitted to and by a
particular user according to the signal quality variation to improve the
system capacity and coverage reliability.
• It modifies the MCS (Modulation and Coding Scheme), the transport block
size (DL) and ATB (UL)
• If SINR is good then higher MCS can be used -> more bits per byte -> more
Optimizing air interface efficiency
RL10
Soc Classification level
42 © Nokia Siemens Networks Presentation / Author / Date
• If SINR is good then higher MCS can be used -> more bits per byte -> more
throughput.
• If SINR is bad then lower MCS should be used (more robust)
• Flexi Multiradio BTS performs the link adaptation for DL on a TTI basis
• The selection of the modulation and the channel coding rate is based:
• Downlink data channel: CQI report from UE
• Uplink: BLER measurements in Flexi LTE BTS
Feature ID(s): LTE31
AMC: Adaptive Modulation and Coding
ATB: Adaptive Transmission Bandwidth
Link Adaptation / AMC for PDSCH
Procedure:
• Initial MCS is provided by O&M
(parameter INI_MCS_DL) and is
set as default MCS
• If DL AMC is not activated (O&M
parameter ENABLE_AMC_DL)
the algorithm always uses this
default MCS
• If DL AMC is activated HARQ
retransmissions are handled
START
Retrieve Default MCS
Dynamic AMC
active?
no
RL10
Soc Classification level
43 © Nokia Siemens Networks Presentation / Author / Date
retransmissions are handled
differently from initial
transmissions (For HARQ
retransmission the same MCS
has to be used as for the initial
transmission)
• A MCS based on CQI reporting
from UE , shall be determined for
the PRBs assigned to UE as
indicated by the downlink
scheduler
HARQ
retransmission?
Determine avaraged CQI
value for allocated PRBs
Use the same MCS as for
initial transmission
Determine MCS
Use Default MCS
END
yes
no
Link Adaptation / AMC for PUSCH
Functionality
• UL LA is active by default but can be deactivated by O&M parameters. If not
active, the initial MCS is used all the time
• UE scope
• Two parallel algorithms adjust the MCS to the radio channel conditions:
– Inner loop link adaptation (ILLA):
Slow Periodic Link adaptation (10-500ms) based on BLER measurements
from eNodeB
RL10
Soc Classification level
44 © Nokia Siemens Networks Presentation / Author / Date
from eNodeB
– Outer loop link adaptation (OLLA): event based
In case of long Link Adaptation updates and to avoid low and high BLER
situations, the link adaptation can act based on adjustable target BLER:
- “Emergency Downgrade” if BLER goes above a MAX BLER threshold
(poor radio conditions)
- “Fast Upgrade” if BLER goes below of a MIN BLER threshold (excellent
radio conditions)
Downlink
– fast
1 TTI
– channel aware
CQI based
– MCS selection
Uplink
– slow periodical
~30ms
– channel partly aware
average BLER based
– MCS adaptation
Comparison: DL and UL Link adaptation for PSCH
Soc Classification level
45 © Nokia Siemens Networks Presentation / Author / Date
– MCS selection
1 out of 0-28
– output
MCS
TBS
– up to 64QAM support
– MCS adaptation
+/- 1 MCS correction
– output
MCS
ATB
– up to 16 QAM support
Outer Link Quality Control (OLQC)
Feature: CQI Adaptation (DL)
• CQI information is used by the scheduler and link adaptation in such a way that a
certain BLER of the 1
st
HARQ transmission is achieved
• CQI adaptation is the basic mean to control Link Adaptation behaviour and to
remedy UE measurement errors
• Only used in DL
Optimize the DL performance
RL10
Soc Classification level
46 © Nokia Siemens Networks Presentation / Author / Date
• Only used in DL
• Used for CQI measurement error compensation
– CQI estimation error of the UE
– CQI quantization error or
– CQI reporting error
• It adds a CQI offset to the CQI reports provided by UE. The corrected CQI report
is provided to the DL Link adaptation for further processing
• CQI offset derived from ACK/NACK feedback
Feature ID(s): LTE30
Power Control
Downlink:
• There is no adaptive or dynamic power control in DL but semi-static power
setting
• eNodeB gives flat power spectral density (dBm/PRB) for the scheduled
resources:
– The power for all the PRBs is the same, it is evenly distributed over the
spectrum
Improve cell edge behaviour, reduce inter-cell interference and power consumption
RL10
Soc Classification level
47 © Nokia Siemens Networks Presentation / Author / Date
spectrum
– If there are PRBs not scheduled that power is not used and the power of the
remaining scheduled PRBs doesn’t change:
Total Tx power is max. when all PRBs are scheduled. If only half of the PRBs
are scheduled the Tx power is half of the Tx power max ( i.e. Tx power max -
3dB)
• Semi-static: PDSCH power can be adjusted via O&M parameters
– Cell Power Reduction level dlCellPwrRed [0...10] dB attenuation in 0.1 dB steps
Feature ID(s): LTE27
Power Control
Downlink Power Boosting for Control Channels
• Offsets determine power shifts for subcarriers which carry PCFICH/PHICH or
cell-specific Reference Signal
RL30
Benefits:
• Better PCFICH detection avoids throughput
degradation due to lost subframes
• Higher reliability of PHICH avoids
unnecessary retransmissions causing
capacity degradation and additional UE
power consumption
Soc Classification level
48 © Nokia Siemens Networks Presentation / Author / Date
Feature ID(s): LTE430
power consumption
• Better channel estimation avoids throughput
degradation and improves HO performance
Cons:
• Small degradation on PDSCH subcarriers:
Subcarrier power boosting only allowed if
the excess power is withdrawn from the
remaining subcarriers
More info:
https://sharenet-
ims.inside.nokiasiemensnetworks.com/Overview/D
428533788
Power Control
Uplink:
• Uplink PC is a mix of Open Loop Power Control and Closed Loop Power Control:
• Closed Loop PC component f(i): Makes use of feedback from the eNB. Feedback
are TPC (Transmit Power Control commands) send via PDCCH to instruct the UE
Improve cell edge behaviour, reduce inter-cell interference and power consumption
] )}[ ( ) ( ) ( ) ( )) ( ( log 10 , min{ ) (
_
0 10
dBm i f i PL j j P i M P i P
TF
PUSCH
PUSCH CMAX PUSCH
+ ∆ + ⋅ + + = α
RL10
Soc Classification level
49 © Nokia Siemens Networks Presentation / Author / Date
are TPC (Transmit Power Control commands) send via PDCCH to instruct the UE
to increase or decrease its transmit power
Feature ID(s): LTE27&LTE28
• UL Power control is Slow power
control: every 100ms
– No need for fast power control as
in 3G: if UE Tx power was high it
incremented the co-channel for
other UEs
– In LTE each UE has their own
channel (subcarriers)
Conventional and Fractional Power Control
• Conventional PC schemes:
– Attempt to maintain a constant SINR at the receiver
– UE increases the Tx power to fully compensate for increases in the path loss
• Fractional PC schemes:
– Allow the received SINR to decrease as the path loss increases.
– UE Tx power increases at a reduced rate as the path loss increases. Increases in path
loss are only partially compensated.
– [+]: Improve air interface efficiency and increase average cell throughputs by reducing
intercell interference
Soc Classification level
50 © Nokia Siemens Networks Presentation / Author / Date
• 3GPP specifies fractional power control for the PUSCH with the option to disable
it and revert to conventional based on α
Conventional Power
Control: α=1
If Path Loss increases by
10 dB the UE Tx power
increases by 10 dB
Fractional Power
Control: α ≠ { 0 ,1}
If Path Loss
increases by 10 dB
the UE Tx power
increases by <10 dB
UE Tx
Power
UE Tx
Power
UL
SINR
UL
SINR
Power Control
Uplink (cont.):
• Uplink PC is a mix of Open Loop Power Control and Closed Loop Power Control:
• P
CMAX
: max. UE Tx power according to UE power class. E.g. 23dBm for class 3
• M
PUSCH
: # allocated PRBs. The UE Tx Power is increased proportionally to the # of
allocated RBs. Remaining terms of the formula are per RB
• P :eNB received power per RB when assuming path loss 0 dB. Depends on α
RL10
] )}[ ( ) ( ) ( ) ( )) ( ( log 10 , min{ ) (
_
0 10
dBm i f i PL j j P i M P i P
TF
PUSCH
PUSCH CMAX PUSCH
+ ∆ + ⋅ + + = α
Soc Classification level
51 © Nokia Siemens Networks Presentation / Author / Date
• P
0_PUSCH
:eNB received power per RB when assuming path loss 0 dB. Depends on α
• α: Path loss compensation factor. Three values:
– α= 0, no compensation of path loss
– α= 1, full compensation of path loss (conventional compensation)
– α ≠ { 0 ,1 } , fractional compensation
• PL: DL Path loss calculated by the UE
• Delta_TF: It links the UE Tx power to the MCS. Increases the UE Tx power to
achieve the required SINR when transmitting a large number of bits per RE (high
MCS)
Feature ID(s): LTE27&LTE28
Power Control
P0 and α
From simulation results
• α= 1: conventional power control
– increases the cell edge data rates
(coverage) only
• α= 0.5: example of fractional power
control:
– Increases average cell throughput
because the system does not
promote ‘poor’ UEs (i.e. it doesn’t
Soc Classification level
52 © Nokia Siemens Networks
promote ‘poor’ UEs (i.e. it doesn’t
give them as much power as if α=
1)
– Interference is reduced as UEs at
cell edge are allocated smaller
power so more terminals can
operate with higher MCS
Presentation / Author / Date
• If α =1 P0_PUSCH is minimum (e.g. -96dBm) to allow sufficient UE Tx power
headroom for when the path loss increases
• If α =0 Po_PUSCH is maximum (e.g. 9dBm) i.e. UE transmits at its maximum
capability independently of the PL
Radio Admission Control (RAC)
Objective: To admit or to reject the requests for establishment of Radio Bearers (RB)
on a cell basis so eNodeB is stable and gives a minimum service level per end user
• Based on number of RRC connections and number of active users per cell
– Both can be configured via parameters
RRC connection is established when the SRBs have been admitted and
successfully configured
UE is considered as active when a Radio bearer is established
RL10
Soc Classification level
53 © Nokia Siemens Networks Presentation / Author / Date
UE is considered as active when a Radio bearer is established
– Upper bound for maximum number of supported connections depends on the
BB configuration of eNB (e.g. up to 840 active UEs for 20MHz).
However, typical values for RL10/RL20 RAC are ~100…120 irrespective of the
bandwidth as, as long as DRX is not supported (RL30) the max. number of active UEs
would consume too many resources for PUCCH (scheduling requests, CQI, etc)
• HO RAC cases have higher priority than normal access to the cell
• RL20: RAC is upgraded to support the admission control of multiple DRBs.
Feature ID(s): LTE20
Transmit diversity for two antennas
Benefit: Diversity gain, enhanced cell coverage
• Each Tx antenna transmits the same stream of data with different coding and
different subcarriers -> Receiver gets replicas of the same signal which increases
the SINR.
• Synchronization signals are transmitted only via the 1
st
antenna
• eNode B sends different cell-specific reference signals per antenna
• It can be enabled on cell basis by O&M configuration
RL10
Soc Classification level
54 © Nokia Siemens Networks Presentation / Author / Date
• Processing is completed in 2 phases:
• Layer Mapping: distributing a stream of data into two streams
• Pre-coding: generation of signals for each antenna port
S2
Spatial multiplexing (MIMO) for two antennas
Benefit: Double the peak rate compared to a 1Tx antenna
Two code words
(S1+S2) are
transmitted in
parallel to one UE
which doubles
the peak rate
• Can be open loop or closed loop depending
if the UE provides feedback
Soc Classification level
55 © Nokia Siemens Networks Presentation / Author / Date
S1
• Spatial multiplexing with two code words
• Supported physical channel: PDSCH
Layer
Mapping
L1
L2
Precoding
Map onto
Resource
Elements
×
Σ
Σ
Map onto
Resource
Elements
OFDMA
OFDMA
Modulation
Modulation
Code word 1
Code word 2
×
Scale
×
×
W
2
W
1
Precoding
• Precoding generates the signals for each antenna port
• Precoding is done multiplying the signal with a precoding matrix selected from a
predefined codebook known at the eNB and at the UE side
• Closed loop: UE estimates the radio channel and selects the best precoding matrix
(the one that offers maximum capacity) and sends this information to the eNB
• Open loop: no need for UEs feedback as it uses predefined settings for SM and
precoding
Soc Classification level
56 © Nokia Siemens Networks Presentation / Author / Date
Pre-coding codebook for two transmit antenna case
DL adaptive closed loop MIMO for two antennas
• 2 TX antennas
• Dynamic selection between:
• Transmit diversity (SFBC)
• Closed loop spatial multiplexing with
two code words
• Closed loop= feedback from UE
One code word A is
transmitted via two
antennas to one UE
which improves the
link budget
A
A
Benefit: High peak rates and good cell edge performance
RL20
Soc Classification level
57 © Nokia Siemens Networks Presentation / Author / Date
• Closed loop= feedback from UE
•Pre-coding is done according to
the codebook described in TS
36.211 (also in previous slide)
• Operator configurable threshold
• Supported physical channel: PDSCH
• This feature is an improvement over
theRL10 feature: DL adaptive open loop
MIMO for two antennas feature (LTE_70)
Two code words
(A+B) are transmitted
in parallel to one UE
which doubles the
peak rate.
A
B
Feature ID(s): LTE703
MIMO, DL channels and RRM Functionality
Available MIMO options vs. channel type
In UL, Flexi eNodeB has 2Rx Div. :
• Maximum Ratio Combining
– Benefit: increase coverage by
increasing the received signal
strength and quality
RRM MIMO Mode Control Functionality
• Refers to switch between:
– Transmit Diversity (single stream)
– MIMO Spatial Multiplexing (double stream)
– SISO (1x1 SISO, 1x2 SIMO)
• Provided by eNB only for DL direction
Soc Classification level
58 © Nokia Siemens Networks Presentation / Author / Date
Available MIMO options vs. channel type
• Options for Transmit Diversity (2Tx):
– Control Channels
– PDSCH
• Options for Dual Stream (SM):
– Only DL PDSCH
• MIMO is SW feature
Channel can be configured to use MIMO mode
Channel cannot be configured to use MIMO mode
Connection Mobility Control: Handover Types
• Intra-RAT handover
– Intra eNodeB and Inter eNodeB handover
– Above handovers can also be Inter-frequency handovers (RL20) i.e. to
support different frequency bands and deployments within one frequency band
but with different center frequencies
– Data forwarding over X2 for inter eNodeB HO
– HO via S1 interface (RL20): HO in case of no X2 interface configured
between serving eNB and target eNB
Soc Classification level
59 © Nokia Siemens Networks Presentation / Author / Date
between serving eNB and target eNB
• Inter-RAT handover
– LTE to WCDMA: RL30
– WCDMA to LTE: RL40
– LTE to CDMA2000: RL40 (CDMA2000 to LTE not assigned)
– LTE GSM and GSM LTE: not assigned
Intra LTE Handover via S1
Extended mobility option to X2 handover
• Applicable for intra and inter frequency HO
• DL Data forwarding via S1
• Handover in case of
– no X2 interface between eNodeBs, e.g.
not operative, not existing or because
RL20
Soc Classification level
60 © Nokia Siemens Networks Presentation / Author / Date
not operative, not existing or because
blacklisted usage
– eNodeBs connected to different CN
elements
Feature ID(s): LTE54
• Not visible for the UE is HO is executed via X2 or S1 interface
• MME and/or SGW can be changed during HO (i.e. if source and target
eNodeB belong to different MME/S-GW)
Inter Frequency Handover
Multi-band mobility
• Network controlled and UE assisted
• UE needs to support both bands and
inter-frequency HO
• Event triggered based on DL
measurement RSRP and RSRQ
• Inter frequency measurements
RL20
Soc Classification level
61 © Nokia Siemens Networks Presentation / Author / Date
• Inter frequency measurements
triggered by events A1/A2
• Operator configurable thresholds for
coverage based (A5),
best cell based (A3) handover
Feature ID(s): LTE55
• Service continuity for LTE deployment in different frequency bands as well
as for LTE deployments within one frequency band but with different center
frequencies
• Blacklists
Inter RAT Handover to WCDMA
• Coverage based inter-RAT PS handover
• Only for multimode devices supporting
LTE and WCDMA
• Event triggered handover based on DL
measurement RSRP (reference signal
received power)
• Operator configurable RSRP threshold
RL30
Soc Classification level
62 © Nokia Siemens Networks Presentation / Author / Date
• Operator configurable RSRP threshold
• Network evaluated HO decision
• Target cells are operator configurable
Feature ID(s): LTE56
• Blacklisting
• eNB initiates handover via EPC (S1 interface used)
• CPICH EcNo or RSCP of WCDMA cells is measured previous to the HO
eNACC to GSM
Network Assisted Cell Change to GSM
Service continuity to GSM
• Network change from LTE to GSM in
RRC Connected Mode when LTE
coverage (RSRP) is ending
• Prior to actual reselection process the
measurements of 2G network are
triggered
RL30
Soc Classification level
63 © Nokia Siemens Networks Presentation / Author / Date
triggered
• Only applicable for NACC capable
devices
• Inter RAT measurements triggered by
events A1/A2
• Operator configurable handover
threshold
• Target cells for IRAT measurements can
be configured by the operator
• Blacklisting of target cells is supported
Feature ID(s): LTE442
LTE Performance
Soc Classification level
64 © Nokia Siemens Networks Presentation / Author / Date
LTE Performance
Downlink and Uplink Spectral efficiency
• LTE Spectrum Requirement: Capacity 2-4 times bigger than with
HSPA R6 baseline
Soc Classification level
65 © Nokia Siemens Networks Presentation / Author / Date
• Downlink spectral efficiency shown to
be 3 x HSPA R6 (=UTRA baseline),
which was the target of LTE
• Uplink spectral efficiency shown to be
>2 x HSPA R6, which was the target
of LTE
Key Features for LTE Downlink Spectral Efficiency
Compared to HSPA R6
MIMO = combined use of 2 tx and 2 rx
antennas
Frequency domain packet scheduling
+20%
+40%
OFDM with frequency domain
equalization
+20..70%
Compared to single antenna
BTS tx and 2-rx terminal
Not feasible in HSPA due to
Due to orthogonality
Soc Classification level
66 © Nokia Siemens Networks Presentation / Author / Date
Inter-cell interference rejection combining
or cancellation
Frequency domain packet scheduling
+10%
+40%
Total gain up to 3.1x
Not feasible in HSPA due to
cdma modulation
Possible also in HSPA but
better performance in OFDM
solution
Spectral Efficiency Relative to 10 MHz
100 %
120 %
Downlink
Uplink
LTE Efficiency vs. Bandwidth
-40% -13% Reference
• LTE maintains high efficiency with bandwidth down to 5 MHz
• The differences between bandwidths come from frequency scheduling gain and
different overheads
Soc Classification level
67 © Nokia Siemens Networks Presentation / Author / Date
0 %
20 %
40 %
60 %
80 %
1.4 MHz 3 MHz 5 MHz 10 MHz 20 MHz
LTE Peak Data Rates
• Downlink: Peak Rate 172 Mbps with 2x2 MIMO and 20 MHz
Modulation coding 1.4 MHz 3.0 MHz 5.0 MHz 10 MHz 15 MHz 20 MHz
QPSK 1/2 Single stream 0.7 2.1 3.5 7.0 10.6 14.1
16QAM 1/2 Single stream 1.4 4.1 7.0 14.1 21.2 28.3
16QAM 3/4 Single stream 2.2 6.2 10.5 21.1 31.8 42.4
64QAM 3/4 Single stream 3.3 9.3 15.7 31.7 47.7 63.6
64QAM 4/4 Single stream 4.3 12.4 21.0 42.3 63.6 84.9
64QAM 3/4 2x2 MIMO 6.6 18.9 31.9 64.3 96.7 129.1
64QAM 1/1 2x2 MIMO 8.8 25.3 42.5 85.7 128.9 172.1
64QAM 1/1 4x4 MIMO 16.6 47.7 80.3 161.9 243.5 325.1
Soc Classification level
68 © Nokia Siemens Networks Presentation / Author / Date
64QAM 1/1 4x4 MIMO 16.6 47.7 80.3 161.9 243.5 325.1
Modulation coding 1.4 MHz 3.0 MHz 5.0 MHz 10 MHz 15 MHz
QPSK 1/2 Single stream 0.7 2.0 3.5 7.1 10.8 14.3
16QAM 1/2 Single stream 1.4 4.0 6.9 14.1 21.6 28.5
16QAM 3/4 Single stream 2.2 6.0 10.4 21.2 32.4 42.8
16QAM 1/1 Single stream 2.9 8.1 13.8 28.2 43.2 57.0
64QAM 3/4 Single stream 3.2 9.1 15.6 31.8 48.6 64.2
64QAM 1/1 Single stream 4.3 12.1 20.7 42.3 64.8 85.5
64QAM 1/1 V-MIMO (cell) 8.6 24.2 41.5 84.7 129.6 171.1
20 MHz
• Uplink: Peak Rate 57 Mbps with 20 MHz and 16QAM
Bandwidth 5 MHz 10 MHz and 20 MHz
• Maximum Peak Layer 1 Rates to one user according to 3GPP specifications and
UE capability
Downlink [Mbit/s per cell]
Modulation MIMO usage
QPSK Single stream 0.9 2.3 4.0 8.0 11.8 15.8
1.4 MHz 3.0 MHz 5.0 MHz 10 MHz 15 MHz 20 MHz
Resource blocks
6 15 25 50 75 100
LTE cell bandwidth
Efficient RF band utilization for most typical start up sites
20 MHz BW for highest capacity for commercial LTE network
RL10
Soc Classification level
69 © Nokia Siemens Networks Presentation / Author / Date
Uplink [Mbit/s per cell]
Modulation MIMO usage
QPSK Single stream 1.0 2.7 4.4 8.8 13.0 17.6
16QAM Single stream 2.8 7.0 11.4 22.9 35.2 46.9
QPSK Single stream 0.9 2.3 4.0 8.0 11.8 15.8
16QAM Single stream 1.9 5.0 8.0 16.4 24.5 32.9
64QAM Single stream 4.4 11.1 18.3 36.7 55.1 75.4
64QAM 2x2 MIMO 8.8 22.2 36.7 73.7 110.1 149.8
1.4 MHz 3.0 MHz 5.0 MHz 10 MHz 15 MHz 20 MHz
Resource blocks
6 15 25 50 75 100
LTE cell bandwidth
Feature IDs: LTE115 (5 MHz) , LTE114 (10 MHz) , LTE112 (20 MHz)
Single user Peak and Average Throughputs
Example of Trial Results (Etisalat, RL10)
• More results about this and other
trials can be found in IMS:
https://sharenet-
ims.inside.nokiasiemensnetworks.com/
Open/416686784
Downlink UDP
Soc Classification level
70 © Nokia Siemens Networks Presentation / Author / Date
Note: Poor condition was not achieved during
the test due to sudden increase in the SINR
during testing session
Uplink UDP
LTE 2.6 GHz; 20MHz bandwidth
DL TCP Peak and Average sector throughputs
Example of Trial Results (Etisalat, RL10)
Soc Classification level
71 © Nokia Siemens Networks Presentation / Author / Date
LTE 2.6 GHz; 20MHz bandwidth
UL TCP Peak and Average sector throughputs
Example of Trial Results (Etisalat, RL10)
Soc Classification level
72 © Nokia Siemens Networks Presentation / Author / Date
LTE 2.6 GHz; 20MHz bandwidth
Latencies
Example of Trial Results (3HK, October 2010)
FT_03.3-4 Latency Ping
37
33
37
42
35
40
45
Max of RTT (ms)
• User plane latencies for different ping sizes: 32 Bytes, 1000 Bytes and 1500 Bytes
• Full report: https://sharenet-ims.inside.nokiasiemensnetworks.com/Open/416686784
• LTE 2.6 GHz; 10MHz bandwidth (RL10) SINR Range (dB)
Cell centre 15 <= SINR <25
Cell middle 10<= SINR <15
Cell edge 0<=SINR <10
Soc Classification level
73 © Nokia Siemens Networks Presentation / Author / Date
26
25
26
10 10 10
28
30
22
26
27
33
24
26
31
0
5
10
15
20
25
30
35
cell centre cell middle edge cell centre cell middle edge
Non-scheduled Pre-scheduled
32B
1000B
1500B
Schedule mode Location
Ping size
Cell Range
Coverage
BS antenna height [m] 30
MS antenna height [m] 1.5
Standard Deviation [dB] 8.0
Location Probability 95 %
Slow Fading Margin [dB] 8.8
Correction factor [dB] -5
Indoor loss [dB] 15
• Low Bands and FDD are best for Coverage
Soc Classification level
74 © Nokia Siemens Networks
LTE Terminals
Soc Classification level
75 © Nokia Siemens Networks Presentation / Author / Date
LTE Terminals
Class 1 Class 2 Class 3 Class 4 Class 5
10/5 Mbps 50/25 Mbps 100/50 Mbps 150/50 Mbps 300/75 Mbps Peak rate DL/UL
LTE UE Categories
• All categories support 20 MHz
• 64QAM mandatory in downlink, but not in uplink (except Class 5)
• 2x2 MIMO mandatory in other classes except Class 1
Soc Classification level
76 © Nokia Siemens Networks Presentation / Author / Date
20 MHz RF bandwidth 20 MHz 20 MHz 20 MHz 20 MHz
64QAM Modulation DL 64QAM 64QAM 64QAM 64QAM
16QAM Modulation UL 16QAM 64QAM 16QAM 16QAM
Yes Rx diversity Yes Yes Yes Yes
1-4 Tx BTS Tx diversity
Optional MIMO DL 2x2 4x4 2x2 2x2
1-4 Tx 1-4 Tx 1-4 Tx 1-4 Tx
LTE modems (widely used in trials)
LG USB Modem (Cat 3) Link to LG-G7 configuration:
Soc Classification level
77 © Nokia Siemens Networks Presentation / Author / Date
LG USB Modem (Cat 3)
Link to LG-LD100 configuration:
https://twiki.inside.nokiasiemensnetworks.
com/bin/view/LTESyVe/LG-LD100
Link to LG-G7 configuration:
https://twiki.inside.nokiasiemensnetworks.
com/bin/view/LTESyVe/LG-G7
Samsung USB Modem
https://twiki.inside.nokiasiemensnetworks.
com/bin/view/LTESyVe/LG-G7
LTE end user device examples
Huawei E398,
2100/2600 LTE
LTE/HSPA/EDGE
E.g. Tele2, Telenor
Samsung B3730
2600 LTE
LTE/HSPA/EDGE
E.g. TeliaSonera
Samsung
TD-LTE
prototype
Sequans
TD-LTE
trial
device
LG Adrenaline
AD600
1700/2100/700 LTE
LTE/HSPA/EDGE
AT&T
L-02C USB-modem
2100 LTE
LTE/HSPA
F-06C PC Express
Cards
NTT DoCoMo
Soc Classification level
78 © Nokia Siemens Networks
Samsung Craft
1700/2100
LTE
LTE/CDMA
MetroPCS
Many more devices coming in diverse band combinations along
communication service providers requirements.
Samsung N350
LTE/HSPA+
Pantech
UML290
USB modem
700 LTE
LTE/EVDO
Verizon
NTT DoCoMo
LG VL600
USB
modem
700 LTE
LTE/EVDO
Verizon
AVM FRITZ!Box
WLAN router
800 (1800/2600)
LTE
O2 Germany
Huawei B390
Router
800 LTE
DT, O2
Germany
LTE Radio Planning
Soc Classification level
79 © Nokia Siemens Networks Presentation / Author / Date
Radio Planning Process Overview
• DIMENSIONING: Computation of number of sites to serve
certain area to fulfil customer requirements (Dim Tool)
• NOMINAL PLANNING: Creation of a nominal Plan
– Coverage planning with planning tool (i.e. Atoll, Planet)
Based on coverage thresholds
– Capacity analysis
– Site surveys and site pre-validation
DIMENSIONING
Nominal
Planning
Soc Classification level
80 © Nokia Siemens Networks Presentation / Author / Date
• DETAILED PLANNING:
– Capacity analysis with planning tool
– Site validation
– eNodeB Parameter planning (i.e. frequency, site data built
with default parameters)
• PRE-LAUNCH OPTIMISATION: Cluster acceptance
– Drive test measurements, analysis and changes
implementation
– Data build assessment/ consistency
Detailed
Planning
Pre-launch
Optimisation
LTE Dimensioning
Soc Classification level
81 © Nokia Siemens Networks Presentation / Author / Date
Purpose and Scope
• Scope of dimensioning:
• Scope of the dimensioning tool:
Calculate the number of sites required to serve certain area while fulfilling the
coverage and capacity requirements.
To define a network configuration that meets the expected traffic and service
quality based on the operator’s business case
Soc Classification level
82 © Nokia Siemens Networks Presentation / Author / Date
COVERAGE OUTPUT:
Coverage cell area
CAPACITY
REQUIREMENTS:
Serve a given traffic
density
COVERAGE REQUIREMENTS:
Achieve a ‘required SINR’/target
cell throughput at cell edge
CAPACITY OUTPUT:
Capacity cell area
Link Budget
Soc Classification level
83 © Nokia Siemens Networks Presentation / Author / Date
Coverage Dimensioning: Link Budget
• Estimating maximum allowable path loss for a single radio link
• Calculate the cell ranges for the different clutter types based on the maximum
allowable path loss and on the propagation environment
Antenna gain, feeder/cable losses, noise figures, etc.
Transmitter/receiver end modeling
User data rate, system overhead, cell load,
coverage reliability, BLER, number of
Requirements
Soc Classification level
84 © Nokia Siemens Networks Presentation / Author / Date
Path Loss
max _ DL max _ DL max _ DL max _ DL
Path Loss
max _UL max _UL max _UL max _UL
Cell Range
Clutter type, propagation model, channel model, etc.
Propagation environment
coverage reliability, BLER, number of
retransmissions, etc.
Transmitting end modeling
• EIRP: Effective Isotropic Radiated Power
MIMO body
TMA
ins feeder antenna antenna Tx
G L L L G P EIRP + − − − + =
_
Tx Power per antenna connector:
• eNodeB 8/20/40/60 W license
based control
• UE 23± 2dBm
Antenna Gain
• 18dBi (although variable
with frequency band and
antenna type)
Soc Classification level
85 © Nokia Siemens Networks Presentation / Author / Date
• UE 23± 2dBm
Feeder Loss (only in DL):
• 0.4 dB in DL with Feederless
solution
• 3 dB in DL otherwise (exemplary
value)
antenna type)
TMA (MHA) insertion loss
• Only affects downlink
• 0.5 dB if TMA is used
Body Loss (UE only)
• 0 dB for PC cards/laptops
Total power increase due to
transmit diversity techniques
• 3 dB in DL for 2Tx diversity if
not already considered in SINR
Receiving end modeling
• Receiver sensitivity
SINR NF RB kHz Hz dBm S
Rx
+ + ⋅ ⋅ ⋅ + − = ) # 12 15 log( 10 / 174
Single RB bandwidth
Receiver bandwidth
Noise power
Soc Classification level
86 © Nokia Siemens Networks Presentation / Author / Date
Thermal Noise Density: 10*log (KT)+30
Noise figure (HW specific)
DL: OFDM receiver looks at the whole bandwidth, thus all
available Resource Blocks should be considered.
UL: SC-FDMA receiver looks only at the allocated bandwidth,
thus not all but only assigned Resource Blocks are assumed
in sensitivity formula.
OFDMA / SC-FDMA
Noise power
Number of Physical Resource Blocks
• DL: all available in the channel bandwidth
• UL: only those RBs allocated for
transmission
Signal to Interference Ratio
• Source: link level simulations
Receiving end modeling
Required SINR
• Required SINR is the required
signal level at the receiver
compared to noise and interference
• SINR requirement is obtained from
link level simulations
• Specific channel models are
designed for OFDM link level
simulation
– Channel model is a way to consider
Soc Classification level
87 © Nokia Siemens Networks Presentation / Author / Date
– Channel model is a way to consider
UE mobility and environment in the
link budget calculation
• Different SINR requirements are
specified for different antenna
schemes
• Tool considers EPA 5Hz and
ETU70Hz channel models
light
UE carrier
Doppler
v
v f
f
⋅
=
Example:
EPA 5Hz Doppler frequency=5Hz for 1800MHz and 3km/h
Example SINR table used by the Dim Tool
(parameters sheet) for the case DL 2Tx-2Rx
Link Budget Example
Downlink
43
dBm
0.5 dB 18 dBi
3 dB
63.5 dB
M
A
P
L

1
6
0

d
B
Soc Classification level
88 © Nokia Siemens Networks Presentation / Author / Date
Output
power per
antenna
connector
Losses
(Cable,
jumpers,
…)
eNode B
Antenna
Gain
Path loss
UE
body
loss
IM UE
ant.
gain
Receiver
Sensitivity
dBm
0 dB
2Tx
MIMO
Gain
2.1 dB
0 dB 0 dB
- 98.6
dBm
-96.5
dB
M
A
P
L

1
6
0

d
B
EIRP
Dimensioning Tool
V2.3.4
Soc Classification level
89 © Nokia Siemens Networks Presentation / Author / Date
V2.3.4
LTE Dim Tool Overview
Input parameters Outputs
User Interface
Network
dimensioning
(site count)
• Operating band
• Transmitter/receiver
parameters
• BLER
• Propagation data
• Channel model
•Spectral Efficiency
(SL)
• Areas
• No. of Subscribers
• Phases
• Subscribers densities
• Antenna Diversity
• Channel BW
• Scheduler
• Cell Load
Soc Classification level
90 © Nokia Siemens Networks
Link Budget
Capacity
dimensioning
Traffic
dimensioning
- Calculation - Inputs/Outputs
• Maximum Path loss
• Cell ranges (outdoor and indoor)
• Cell area,
• Site-to-site distance
• UL/DL sector (cell)
throughputs.
ONLY valid for
outdoor scenarios!
•System Overhead
•Required SINR (LL)
•Interference (SL)
• For each application:
• Call duration
• Data rates
• Protocol
Overheads…
SL: System Level Simulations
LL: Link Level Simulations
Baseband
dimensioning
Link Budget Module
Soc Classification level
91 © Nokia Siemens Networks Presentation / Author / Date
Link Budget Module
Overview
• Link Budget is calculated based on
service throughput defined by the user
– Cell range also considers a given service or
cell edge criteria
• Link Level (LL) simulations,4GMax
– Define a SINR for each MCS
• System Level (SL) simulations, MoRSE
– To calculate the interference margin
Coverage
- EIRP
- RX sensitivity
- Other margins (i.e. body
loss, gains, interference
margin)
Maximum Allowable
Path Loss
- Carrier frequency
- eNB / UE height
- Clutter specific
Soc Classification level
92 © Nokia Siemens Networks Presentation / Author / Date
– To calculate the interference margin
• From v2.3.4 is possible to calculate indoor
Link Budget by the inclusion of 3 different
indoor propagation models:
– WINNER A1
– COST231 Multi-Wall
– ITU-R, P1238
• More information about indoor planning
can be found in:
– Annex D of E-UTRAN guideline: Indoor
planning
Path Loss
Propagation
Propagation models:
macro and indoor
Coverage reliability
- Clutter specific
corrections
- Shadowing std.
deviation
Cell range
Site count
Link Budget Module
General Parameters
• Operating Band:
– 3GPP TS 36.104 specifies 19 operating bands for FDD
– Dimensioning tool generalises these to 730, 750, 800, 850, 900, 1500, 1700, 1800,
1900, 2100 and 2600 MHz
– Defined by customer
• RF Unit:
– Flexi RF modules FDD, 20W, 30W and 40W Flexi RRH, 0.1W Femto (in RL40)
– Default SW license is for 20W (FDD), using any other power has additional SW license
Soc Classification level
93 © Nokia Siemens Networks Presentation / Author / Date
– Default SW license is for 20W (FDD), using any other power has additional SW license
cost
– Power is referred to the power at 1 single antenna connector
– Usually defined by Customer
• UE Power Class:
– Defined by 3GPP Class 3: 23 dBm +/- 2 dBm.
• Channel Bandwidth:
– 3GPP TS 36.104 specifies values of 1.4, 3, 5, 10, 15 and 20 MHz
– Defined by customer.
Note: RL10 supports 5, 10 and 20 MHz;
RL20/RL30 additionally support 15MHz
Link Budget Module
Transmitting End
Tx Power per Antenna [dBm]
• DL: eNodeB
– Automatically updated by the tool
when selecting the flexi RF module
in General Parameters
– Typical value: 43dBm (20W)
• UL: UE
Antenna Gain [dBi]
• DL: eNodeB
– Antenna gain changes with the antenna
type and frequency band
– Common value: 18 dBi directional antenna
Soc Classification level
94 © Nokia Siemens Networks Presentation / Author / Date
• UL: UE
– Automatically updated by the tool
when selecting the UE Power
Class in General Parameters
– Typical value: 23dBm (UE Class 3)
• UL: UE
- 0 dBi for UE antenna
- CPEs: Variable gains
- Outdoor: 14 dBi
- Indoor: 2 dBi
Link Budget Module
Transmitting End
Feeder Loss [dB]
• 0.4 dB if Feederless solution (jumper
looses)
• 2 dB feeder solution w/o TMA
• 2.4 dB if feeders with TMA used (2 dB
feeders + 0.4dB additional jumpers for
TMA). Automatically updated if TMA is
enabled
TMA (MHA) Insertion Loss [dB]
• 0.5 dB assumed if TMA in use, otherwise 0
dB. Editable from parameters worksheet
• only considered in calculations if TMA is
enabled
• No TMA used with feederless solution
Soc Classification level
95 © Nokia Siemens Networks Presentation / Author / Date
Body Loss [dB] (only UL)
• UE: 0 dB (data user) and 2-3dB (VoIP
users)
• Otherwise (card) : 0dB
User EIRP [dBm]
EIRP: Tx Power per Antenna + Antenna Gain – Feeder Loss – TMA Insertion Loss (if TMA
is present) + Total Tx Power Increase
0.4 dB 0.4 dB
DL Loss
0.4 dB
Carrier in eNB
DL Loss
1.3 dB
(1.8dB)
LTE
Feeder solution
(with <=15m 7/8” cables)
32W
43W
39W
UL Loss
1.3 dB
(1.8dB)
UL Loss
0.4 dB
e.g.142 dB
141.6dB
~1.23 km
Downlink Uplink
Downlink Uplink
Feederless Solution
0.4 dB
MHA
0.5 dB
0.4 dB
Feeder solution
(with >=20m 7/8” cables + MHA)
DL Loss
3.0 dB
21.5W
UL Loss
0 dB
Downlink Uplink
Rooftop Model site pricing comparison – Feederless and
feeder solution performance differences
LTE
LTE
e.g.142 dB e.g.142 dB
Soc Classification level
96 © Nokia Siemens Networks Presentation / Author / Date
DL RF power lost in antenna line
43W – 0.4dB = 39W (or 2 x 19.5W)
-10% when using feederless
0.4 dB
0.5-1 dB
7/8” 2.1.GHz
0.5 dB =7.5m
1 dB = 15m
DL RF power lost in antenna line
43W – 1.3dB = 32W (or 2 x 16W)
-25% when 7/8” cable 7.5m
Carrier in eNB
Carrier in eNB
(1.8dB)
43W
(1.8dB)
140.7 dB
1.16 km, 2.6 km
2
(2.45 sqkm)
~1.23 km
~2.94sqkm
UL site area degradation vs. feederless
-12% when 7/8” cable 7.5 m
-17% when 7/8” cable 15 m
0.4 dB
>1.2 dB
Carrier in eNB
0.4 dB
3.0 dB
43W
0 dB
~142 dB
DL RF power lost in antenna line
43W – 3dB = 21.5W (or 2 x 10.75W)
-44% when 7/8” cable 20m
UL site area can be slightly higher than
with feederless, but depends on
antenna line quality
Feederless provides:
Higher capacity
Higher coverage
Better overall RF performance
Less sites
Link Budget Module
Receiving End
Noise Figure [dB]
• NF depends on the receiver equipment design
and represents the additive noise generated by
various HW components
DL: UE
– Default value: 7dB (pessimistic)
UL: eNodeB
– Automatically updated by the tool.
Additional Gains [dB]
– Possibility of considering additional
gains or losses. In case of additional
losses the number entered must be
negative
– Default value: 0dB
Soc Classification level
97 © Nokia Siemens Networks
– Automatically updated by the tool.
– Default values can be changed in the
corresponding table inside the parameter
sheet (see previous slide)
– Default values:
2 dB for eNodeB (FDD HW with TMA)
2.2 dB for eNodeB (FDD HW w/o TMA)
2.8 dB for eNodeB (TD-LTE HW with
TMA)
3 dB for eNodeB (TD-LTE HW w/o TMA)
Link Budget Module
System Overhead
• Overheads are automatically calculated by the tool and indicate how many
resources are left for user data
• Total Number of PRBs per TTI:
Depends on the available BW
1.4 MHz: 6 RBs
3 MHz: 15 RBs
5 MHz: 25 RBs
10 MHz: 50 RBs
Soc Classification level
98 © Nokia Siemens Networks Presentation / Author / Date
10 MHz: 50 RBs
15 MHz: 75 RBs
20 MHz: 100 RBs
• NOTE: The eNodeB scheduler works with TTI (Transmission Time Intervals).
Therefore, within the dimensioning tool context, the term RB is referred to 1ms
(TTI) rather than 0.5ms periods as per the standard. RB within this context
should be understood as a ‘scheduling resource block’ of 1ms interval in time
domain and 12 subcarriers in frequency domain
Link Budget Module
System Overhead
• Cyclic Prefix (CP):
– Two options:
Normal: 7 symbols/slot; 7x12: 84
RE per RB
Extended: 6 symbols/ slot; 6x12:
72 RE per RB
– Default: Normal
– Extended CP Not common
dimensioning case. Currently not
• Number of PDCCH Symbols per
Subframe
– PDCCH carries Downlink Control
Information (DCI)
Soc Classification level
99 © Nokia Siemens Networks Presentation / Author / Date
dimensioning case. Currently not
supported. Use in cells with long
delay spread
• Number of OFDM symbols per
subframe:
– Depends on the type of CP selected
Normal: 7 symbols per slot x 2
slots per subframe :14 symbols
Extended: 6 symbols per slot x 2
slots per subframe: 12 symbols
Information (DCI)
– Signalled by the PCFICH under the
indication of the eNodeB RRM
– Based on number of active connections
(increase in active connections = increase in
PDCCH signalling)
– Automatically updated by the tool when
selecting the Bandwidth
– Possible values: 1 to 4 PDCCH symbols
Dimensioning recommendation: 3 PDCCH
symbols per frame
Link Budget Module
System Overhead
• Number of PRBs for PUCCH
– PUCCH carries the Uplink Control
Information (UCI) i.e. scheduling requests,
HARQ ACK/NACKS, CQI and MIMO
information (Rank Indication and
Precoding Matrix Indication)
– PUCCH PRBs are always allocated at the
edges of the channel bandwidth to avoid
fragmenting PRBs allocated to PUSCH
– Automatically updated by the tool when
Soc Classification level
100 © Nokia Siemens Networks Presentation / Author / Date
– Automatically updated by the tool when
selecting the Bandwidth
– Recommendation (used by tool)
1 PUCCH PRB in 1.4 MHz bandwidth
2 PUCCH PRBs in 3 and 5 MHz bandwidth
4 PUCCH PRBs in 10 MHz bandwidth
6 PUCCH PRBs in 15 MHz bandwidth
8 PUCCH PRBs in 20 MHz bandwidth
• RACH Density for 10ms (frame)
– RACH resources occupy 6PRB in
frequency domain (1.08MHz) and can
occupy 1, 2 or 3 subframes (ms) in time
domain
– Density indicates how many RACH
resources are used per 10ms frame and it
is part of the different preamble
configurations
– Recommended: 1 (1 RACH resource per
frame)
The scope of RACH Density and Number of
PRBs for PUCCH in the tool is to calculate UL
overheads
Link Budget Module
System Overhead Downlink
Reference Signal
- If 1 Tx antenna: 4 Reference Signals per RB
- If 2 Tx antenna, there are 8 Reference Signals per Resource Block
- If 4 Tx antenna, there are 12 Reference Signals per Resource Block
Example below: Normal CP (84 RE) and 2Tx antenna, overhead = 8 / 84= 9.52 %
Primary Synchronization Signal (PSS)
- Occupies 144 Resource Elements per frame (20 timeslots) I.e. (62 subcarriers +10 DTx) x
Soc Classification level
101 © Nokia Siemens Networks Presentation / Author / Date
- Occupies 144 Resource Elements per frame (20 timeslots) I.e. (62 subcarriers +10 DTx) x
2 times/frame
Example below: Normal CP and 2Tx antenna, overhead = 144 / (84 × 20 × 50) = 0.17 %
Secondary Synchronization Signal (SSS)
– Identical calculation to PSS
Link Budget Module
System Overhead Downlink
PDCCH, PCFICH and PHICH
- The combination of PDCCH, PCFICH and PHICH is able to occupy the first 1, 2 or 3
time domain symbols per TTI
- The number of RE occupied per 1 ms TTI is given by (12 × y – x), where:
• y depends upon the number of occupied time domain symbols per TTI (1, 2 or 3)
• x depends upon the number of RE already occupied by the Reference Signal
x = 2 for 1 transmit antenna
x = 4 for 2 transmit antenna
Soc Classification level
102 © Nokia Siemens Networks Presentation / Author / Date
x = 4 for 4 transmit antenna when y = 1
x = 8 for 4 transmit antenna when y = 2 or 3
Example in screen shot illustrates the case for normal CP, 2 Tx and the first 3 time domain
symbols occupied:
overhead = (12 × 3 - 4) / (12 × 7 × 2) = 19.05%
Link Budget Module
System Overhead Uplink
Reference Signal
• The ‘Demodulation Reference Signal is sent within the 4
th
time domain RE of each RB
occupied by the PUSCH
• Occupies all RBs not used by the PUCCH. For a 1.4 MHz Channel Bandwidth, the PUCCH
occupies 1 RB per Slot. The number of RE per RB is 84 when using the normal CP. This
means the overhead generated by the Ref. Signal is (5 × 12)/(6 × 84) = 11.9 %
• For the normal cyclic prefix:
Channel BW PUCCH RB/slot Overhead
1.4 MHz 1 ((6-1) × 12) / (6 × 84) = 11.9 %
Soc Classification level
103 © Nokia Siemens Networks Presentation / Author / Date
1.4 MHz 1 ((6-1) × 12) / (6 × 84) = 11.9 %
3 MHz 2 ((15-2) × 12) / (15 × 84) = 12.38 %
5 MHz 2 ((25-2) × 12) / (25 × 84) = 13.14 %
10 MHz 4 ((50-4) × 12) / (50 × 84) = 13.14 %
15 MHz 6 ((75-6) × 12) / (75 × 84) = 13.14 %
20 MHz 8 ((100-8) × 12) / (100 × 84) = 13.14 %
Link Budget Module
System Overhead Uplink
PRACH
• PRACH uses 6 Resource Blocks in the frequency domain.
• The location of those resource blocks is dynamic. Two parameters from RRC layer define it:
– PRACH Configuration Index: for Timing, selecting between 1 of 4 PRACH durations and
defining if PRACH preambles can be send in any radio frame or only in even numbered
ones
– PRACH Frequency offset: Defines the location in frequency domain
• PRACH overhead is calculated as: 6RBs * RACH Density / (#RB per TTI)* 10 TTIs per
frame
Soc Classification level
104 © Nokia Siemens Networks Presentation / Author / Date
frame
– RACH density: how often are RACH resources reserved per 10 ms frame i.e. for RACH
density: 1 (RACH resource reserved once per frame)
Channel BW Overhead
1.4 MHz (6 × 1) / (6 × 10) = 10 %
3 MHz (6 × 1) / (15 × 10) = 4 %
5 MHz (6 × 1) / (25 × 10) = 2.40 %
10 MHz (6 × 1) / (50 × 10) = 1.20 %
15 MHz (6 × 1) / (75 × 10) = 0.8 %
20 MHz (6 × 1) / (100 × 10) = 0.6 %
Link Budget Module
System Overhead Uplink
PUCCH
• Ratio between the number of RBs used for PUCCH and the total number of RBs
in frequency domain per TTI
Channel BW PUCCH RB/slot Overhead
1.4 MHz 1 1 / 6 = 16.67 %
3 MHz 2 2 / 15 = 13.33 %
5 MHz 2 2 / 25 = 8 %
10 MHz 4 4 / 50 = 8 %
Soc Classification level
105 © Nokia Siemens Networks Presentation / Author / Date
10 MHz 4 4 / 50 = 8 %
15 MHz 6 6 / 75 = 8 %
20 MHz 8 8 / 100 = 8%
Additional Overhead (%)
• Tool allows to consider additional overheads not included in the overhead section
• Modulation and Coding Scheme
– 3GPP TS 36.211 specifies modulation schemes of QPSK, 16QAM and 64QAM
for the Physical DL and UL Shared Channel
– Tool automatically selects the best possible MCS for DL and UL (automatic
link adaptation) maximizing the MAPL for a certain Cell Edge User Throughput
• Service Type
–
Link Budget Module
Capacity
Soc Classification level
106 © Nokia Siemens Networks Presentation / Author / Date
– Two possible options:
Data
AMR for different codecs (VoIP)
– Default: Data
– Typical dimensioning cases will be for data. However, customer may require
specific dimensioning for VoIP: v 2.3.4 offers the possibility to do the
dimensioning for VoIP as cell-edge service. Default in this case is: AMR12.2
Modulation and Coding Scheme (MCS)
3GPP TS 36.213 specifies tables to:
• link the MCS Index to a Modulation Order (modulation type) and TBS Index
• link the TBS Index to a Transport Block Size (TBS) for a specific number of Physical Resource
Blocks (PRB)
Only a subset of the complete table (3GPP TS 36.213 specifies 110 columns)
Soc Classification level
107 © Nokia Siemens Networks Presentation / Author / Date
Modulation Order
2 ≡ ≡≡ ≡ QPSK
4 ≡ ≡≡ ≡ 16QAM
6 ≡ ≡≡ ≡ 64QAM
High MCS corresponds
to high throughput
Link Budget Module
Capacity
• Cell Edge User Throughput (kbps)
– Target throughput requirement to be achieved at the cell edge; minimum
single UE throughput requirement. Determines the service that can be
provided at the cell border.
– It can limit the MCS to be used if the required cell edge user throughput is
higher than the Max MCS Throughput
– Normally customer requirement
– Tool automatically updates the MCS each time a different cell edge user
Soc Classification level
108 © Nokia Siemens Networks Presentation / Author / Date
– Tool automatically updates the MCS each time a different cell edge user
throughput value is entered.
Link Budget Module
Capacity: VoIP Dimensioning
• Default scenario for VoIP dimensioning is represented in scenario 2 of the tool
• Service Type: AMR + codec
• Cell Edge User Throughput: automatically updated based on codec according
to values in the VoIP worksheet of the tool
• VoIP Layer 2 Segmentation Order (UL) RL30:
– Divides packets into segments on L2. Each segment is transmitted in a smaller
Transport Block than the original one. MCS can be more robust and VoIP
coverage increases
Soc Classification level
109 © Nokia Siemens Networks
coverage increases
– Capacity decreases and cell edge user throughput is automatically adjusted
because the additional RLC/MAC overhead
– Not to be used together with TTI bundling (RL40)
Presentation / Author / Date
Link Budget Module
Capacity
• Residual BLER/Number of Transmissions:
– Defines the number of HARQ transmissions and a residual BLER after the last
transmission
– Recommended value (data): 10% at 1
st
transmission because of the nature
of link adaptation
– Recommended value (VoIP): 1% after the 4
th
transmission
– Tool also considers the possibility of BLER 1% and 2% at 2
nd
, 3
rd
and 4
th
transmissions but its use is only recommended in particular cases not strictly
Soc Classification level
110 © Nokia Siemens Networks Presentation / Author / Date
transmissions but its use is only recommended in particular cases not strictly
related to an RFQ dimensioning (e.g. comparison between LTE and
GSM/UMTS link budgets on lower frequency bands or to show the potential of
HARQ gain)
Link Budget Module
Capacity: Number of PRBs per User
MCS = 10-16QAM TBS_index = 9
Air Interface User Throughput =
TBS set
• Number of user data bits transmitted to single user during one TTI (1 ms)
• Transport Block occupies two resource blocks in time domain
Soc Classification level
111 © Nokia Siemens Networks Presentation / Author / Date
384 / (100% - 10%) = 427 kbps
…search for TBS in I
TBS
9 >= Air
Interface
#RB_used = 3 TBS = 456 bits
456 bits / TTI = 456 bits / 1 ms = 456
kbps >= 427 kbps
Conclusion: # RB used= 3
Link Budget Module
Capacity
Channel Usage per TTI
• Resource utilization by the user: how
many PRBs are allocated for
PDSCH/PUSCH
• Ratio between Number of RB per User
and Total number of RB available in the
frequency domain
Transport Block Size for
Modulation Efficiency
• Transmitted bits per modulated symbol
Soc Classification level
112 © Nokia Siemens Networks Presentation / Author / Date
Transport Block Size for
PDSCH/PUSCH
• Defined by cell edge throughput and
BLER requirements
• Determines the Number of RBs per
User
order
M overhead RE RB
TBS
CR
⋅ − ⋅ ⋅
=
) 1 ( # #
TBS: transport block size [bits]
Overhead: system overhead
Modulation order: QPSK=2, 16QAM=4, 64QAM=6
#RE per RB: 168 normal CP, 144 extended CP
Effective Coding Rate
• Coding rate applied on PDSCH/PUSCH
with respect to the allocated resource
blocks, TBS and overheads
• Transmitted bits per modulated symbol
Link Budget Module
Channel
Channel Model
Link level simulation results available for:
• Enhanced Pedestrian A 5Hz (EPA 05)
propagation channel: 5Hz Doppler shift (low
speed mobiles)
• Enhanced Typical Urban (ETU70)
propagation channel: 70Hz Doppler shift
valid for higher speed mobiles (>30km/h)
Soc Classification level
113 © Nokia Siemens Networks Presentation / Author / Date
Doppler Freq = Carrier Freq * UE Speed / Speed Of Light
E.g. If 2000MHz frequency band then 5Hz Doppler shift corresponds roughly to 3km/h
Antenna Configuration
• DL: 2Tx -2Rx refers to single stream 2x2 MIMO (transmit diversity only) because at cell edge
is not likely to have Spatial Multiplexing (SM)
• When calculating capacities MIMO Spatial Multiplexing is considered
• UL: 2Rx is the default option in Flexi eNB
Link Budget Module
Channel
Tx/Rx Algorithm at eNB
• Allows to select the type of transmit diversity to be considered in calculations: Open Loop (
OL TxDiv) or Closed Loop (CL TxDiv)
• Both algorithms send one code word through the 2Tx using a pre-coding matrix when
generating the info that goes through each antenna Tx.
• In CL pre-coding matrix is based on feedback provided by UE (optimal for the radio
conditions)
• OL lacks the UE feedback therefore pre-coding matrix is always the same
Note: in 3GPP terminology, CL TxDiv
is regarded as a variant of spatial
multiplexing (single layer)
Soc Classification level
114 © Nokia Siemens Networks Presentation / Author / Date
• OL lacks the UE feedback therefore pre-coding matrix is always the same
• Benefits: Improved cell edge performance (respect OL) i.e. better DL MAPL and better
capacity
• Recommendation: Select OL TxDiv (SFCB) if dimensioning is to be aligned with RL10,
otherwise (RL20 or RL30) select CL TxDiv (with PMI) as it provides better cell capacity
results
Link Budget Module
Channel
FDPS (Frequency Domain Packet Scheduler) Type
DL : Channel aware/ Channel unaware
• NSNs DL scheduler is channel aware (i.e. Proportional Fair in time and frequency domain)
• Round Robin is the reference case in the tool for the FDPS channel aware gains
UL : Channel unaware/ Interference aware (from RL30)
• Interference aware scheduler (IAS) improves the UL coverage based on IM value such as:
– IM<=1 then IAS gain=0
Soc Classification level
115 © Nokia Siemens Networks
– IM<=1 then IAS gain=0
– IM>1 then IAS gain=1, reflected in field FDPS gain field
• Channel aware in UL is currently planned for RL40
FDPS Gain
• Round Robin is the reference case in the
tool for the FDPS channel aware gain
• Depends on the required capacity per user
• FDPS Gain table specified for a 10MHz
bandwidth. A scaling factor is applied for
other bandwidths
Link Budget Module
Channel
DL Power Boosting and PDSCH Power Penalties
• RL30 feature affecting the PCFICH, PHICH and cell specific Reference signal
• It is possible to boost the power of REs carrying the above control channels respect the
REs carrying PDSCH
• Benefits: better detection of PCFICH, higher reliability of ACK/NACK and better channel
estimation from the RS ( i.e. may improve handover)
• Cons: It reduces the power of the REs carrying PDCCH/PDSCH
• Recommendation: Off , however if it needs to be ‘On’ the effects in LiBu are small i.e.
Soc Classification level
116 © Nokia Siemens Networks
• Recommendation: Off , however if it needs to be ‘On’ the effects in LiBu are small i.e.
small reduction in DL MAPL that normally is not the limiting factor
• Below penalties are applied on PDSCH if DL power boosting is ‘on’
Link Budget Module
Channel
Number of Users per TTI (Loaded cell)
• Ratio between total number of RB
available in the frequency domain and
Number of RB per User
• Maximum number of users (100% load
=100% resource utilization) which can
be scheduled in the frequency domain
in a single TTI are:
Soc Classification level
117 © Nokia Siemens Networks Presentation / Author / Date
• 10MHz:10
• 15 MHz: 15
• 20 MHz: 20
• 1.4 MHz: 1
• 3 MHz: 3
• 5 MHz: 7
HARQ Gain
• Only applicable when using retransmissions
• Gain is the SINR delta between the required SINR for BLER 10% after 1
st
transmission and the required SINR to achieve the required BLER
Link Budget Module
Channel
Required SINR @ BLER10%
• Value comes from system level
simulations (SINR tables in the
Parameters Sheet)
• Values is for 10% BLER after 1
st
Transmission
• In order to get the required SINR,
the following inputs must be
Soc Classification level
118 © Nokia Siemens Networks Presentation / Author / Date
the following inputs must be
determined:
Modulation and Coding Scheme
Number of resource blocks
Antenna scheme
Channel model
Link Budget Module
Channel
Coding Rate Offset [dB]
• It compensates for SINR differences
between the particular link budget case
and the simulated one (link level).
• Defined as:
– SINR for the effective coding rate – min
required SINR
Soc Classification level
119 © Nokia Siemens Networks Presentation / Author / Date
Required SINR at Cell Edge [dB]
• Required signal level at the receiver
compared to noise and interference in
order to achieve the desired cell edge
throughput requirement
• Final SINR at the cell edge taking into
account possible gains (e.g. FDPS
gain and HARQ gain) and the coding
rate offset
Maximum SINR at Cell Edge [dB]
• Obtained from SL simulations (MoRSE
SL simulation for 3GPP Macro Case 1
(ISD=500m) represents the 10
th
percentile of the SINR CDF
• Input in the Interference Margin
Formula
Link Budget Module
Channel
Cell Load (%)
• Cell load represents the resource utilization in terms of RBs
• It refers to neighbour cells: no information about own cell load is considered in
LiBu as intra-cell interference is not taken into account
• Affects the Interference Margin (IM)
– High neighbour cell load increases the IM that in terms reduces the MAPL
• Affects also the cell capacity as cell load is related to the resource utilization and
Soc Classification level
120 © Nokia Siemens Networks Presentation / Author / Date
• Affects also the cell capacity as cell load is related to the resource utilization and
to the inter-cell interference level
• Recommended value: 50% (subject to change in future LTE releases)
• Customer may provide this value
• UL and DL cell load can have different values
Link Budget Module
Channel
Interference Margin (IM)
• Relation between signals received with and without interference
• DL: IM is defined by analytical methods (formula below)
• UL: value is taken from simulations due to non-deterministic user’s distribution
• Tool offers additional possibility of entering user defined values for DL and UL
• The DL Interference Margin is defined as -10 LOG(1 – Load) where load is
defined by:
Soc Classification level
121 © Nokia Siemens Networks Presentation / Author / Date
• From the formula above it shall be noted that Interference Margin is a function of
required SINR, Cell Load and Maximum SINR at cell edge
10
Edge Cell at SINR Max.
10
Edge Cell at Req.SINR
10 Load Cell 10 Load
−
× × =
Link Budget Module
Channel
Receiver Sensitivity [dBm]
• Gives and indication of receiver’s ability for detection of low level signals
SINR NF RB kHz Hz dBm S
Rx
+ + ⋅ ⋅ ⋅ + − = ) # 12 15 log( 10 / 174
Single RB bandwidth
Receiver bandwidth
Noise power
Soc Classification level
122 © Nokia Siemens Networks Presentation / Author / Date
Maximum Allowable Path Loss [dB]
• Maximum allowable attenuation of the radio wave traversing the air interface
• Excludes clutter data (e.g. penetration looses, propagation data)
– Tx EIRP – Rx Sensitivity + Rx Ant. Gain + Additional Gains - Interference Margin -
Body Losses
Link Budget Module
Propagation Model: Macro Case
General Information
• Tool considers three deployment classes each one refers to a certain BTS
Antenna Height [m], Average Penetration Loss [dB], Combined Standard
Deviation [dB] and Cell Edge Probability [%]
• User can select one of these deployment class or enter the values manually
MS Antenna Height [m]
BTS Antenna Height [m]
Soc Classification level
123 © Nokia Siemens Networks Presentation / Author / Date
• Default: 1.5 m
• Default: 30 m
Link Budget Module
Propagation Model: Macro Case
Average Penetration Loss (dB)
• Depends on clutter type and frequency band
• Recommendation: If not provided by values use the default ones according to the
deployment scenario selected
• Note: Default values are calculated for the reference of 1500 ≤ f ≤ 2600MHz. If using lower
frequency bands these values are automatically corrected by a delta as per the graph
below. This will have a big impact in the site count results!
Soc Classification level
124 © Nokia Siemens Networks
Delta values:
• - 4dB for f < 700MHz
• - 2dB for 700MHz <= f < 1500MHz
• +1dB for 2600MHz < f <= 3600MHz
• +2dB for f > 3600MHz
Link Budget Module
Propagation Model: Macro Case
Combined Standard Deviation (dB)
• Combined slow fading standard deviation
Location Probability (%)
• Probability for a user to be located in the cell area or at the cell edge
Log Normal Fade Margin (dB)
2
building
2
outdoor indoor
σ + σ = σ
Soc Classification level
125 © Nokia Siemens Networks Presentation / Author / Date
• Also Shadow Fading Margin or Slow Fading Margin
• Difference between the signal level necessary to cover the cell with a
certain probability of coverage and the average signal level at the cell edge
• Calculated using the standard deviation and location probability requirement
Link Budget Module
Propagation Model: Macro Case
Gain Against Shadowing (multi cell coverage)
• Since the UE can be standing at the edge of two or more cells the slow fading
margin can be smaller because only one of the cells needs to be offering
sufficient signal strength at any point in time
• Automatically calculated by the tool. Computation based on modified Jake’s
formula
Maximum Allowable Path Loss [dB] (clutter considered)
Soc Classification level
126 © Nokia Siemens Networks Presentation / Author / Date
Maximum Allowable Path Loss [dB] (clutter considered)
• Propagation data is included in the calculation
• MAPL (clutter not considered) – Penetration Losses – Fading Margin + Gain Against Shadowing
• Base for cell range calculations
Link Budget Module
Propagation Model: Macro Case
Propagation Model
• Tool offers the possibility of two propagation models:
– Cost 231 Model (one and two slopes)
– User Defined
• Recommended input: Cost 231/two slopes for all clutter types unless the
customer provides the propagation model data
Soc Classification level
127 © Nokia Siemens Networks Presentation / Author / Date
Link Budget Module
Propagation Model: Macro Case
• Modified Cost231-Hata
clutter
MS BS
L
km
d
s
m
h
a
m
h
MHz
f
B A L + |
¹
|

\
|
+ |
¹
|

\
|
− |
¹
|

\
|
− |
¹
|

\
|
+ = log log . log 82 13
Frequency A B
150-1500 MHz 69.55 26.16
1500-2000MHz 46.3 33.9
( (( ( ) )) ) [ [[ [ ] ]] ] ( (( ( ) )) ) ( (( ( ) )) )
( (( ( ) )) ) [ [[ [ ] ]] ] ( (( ( ) )) ) ( (( ( ) )) ) ¦ ¦¦ ¦
¦ ¦¦ ¦
¦ ¦¦ ¦
¦ ¦¦ ¦
¹ ¹¹ ¹
¦ ¦¦ ¦
¦ ¦¦ ¦
¦ ¦¦ ¦
¦ ¦¦ ¦
´ ´´ ´
¦ ¦¦ ¦
+ ++ + − −− − − −− −
+ ++ + − −− − − −− −
| || |
| || |
¹ ¹¹ ¹
| || |


\ \\ \
| || |
+ ++ +
( (( (
¸ ¸¸ ¸
( (( (

¸ ¸¸ ¸

| || |
¹ ¹¹ ¹
| || |

\ \\ \
| || |
⋅ ⋅⋅ ⋅ − −− −
= == =
ROAD
RURAL
94 . 35 f log 33 . 18 f lg 78 . 4
94 . 40 f log 33 . 18 f lg 78 . 4
SU 4 . 5
28
f
lg 2
U 0
DU 3
L
2
2
2
clutter
• Clutter correction Factors
• UE Height Correction Factors
• One slope for d>= 1km and two slopes for
Soc Classification level
128 © Nokia Siemens Networks Presentation / Author / Date
¦ ¦¦ ¦
¦ ¦¦ ¦
¹ ¹¹ ¹
¦ ¦¦ ¦
¦ ¦¦ ¦
´ ´´ ´
¦ ¦¦ ¦
< << < × ×× ×
| || |
| || |
¹ ¹¹ ¹
| || |


\ \\ \
| || |
| || |
¹ ¹¹ ¹
| || |

\ \\ \
| || |
− −− − | || |
¹ ¹¹ ¹
| || |

\ \\ \
| || |
+ ++ +
≥ ≥≥ ≥ | || |
¹ ¹¹ ¹
| || |

\ \\ \
| || |
− −− −
= == =
km 1 d ,
log50
1

m
h
log 82 . 13
MHz
f
log 9 . 13 88 . 47
km 1 d ,
m
h
log 55 . 6 9 . 44
s
BS
BS
¹
´
¦
− − −
−
=
R , SU ] 8 . 0 ) f lg( 56 . 1 [ h ] 7 . 0 ) f lg( 1 . 1 [
U DU, 4.97 )] 75h 3.2[lg(11.
) h ( a
MS
2
MS
MS
• UE Height Correction Factors
• Slopes
• One slope for d>= 1km and two slopes for
d<1km
• Two slope is an extension of one slope
model for d<1km
– If cell range >1km results are the same for one
slope and two slope models (same formula
used)
– If cell range <1 km then two slope model
provides better results
• Recommended value: 2 slopes for
all clutter types
Link Budget Module
Site Count: Macro Case
Cell Range
• Calculated based on the modified Cost231-Hata formula for each clutter type:
Site Layout Options:
• Omni
• 6 sectors
• 3-sector antenna BW> 90
o
clutter
MS BS
L
km
d
s
m
h
a
m
h
MHz
f
B A L +
|
¹
|

\
|
+
|
¹
|

\
|
−
|
¹
|

\
|
−
|
¹
|

\
|
+ = log log . log 82 13
Additional information provided by
the tool:
• Cell area (km2)
• Site area (km2)
Soc Classification level
129 © Nokia Siemens Networks Presentation / Author / Date
• 3-sector antenna BW> 90
o
• 3-sector antenna BW<= 90
o
(default)
Deployment Area (sq Km)
• Rough site count estimation, considering ONLY the coverage conditions, not
the capacity constraints. For a full (coverage and capacity) dimensioning refer to
the figures in the site count sheet
• Site area (km2)
• Inter Site Distance (km)
Capacity Module
Soc Classification level
130 © Nokia Siemens Networks Presentation / Author / Date
Capacity Calculations
• DL/UL Cell throughput automatically calculated by tool
• Algorithm calculates the Average Cell throughput (capacity) for a single cell
• Capacity is based on:
• System Level simulations (spectral efficiency) for 800MHz, 2100MHz and 2600MHz to
cover for different bands
• LiBu inputs: operating band, channel bandwidth, channel model, cell load, scheduler
and inter-site distance (ISD).
Soc Classification level
131 © Nokia Siemens Networks
• Possible to select also the MIMO settings and % of PRB utilization in the victim cell
• Cell load represents the load of the neighbour cells as per Link budget cell load. Values lower
than 100% will provide better throughputs as the interference will be lower
• Load in victim cell is considered by default 100% ( i.e. 100% PRB utilization) as it provides
better throughputs. It is not recommended to change this value
• The Deployment class should be aligned with the one in the LiBu ( i.e. basic/mature or high
end)
Capacity Calculations
Methodology
• Four representative site grids (defined by the inter site distance) have been simulated in
dynamic system level environment (MoRSE) for 800, 2100 and 2600MHz bands
• UL & DL spectral efficiency figures have been gathered for all available channel bandwidth
configurations (1.4 … 20 MHz) and for three scenarios according to the penetration losses:
– Outdoor only: 0 dB penetration loss (all UEs located outside)
– Outdoor-to-Indoor Basic & Mature: penetration loss 20dB for ISD=500m,1732m; 10dB for
ISD=3000m and 5dB for ISD=9000m. (UEs located in buildings)
Soc Classification level
132 © Nokia Siemens Networks
ISD=3000m and 5dB for ISD=9000m. (UEs located in buildings)
– Outdoor-to-Indoor High End: penetration loss 20dB for ISD=500m,1732m,3000m,9000m.
(UEs located in buildings)
• When the channel bandwidth and the ISD are known from the link budget scenario, the
spectral efficiency is interpolated/extrapolated based on a look-up table obtained from the
simulator
Capacity Calculations
Inputs
Extended UL MCS Range (RL30 onwards)
• Allows for signalling of MCS21…24 as 16QAM instead of 64QAM
which improves the data rate of Category 1…4 terminals (otherwise
limited to MCS20-16QAM since they don’t support 64QAM) by using
Most capacity inputs are
imported from LiBu sheet based
on the scenario. Further tuning
of parameters is possible:
Soc Classification level
133 © Nokia Siemens Networks
limited to MCS20-16QAM since they don’t support 64QAM) by using
larger Transport Blocks an utilizing higher coding rate with 16QAM
Capacity Calculations
Inputs
Victim Cell Always Fully Loaded (100% PRB utilization)
• Recommendation: Yes (100% PRB utilization) as it provides the best
throughput values
6-sector Deployment
• In a 6 sector deployment the average cell capacity per cell is lower due to the
interference increase of having 6 sectors
• Note however that the overall site capacity is higher than the 3 sector
Soc Classification level
134 © Nokia Siemens Networks
• Note however that the overall site capacity is higher than the 3 sector
deployment
• Default: n/a depends if link budget is done for 6 sector sites or not
Capacity Calculations
Outputs
• DL and UL spectral efficiency for the particular Link Budget scenario (inter-site
distance and bandwidth) is calculated by interpolation with the simulated results.
Soc Classification level
135 © Nokia Siemens Networks Presentation / Author / Date
Downlink Results
Purple bars obtained from simulations. Yellow bars
have been interpolated based on simulation results.
Effect of cell load on capacity calculations
• Cell load impacts the resource utilization AND the inter-cell interference level
• Simulated spectral efficiency (SE) figures consider 100% load in all cells:
– Best case from the resource utilization point of view (all resources -RBs- are utilized)
– Worse case from the interference point of view
• Tool considers by default 100% cell load when calculating cell capacity
• If cell load is other than 100% (i.e. normal case if cell load is taken from Link Budget) the
final spectral efficiency/cell throughput figures in the tool reflect the improvement (by using
an scaling factor) in SE/capacity due to the reduction of interference as load will be less than
simulated 100%
Soc Classification level
136 © Nokia Siemens Networks
simulated 100%
Inter-cell interference significantly
impacts the average cell
throughput in tight grids
(interference limited scenarios)
In typical noise limited scenarios
(ISD >3km), the effect is
neglectable
Cell Capacity Calculation Example
1. Cell capacity is estimated based on link budget
scenario (ISD and channel bandwidth). MIMO
gain is applied in case of 2 TX antennas at
eNB.
2. Spectral efficiency figures have been simulated
for 100% load case. It is needed to scale them
according to the resource utilization and inter-
cell interference level.
Step1: SE = interpolate_SE(ISD, channel_bandwidth)
Example for ISD=500m, 10MHz, 2x2MIMO, 50% load
Soc Classification level
137 © Nokia Siemens Networks Presentation / Author / Date
Step1: SE = interpolate_SE(ISD, channel_bandwidth)
Step2: C = SE x channel_bandwidth
Step3: C = C x (1 + MIMO_gain(ISD))
Step4: C = C x load x scaling_factor(load)
Step1: interpolate_SE(500m, 10MHz) = 1.19bps/Hz
Step2: C = 1.19bps/Hz x 10MHz = 11.9Mbps
Step3: C = 11.9Mbps x (1+20%) = 14.28Mbps
Step4: C = 14.28Mbps x 50% x 1.37 = 9.8Mbps
Traffic Modelling
Soc Classification level
138 © Nokia Siemens Networks Presentation / Author / Date
Traffic Model
Tool offers three ways to introduce traffic data based on customer inputs:
1. Import traffic from the ‘Traffic Model’ Sheet
– Customer provides their own traffic model and traffic figures are entered in
the Traffic Model (TM) Sheet
2. Directly enter traffic with the User Defined Option
Scope: To calculate the total amount of offered traffic data in the BH (Total
Offered Traffic)
Soc Classification level
139 © Nokia Siemens Networks Presentation / Author / Date
2. Directly enter traffic with the User Defined Option
– User calculates traffic figures outside the tool and enters the total average
traffic figures per user in the Site Count Sheet
– Can be used if the customer provides total data figures
3. Use NSN Traffic Model (TM)
– Customer doesn’t provide any traffic data. Possible to use NSN Default
values in Site Count Sheet
NSN traffic model:
https://sharenet-ims.inside.nokiasiemensnetworks.com/Overview/413311463
Traffic Model
From Traffic Model Sheet
• Represent the total traffic (sum of traffic
from all services) for DL and UL per user in
the BH
• Used as an input in the Site Count Sheet
when option ‘Import from TM Sheet’ option
is selected
• Tool reflects the most common inputs that define each service
• By default all applications except flat rate are off. It is up to the user what applications to
select
Soc Classification level
140 © Nokia Siemens Networks
select
Flat Rate
• Frequently used when no particular service is specified but just a generic application
• Typical for operator policies offering a peak rate in the subscriber contract but assuming that
not all subscribers will use the available resources simultaneously
• Link: Defined for UL and DL separately
• Subscription Rate: Peak data rate expected by an active user during the BH
• Overbooking Factor (OF): Throughput reduction. Fraction of total throughput. OF can also
be interpreted as proportion of users active and that need to be scheduled (see note for this
slide)
Traffic Model
From Traffic Model Sheet
VoIP
• Link: Both (default) when VoIP is part of the TM
because VoIP is a two-way application
• Call attempts: call attempts during BH
• Call Duration [s]: sum of the durations of all calls
during BH
• Data Rate [kbps]: data rate depends on the
codec
• Service Activity: Activity factor. Normally less than
50% since only one person talks at a time
Soc Classification level
141 © Nokia Siemens Networks
50% since only one person talks at a time
Services listed as VoIP, Streaming, Www, etc. are
examples of traffic model formats: a set of input
parameters for data volume computation
Since the customers provide this information in very
different manner, one should choose the most
appropriate format to calculate data volume
1024kbps/128kbps flat rate subscription with
overbooking of 25 (all subscribers use1/25
th
of the subscription rate or 1/25
th
of
subscribers are using the purchased
subscription flat rate)
Site Count Sheet
Soc Classification level
142 © Nokia Siemens Networks Presentation / Author / Date
Site Count Sheet
Overview
Calculates the total number of sites required
to serve certain area while fulfilling the
coverage and capacity requirements
Inputs:
• Population and geographical data
• Subscriber distribution
• Site area (from link budget)
• Site capacity based on the Link Budget
parameters and simulations
Soc Classification level
143 © Nokia Siemens Networks Presentation / Author / Date
parameters and simulations
• Average data volume per subscriber for DL
and UL
Outputs:
• Site count for Capacity (UL and DL) and
Coverage is calculated for each clutter type
and for each phase
• Others:
– Amount of required FSMx
– Throughput per eNode B
Site Count Sheet
Phase:
• Population and penetration rate are
normally customer inputs. Data is usually
provided yearly or quarterly.
• Both inputs allow for the calculation of LTE
subscribers.
NOTE: If LTE subscribers are provided
directly then, enter the subscribers in the
population field and use 100% for
penetration rate
Soc Classification level
144 © Nokia Siemens Networks Presentation / Author / Date
Area Size:
• Customer provided input per clutter type
Geographical Subscriber Distribution:
• % of subscribers for each clutter type
• Customer provided input per clutter type
• Together with the Area size allows for the
calculation of the number of subscribers per
clutter type (dense urban, urban,…)
Number of Subscribers:
• Subscriber distribution per clutter type
• Calculated as:
Total number of LTE subscribers *
Geographical Subscriber Distribution
Site Count Sheet
• Site Capacity is calculated based on
the number of cells per site and the cell
throughputs
• Cell throughputs are the figures
calculated in the Cell Capacity Sheet
• Number of capacity sites:
Capacity) Site Traffic / Offered tal Roundup(To Sites=
Soc Classification level
145 © Nokia Siemens Networks
• Number of coverage sites:
e
A
r
e
a
)
e
a
S
i
z
e
/
S
i
t
R
o
u
n
d
u
p
( A
r
S
i
t
e
s
=
Capacity) Site Traffic / Offered tal Roundup(To Sites=
Site Count Sheet
Sites (Final Figure)
• Total number of sites is defined by the maximum between the amount of sites needed for
coverage -in blue - and for capacity (UL and DL) -in orange -:
– Also calculated for all defined clutter types and phases
Soc Classification level
146 © Nokia Siemens Networks Presentation / Author / Date
Site Count Sheet
Baseband dimensioning
• This module allows to estimate HOW MANY sites are required taking into account the HW
(System Module) Limitations
• Current version contains updated figures for RL10, RL15TD,RL20 and RL30.
System Module:
Options:
– FSME: high capacity system module
– FSMD: lower capacity system module
Soc Classification level
147 © Nokia Siemens Networks
–
– FSMF+FBBB: only for TDD RL25TD
• FSME is the only one supported by
RL10/RL15TD. From RL30 is
possible to use FSMD
Product Release:
• As the number of supported active users per FSME module (see next slide) changes with the
releases it is necessary to specify the RL xx release .
• Recommended: n/a (it needs to be in line with the dimensioning/features used)
Active Subscribers
• Flexi SM processing power has a strict limitation for the number of active UEs which can be
handled
• UE in E-UTRAN RRC_Connected and with DRB (Data Radio Bearer) established but with
or without data to be transmitted in the buffer
– Term refers to terminals actively using applications as well as those which do not need to
be considered for scheduling
Site Count Sheet
Baseband dimensioning
Share of active Subscribers
• Percentage of active subscribers which should be
Soc Classification level
148 © Nokia Siemens Networks Presentation / Author / Date
• Percentage of active subscribers which should be
handled by the eNB
• Share of Active Subscriber values have been
calculated for each of NSN Traffic Models defined in
the tool:
– Voice Dominant: 11%
– Data Dominant: 40%
– Voice & Data Mix: 30%
• If a default traffic model is not used user should
assume 30% Share of Active Subscribers for
dimensioning
Site Count Sheet
Baseband dimensioning
#Sites (Baseband)
• Number of Sites required based on the number of active users:
Subscribers x ShareOfActiveSubscribers
#Sites =
#MaxActiveSubscribers x NoOfCellsPerSite
# Sites Final Site Count:
• Maximum figure (limiting) between #
DL/UL Throughputs per eNB (Mbps/site)
• Based on the total offered traffic and the final
Soc Classification level
149 © Nokia Siemens Networks Presentation / Author / Date
• Maximum figure (limiting) between #
sites needed for DL/UL capacity,
coverage and baseband
• Based on the total offered traffic and the final
# of sites
Dimensioning exercise
Soc Classification level
150 © Nokia Siemens Networks Presentation / Author / Date
Dimensioning Exercise
• Groups of 3-5 persons
• Calculate the number eNodeB necessary to fulfill the coverage, capacity and HW
requirements presented in the next slides
• Consider RL20 features enhancements when appropiate
•
Soc Classification level
151 © Nokia Siemens Networks Presentation / Author / Date
• Prepare to explain shortly the dimensioning methods used, results and the main
difficulties you experienced
• Please notice that not all parameters are defined by the operators in these cases.
You should assume reasonable values for these parameters
• Exercise based on real RFQ cases although modified to adapt to the training
Dimensioning Exercise
Link Budget Data
• Dimensioning should be
done for RL20 i.e.
considering RL20
features
• Consider all UEs as
unrestricted terminals of
maximum data rate, at
least assume class 3
terminals
• Load level is defined as
Parameter: Value:
Used DL spectrum 2670-2690 MHz
Used UL spectrum 2550 -2570 MHz
Channel BW 20 MHz
Ant. Configuration 2x2 MIMO in DL (RL20)
1x2 in UL
3 sectors per site
Transmitted power per antenna 20 W
Power UL Class 3
Soc Classification level
152 © Nokia Siemens Networks Presentation / Author / Date
• Load level is defined as
percentage of used
resource blocks (RB) in
neighbor cells
transmitting at max.
power
• Assume Feederless
solution (NSN preferred)
and no TMA
Power UL Class 3
Jumper Loss 0.5 dB
LTE Antenna Antenna Gain: 18dBi
Antenna Beam width: 65
UE Noise Figure 8 dB
Default COST231-Hata Default COST231-Hata
Area Coverage Probability 95% DU, U, SU clutter types
User Throughput @ cell edge DL 2Mpbs, UL 512kbps
Cell Load
50%
Dimensioning Exercise
LTE Subscribers in Region A Phase 1 Phase 2 Phase 3
Area per clutter type Target Area
(Km2)
Dense Urban Urban Suburban
Region A (Phase 1 to 3) 780 5% 29% 66%
Density of Population Dense Urban (pop/km2) Urban (pop/km2) Suburban (pop/km2)
Region A (Phase 1 to 3) 40,000 12,447 300
• Geographical/Population Data for Scenario
• LTE Subscribers per subscriber type
Soc Classification level
153 © Nokia Siemens Networks Presentation / Author / Date
Fixed + Nomadic Wireless 60,000 130,000 200,000
• Traffic Data
Phase
Phase 1 Phase 2 Phase 3
Total (DL/UL) Busy Hour Traffic (Gbps) 13.8 49.5 100.6
Customer provides total figures w/o detailed specification of any particular application. Consider 80/20
(%) DL/UL distribution of traffic
LTE 6 sectors vs. 3 sectors
Soc Classification level
154 © Nokia Siemens Networks Presentation / Author / Date
LTE 6 sectors vs. 3 sectors
LTE 3-sector vs 6-sector
• Enhanced Pedestrian A 5Hz (EPA05)
• Equipment parameters:
– Tx Power: eNB 40W / UE 24 dBm
– Antenna Gain: eNB 18 dBi / UE 0 dBi
– Feeder Loss: DL 0.5 dB / UL 0.5 dB (feederless)
– Noise Figure: eNB 2.0 dB / UE 7 dB
• Other features:
– eNB: 1 Tx antennas, 2 Rx antennas (MRC)
– UE: 1 Tx antenna, 2 Rx antennas (MRC)
– DL F-domain Scheduler: channel-aware
– UL F-domain Scheduler: channel-unaware
• Additional margins:
– Interference margin for 50% load (~1…2dB)
– 0 dB fast fading margin (due to scheduling gain)
LTE 3-sector (1Mbps/64kbps) LTE 6-sector (1Mbps/64kbps)
• Enhanced Pedestrian A 5Hz (EPA05)
• Equipment parameters:
– Tx Power: eNB 40W / UE 24 dBm
– Antenna Gain: eNB 19.5 dBi / UE 0 dBi
– Feeder Loss: DL 0.5 dB / UL 0.5 dB (feederless)
– Noise Figure: eNB 2.0 dB / UE 7 dB
• Other features:
– eNB: 1 Tx antennas, 2 Rx antennas (MRC)
– UE: 1 Tx antenna, 2 Rx antennas (MRC)
– DL F-domain Scheduler: channel-aware
– UL F-domain Scheduler: channel-unaware
• Additional margins:
– Interference margin for 50% load (~2..3dB)
– 0 dB fast fading margin (due to scheduling gain)
Soc Classification level
155 © Nokia Siemens Networks Presentation / Author / Date
– 0 dB fast fading margin (due to scheduling gain)
– 0 dB soft HO gain (no SHO in LTE)
– 2.5 dB gain against shadowing
– 0 dB fast fading margin (due to scheduling gain)
– 0 dB soft HO gain (no SHO in LTE)
– 2.5 dB gain against shadowing
DL 165 dB* UL 160 dB*
* Max allowable path loss (clutter not considered, only system gains/losses)
Propagation
• Operating Band
– LTE: 2600 MHz
• COST 231 Hata 2-slope propagation model with
– Antenna height NB: 30m
– Antenna height MS: 1.5m
• Clutter dependent figures (Dense Urban / Urban / Suburban / Rural)
– Std. dev.: 9 / 8 / 8 / 7 [dB]
– Cell area prob.: 93 / 93 / 93 / 90 [%]
DL 166 dB* UL 161 dB*
LTE 3-sector vs 6-sector
Urban indoor (BPL 17dB BPL)
3-sector 6-sector
Cell Range (R
3
) = 0.73 km
Cell Area = 0.35 km2
Site Area (S
3
) = 1.04 km2
Inter Site Distance (ISD ) = 1.1km
Cell Range (R
6
) = 0.77 km
Cell Area = 0.26 km2
Site Area (S
6
) = 1.54 km2
Inter Site Distance (ISD ) = 1.3km
Soc Classification level
156 © Nokia Siemens Networks Presentation / Author / Date
LTE 6-sector site solution reduces the number of coverage sites by ~35%
• LTE 6-sector site solution gives a benefit of larger coverage (mainly due to higher gain
antennas) and different network layout
• It can happen that average interference level is higher from the point of a single cell
nevertheless 6-sector solution requires 35% less sites compared to corresponding 3-sector
configuration
Inter Site Distance (ISD
3
) = 1.1km Inter Site Distance (ISD
6
) = 1.3km
LTE 3-sector vs 6-sector
Mean CELL throughput Mean SITE throughput Instantaneous USER throughput
Soc Classification level
157 © Nokia Siemens Networks Presentation / Author / Date
LTE 6-sector site solution brings >70% site throughput gain compared to 3-sector
• Single cell capacity decreases 6% mainly because of increased inter-cell interference (more
neighbours higher interference)
• In total per site, capacity is increased more than 70% in DL compared to 3-sector site
• User experience is also improved (for cell-center as well as cell-edge UEs)
LTE Rural at 800MHz (Digital Dividend)
Soc Classification level
158 © Nokia Siemens Networks Presentation / Author / Date
LTE Rural at 800MHz (Digital Dividend)
LTE Rural at 800MHz (Digital Dividend)
• Enhanced Pedestrian A 5Hz (EPA05)
• Equipment parameters:
– Tx Power: eNB 2x60W / UE 24 dBm
– Antenna Gain: eNB 18 dBi / UE 0 dBi
– Feeder Loss: DL 0.5 dB / UL 0.5 dB (feederless)
– Noise Figure: eNB 2.0 dB / UE 7 dB
• Other features:
– eNB: 2 Tx antennas, 2 Rx antennas (MRC)
– UE: 1 Tx antenna, 2 Rx antennas (MRC)
– DL F-domain Scheduler: channel-aware
– UL F-domain Scheduler: channel-unaware
• Additional margins:
– Interference margin for 50% load (~1…2dB)
– 1.6 dB gain against shadowing (only for moving mobiles)
LTE@20MHz Study case
• Different UE types to reflect various deployment
scenarios (see next slide with results)
Soc Classification level
159 © Nokia Siemens Networks Presentation / Author / Date
– 1.6 dB gain against shadowing (only for moving mobiles)
Propagation
• Operating Band
– LTE: 800 MHz
• COST 231 Hata 2-slope propagation model with
– Antenna height NB: 50m
– Antenna height MS: see next slide
• Clutter dependent figures (Dense Urban / Urban / Suburban / Rural)
– Std. dev.: 9 / 8 / 8 / 7 [dB]
– Cell area prob.: 93 / 93 / 93 / 90 [%]
LTE Rural at 800MHz (Digital Dividend)
USB modem (10dB pen. loss)
Height = 1.5m;
Antenna gain = 0dBi;
Indoor CPE (10dB pen. loss)
Height = 3m (e.g. 1
st
floor);
Handset (outdoor coverage)
Height = 1.5m;
Antenna gain = 0dBi;
Downlink
AMR12.2,
G.711
1)
Uplink
30Mbps
peak
2)
512kbps
30Mbps 512kbps
MAPL
4)
157dB
151dB
54km
36km
Cell range
150dB 17km
152dB 50km
Soc Classification level
160 © Nokia Siemens Networks Presentation / Author / Date
Height = 3m (e.g. 1
st
floor);
Antenna gain = 2dBi;
30Mbps
peak
2)
512kbps
1)
Dimensioning aligned with RL20 feature set (QCI=1 support, no TTI Bundling).
2)
Downlink does not limit the coverage (higher eNodeB transmit power in noise-limited deployment leads to better capacity); 2x60Wper sector is assumed.
3)
3dB penetration loss for window sill installation near non-coated regular window.
4)
Max allowable path loss (clutter not considered, only system gains/losses)
Outdoor CPE
Height = 5m (e.g. 1
st
floor);
Antenna gain = 14dBi;
50Mbps
peak
2)
2Mbps
Indoor CPE (3dB
3)
pen. loss)
Height = 3m (e.g. 1
st
floor);
Antenna gain = 2dBi;
18Mbps
peak
2)
128kbps
159dB 110km
152dB
157dB
50km
71km
LTE Rural at 800MHz (Digital Dividend)
AMR12.2
50Mbps/
2Mbps
2x60W
Format3 Format1 Format2 Format0
20Mbps/128kbps
30Mbps/512kbps
30Mbps/512kbps
~110km
Soc Classification level
161 © Nokia Siemens Networks Presentation / Author / Date
LTE deployment at Digital Dividend band provides extreme coverage and makes
difference for PRACH planning
• Format 0 is not applicable for coverage driven rural deployment because of too short Guard Time for timing
adjustment.
• Format 2 is not reasonable for rural deployment. It repeats the preamble sequence which is however not
needed in open rural areas.
• Format 1 is the most reasoned choice for the majority of rural deployments at low band.
• Format 3 might be needed in case of gold high-end services to subscribers with outdoor CPE.
How to improve the Link Budget
Soc Classification level
162 © Nokia Siemens Networks Presentation / Author / Date
How to improve the Link Budget?
Potential changes for discussion
Release independent (1/2):
• Lower the interference margin
– LTE air interface is not impacted by own-cell interference (as in WCDMA).
Perfect intra-cell orthogonality can be assumed for LTE. Thus one can claim the
interference margin is lower compared to 3G (WCDMA/HSPA). Simple 3G
formula : -10xlog10(1-50%)=3dB where 50% stands for the cell load
– Use values <3 dB. In particular, for the rural case (LTE800MHz) as the cells
Soc Classification level
163 © Nokia Siemens Networks Presentation / Author / Date
– Use values <3 dB. In particular, for the rural case (LTE800MHz) as the cells
will be coverage instead interference limited it can be safe to consider 1dB
• Increase UE Tx Power
– Use 24dBm (typical TX power assumed for 3G data dimensioning) instead the
default 23dBm (nominal output power for Class 3 terminals; see 3GPP TS
36.101)
How to improve the Link Budget?
Potential changes for discussion
Release independent (2/2):
• Change the deployment class from mature to ‘basic’
– Basic scenario is characterised by 2 dB less than ‘mature scenario’ in
indoor penetration looses. In some scenarios the penetration loss can be even
lower (e.g. at the window sill -3dB loss from non coated window to ‘typical’ 20
dB concrete wall loss)
– Requirement for cell area probability is lower (compared to Mature) however
Soc Classification level
164 © Nokia Siemens Networks Presentation / Author / Date
– Requirement for cell area probability is lower (compared to Mature) however
cell area probability lower than 90% for DU/U/SU might be too aggressive. On
the other hand, even 85% cell area probability for open/rural areas is
acceptable
• Change UE antenna gain (depending on the device considered)
– Default: 0dBi (no external antenna; e.g. handset, USB modem)
– Aggressive: 14dBi (CPE with outdoor high gain antenna, e.g. 800EU), 2..6dBi
(external antenna for indoor CPE/router/PCMCI card)
How to improve the Link Budget?
Potential changes for discussion
Release dependent:
They can be pointed out as future areas of improvement taken into account when the
release will be commercial
• Consider UL channel aware (RL40)
– It brings gains of 2.5dB
– Backed up by simulations
–
Soc Classification level
165 © Nokia Siemens Networks Presentation / Author / Date
– Dim Tool: Use “Additional Gains (dB)” field to enter the gains
• Change the antenna scheme:
– UL 1Tx-4Rx (RL50) instead 1Tx -2Rx
– It should be easy to deploy 4Rx (MRC) at eNB with dual cross-polar antennas.
4Rx MRC brings about 3..4.5 dB over 2Rx MRC
– Dim Tool: Change the antenna scheme for uplink
Coverage Criteria for Field Measurements
Soc Classification level
166 © Nokia Siemens Networks Presentation / Author / Date
Field measurement parameters
• Terminals are measuring from serving cell:
– RSRP (Reference Signal Received Power)
– RSRQ (Reference Signal Received Quality)
• Scanners are measuring from all decoded cells:
– RSRP
– RSRQ
– Wideband channel power, RSSI
Soc Classification level
167 © Nokia Siemens Networks Presentation / Author / Date
– Wideband channel power, RSSI
– P-SCH, S-SCH power
– Reference signal SINR
• System and link level simulations gives SINR thresholds for a certain
service level (MCS or throughput)
• RSPR and RSRQ are more common measurements
⇒Mapping from SINR thresholds to RSRP/RSRQ threshold needed
RSRP and RSRQ
RSRP:
• RSRP is the power of a single resource
element.
• UE measures the power of multiple
resource elements used to transfer the
reference signal but then takes an
average of them rather than summing
them.
• Reporting range -44…-140 dBm
3GPP RSRP Definition:
Reference signal received power (RSRP), is
defined as the linear average over the power
contributions (in [W]) of the resource elements that
carry cell-specific reference signals within the
considered measurement frequency bandwidth.
3GPP RSRQ Definition:
Reference Signal Received Quality (RSRQ) is
defined as the ratio N×RSRP/(E-UTRA carrier
RSSI), where N is the number of RBs of the E-
UTRA carrier RSSI measurement bandwidth. The
measurements in the numerator and denominator
shall be made over the same set of resource
Soc Classification level
168 © Nokia Siemens Networks Presentation / Author / Date
RSRQ:
• RSRQ = RSRP / (RSSI/N)
– N is the number of resource blocks
over which the RSSI is measured
– RSSI is wide band power, including
intracell power, interference and
noise.
• Reporting range -3…-19.5dB
shall be made over the same set of resource
blocks.
E-UTRA Carrier Received Signal Strength
Indicator (RSSI), comprises the linear average of
the total received power (in [W]) observed only in
OFDM symbols containing reference symbols for
antenna port 0, in the measurement bandwidth,
over N number of resource blocks by the UE from
all sources, including co-channel serving and non-
serving cells, adjacent channel interference,
thermal noise etc.
Mapping between RSRP, RSRQ and SINR (1/2)
• An study was conducted to establish the relationship between RSRP, RSRQ
(used by measurement terminals) and the SINR (used by SL simulations and the
dimensioning tool)
• Full study can be found: https://sharenet-
ims.inside.nokiasiemensnetworks.com/Overview/D411620577
• SNR vs RSRP has a linear relation:
RSRP vs. SNR
40.00
power noise KHz P
P
RSRP
SNR
RE n
_ _ 15
_
=
=
Soc Classification level
169 © Nokia Siemens Networks Presentation / Author / Date
-15.00
-10.00
-5.00
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
-135 -130 -125 -120 -115 -110 -105 -100 -95 -90 -85 -80 -75 -70
RSRP (dBm)
S
N
R

(
d
B
)
SNR
power noise KHz P
RE n
_ _ 15
_
=
• RSRP is measured for a single
subcarrier
– noisepower_for_15KHz= -
125.2dBm
Including Noise figure UE = 7 dB
• Assumption: RSRP doesn’t
contain noise power
Curve gives upper limit to SINR with certain
RSRP. SINR is always lower than SNR in in
live network due to interference.
Mapping between RSRP, RSRQ and SINR (2/2)
• RSRQ depends on own cell traffic load, but SINR doesn’t depend on own cell
load
– Used Resource Elements per Resource Block (RE/RB) in serving cell is an input
parameter for RSRQ -> SINR mapping
– Assumption: RSRP doesn’t contain noise power
• Equation used:
SINR =
12
RSRQ vs SINR
Soc Classification level
170 © Nokia Siemens Networks Presentation / Author / Date
– x=RE/RB
• 2RE/RB equals to empty cell. Only
Reference Signal power is
considered from serving cell.
• 12RE/RB equals to fully loaded
serving cell. All resource elements
are carrying data.
x
RSRQ
SINR
−
=
1
12
-10.00
-5.00
0.00
5.00
10.00
15.00
20.00
25.00
30.00
-20 -19 -18 -17 -16 -15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3
RSRQ (dB)
S
I
N
R

(
d
B
)
2 RE/RB
4 RE/RB
6 RE/RB
8 RE/RB
10 RE/RB
12 RE/RB
Coverage criteria for field measurements
• Coverage criteria for field measurements can be estimated with link budget tool
Depends on UL and DL parameters
• Typical coverage requirement is that 95% of the measurement samples is fulfilling
the criteria (depends on operators coverage requirements)
• Example, outdoor coverage:
Throughput requirement 4096/384kbps
20W BTS Tx power
10MHz BW
Soc Classification level
171 © Nokia Siemens Networks Presentation / Author / Date
10MHz BW
If DL only considered:
– SINR requirement ≈ 0.60dB
RSRQ>-11dB, empty serving cell
RSRQ>-13.5dB, fully loaded serving cell
RSRP>-124dBm (1dB interference assumed)
Important Note: Field measurements have shown that RSRQ can not be estimated from the
LiBu following previous formulas as LiBu tool is not a dynamic simulator. With lab
measurements it is possible to set certain load but this will not be the case in the field. RSRP
thresholds should be reliable
LiBu, RSSI and RSRP
• LiBu provides the RSSI
– RSSI = wideband power= noise + serving cell power + interference power
– RSSI at the cell edge is the Rx Sensitivity
• RSSI=12*N*RSRP
– RSRP is the received power of 1 RE (3GPP definition) average of power levels received
across all Reference Signal symbols within the considered measurement frequency
bandwidth
– RSSI per resource block is measured over 12 resource elements (in LiBU 100% of the
Soc Classification level
172 © Nokia Siemens Networks Presentation / Author / Date
– RSSI per resource block is measured over 12 resource elements (in LiBU 100% of the
power is considered i.e. 43dBm)
– N: number of RBs across the RSSI is measured and depends on the BW
• Based on the above UNDER FULL LOAD AND HIGH SNR:
RSRP (dBm)= RSSI (dBm) -10*log (12*N)
RSRP coverage thresholds
Example
Parameters:
• Cell maximum TX power per antenna 43dBm
• 2Tx MIMO used
• 10MHz carrier bandwidth
• 18dBi BTS antenna gain
• 0.4dB jumper cable loss
• Required cell edge throughput 4Mbps in DL
and 384kbps in UL
Soc Classification level
173 © Nokia Siemens Networks Presentation / Author / Date
Coverage threshold (RSRP) without LNF margin, Gain Against Shadowing
and BPL:
• = 43dBm + 18dB - 0.4dB -156.65dB - 27.78dB + (156.65-149.70)
= -116.88 dBm
Coverage threshold with LNF margin and Gain Against Shadowing:
• = 43dBm+18dB-0.4dB-156.65 dB -27.78dB + (156.65-149.70)
• +6.4dB = -110.48dBm
Coverage threshold with LNF margin, Gain Against Shadowing and BPL:
• = 43dBm+18dB-0.4dB-156.65 dB -27.78dB + (156.65-149.70) +6.4dB +22dB =-88.50dBm
RSRP Estimation Based on BCCH Measurements
• A GSM operator may want to estimate what is the difference in coverage that
would have at the same location if it was to re-use the existing GSM network as
LTE (i.e. sites, antennas)
• RSSI in GSM is a good measure as BCCH is on all the time with constant power.
Load independent measurement
• RSRPlte, independent of the load, is the power of one RE that is why it needs to
be scaled down. E.g. BW=10MHz, 50PRBs; 12*50=600 subcarriers (RE);
12*log(600)
RSRP = Pmax - 10*log(12*N) – PL
Soc Classification level
174 © Nokia Siemens Networks
RSRP
LTE
= Pmax
LTE
- 10*log(12*N) – PL
LTE
RSSI
GSM
= BCCH_DLpower –PL
GSM
RSRP
LTE
(dBm)= RSSI
GSM
(dBm) – (BCCH DL power – PmaxLTE) -10*log (12*N)
– (PL
LTE
-PL
GSM
)
Presentation / Author / Date
PL: Propagation loss
N: number of RBs
• Term (PL
LTE
-PL
GSM
) accounts for the differences in propagation if different
frequencies are used. See next slide
RSRP Estimation based on CPICH RSCP
Measurements
• A WCDMA operator may want to estimate what is the difference in coverage that
would have at the same location if it was to re-use the existing WCDMA network
as LTE (i.e. sites, antennas)
RSRP
LTE
= Pmax
LTE
- 10*log(12*N) – PL
LTE
RSRP
CPICH
= Pmax
UMTS
-10*log(Pmax
UMTS
/P
CPICH
) –PL
UMTS
From both equations:
RSRP (dBm) = RSRP - (Pmax - Pmax ) - (10*log(12*N) -
PL: Propagation loss
N: number of RBs depending on bandwidth
Soc Classification level
175 © Nokia Siemens Networks
RSRP
LTE
(dBm) = RSRP
CPICH
- (Pmax
LTE
- Pmax
UMTS
) - (10*log(12*N) -
10*log(Pmax
UMTS
/P
CPICH
)) -(PL
LTE
- PL
UMTS
)
• The path loss difference (delta: PL
UMTS
- PL
LTE
) is meant for propagation
differences in different frequency bands. It can be estimated in different ways. E.g.
from Okumura Hata or from measurements
Presentation / Author / Date
clutter
MS BS
L
km
d
s
m
h
a
m
h
MHz
f
B A L + |
¹
|

\
|
+ |
¹
|

\
|
− |
¹
|

\
|
− |
¹
|

\
|
+ = log log . log 82 13
Frequency A B
150-1500 MHz 69.55 26.16
1500-2000MHz 46.3 33.9