Do We Need Wireless Networks

wireless needs (work)
Do we need wireless? Wireless needs a lot of work! ;)
...Wireless networks:
“why, when & where” of WLANs
Marco Zennaro, [email protected]
& Carlo Fonda, [email protected]
RadioCommunications Unit
of the ICTP-ARPL
Trieste, Italy
Workshop on Wireless Technologies
for South Asian Countries
I
2
IT Pune, India
October 10 - 21, 2005
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Disclaimer
This is not a
(serious) lecture!
It’s just an
introduction to a
few arguments for
the lab activities.
And it gives brief
tentative answers
to basic questions...
Agenda
first, the big question(s)
then, let’s define the “battlefield”
( in our lab, what does “wireless” mean? )
finally, we will look at the schedule
in the meantime, we will discuss a
few questions about WLANs
during this hour, we will also try to indentify a
common background: skills and knowledge
about wireless, open source, networking, etc...
Wireless questions
The Big Question
fixed or mobile
technology: various issues
The Big Question
to wire or not to wire?
any difference between
wires and wireless?
...you’re saying we need
to go wireless, but...
why? when?
how can we decide?
to wire or not to wire?
any difference between
wires and wireless?
...you’re saying we need
to go wireless, but...
why? when?
how can we decide?
Poll: You & Wireless
You are interested in wireless computer
net working:
A) for teaching/academic purposes
B) for a practical implementation
C) nei ther of them
D) both of them
to wire or not to wire?
any difference between
wires and wireless?
...you’re saying we need
to go wireless, but...
why? when?
how can we decide?
Wired vs Wireless
Local Area Networking
•
Most of the time, users do not experience a
difference between using a (fixed) wireless
network and using a wired network.
•
To plan, design and install a wireless network is
quite different:
•
distance and line-of-sight
•
networks co-location, interferences
•
radiopropagation and environment
•
fast deployment, re-location and mobility
7 Km
Distance and Line-of-sight
The cost of a wireless
network increases
with the distance (and
with the bandwidth),
the relation is usually
non-linear.
A wireless network
connects one or more
locations that you can
visibly see.
Co-location and interferences
Co-location of more
networks usually affects
the performances.
Spectrum management
(frequencies and usage
coordination) is required
at both local and
international level (ITU).
Interferences may occur
from other e.m. sources.
Radiopropagation and environment
Performances of wireless
networks may be affected
by the properties of the
atmosphere (troposphere,
ionosphere), of the terrain,
of surrounding structures.
Worst case scenarios (i.e.
bad weather days) must
be considered.
Wireless network design
requires both technical
and scientific knowledge.
Fast deployment and re-location
Wireless networks can
be deployed in a very
short time, i.e. for:
disaster recovery networks
rapid changes of
communication needs
Wireless equipment
can be recycled and
re-located in a short
time, upon the need,
savi ng t i me and
previous investments.
Mobility
Wireless networks can
connect mobile users.
The fixed network
infrastructure is today:
what telephony has been for the past 50
years,
a primary communication service;
what a good library structure has been for
the past 500 years,
a primary knowledge source;
what an efficient road system has been for
the past 5000 years,
a primary escape way from
insulation:
Mobility is the next
step forward! (Now to
5 years? Or ... ???)
... fixed or mobile ?
Mobile Wireless Access:
mobile phones (ETACS, GSM...)
mobile data (1G, 2G, 3G, 4G...)
Fixed Wireless Access:
last mile problem / long links
leapfrog poor or expensive
telecom infrastructures
“difficult” environment
... fixed or mobile ?
Mobile Wireless Access:
mobile phones (ETACS, GSM...)
mobile data (1G, 2G, 3G, 4G...)
Fixed Wireless Access:
last mile problem / long links
leapfrog poor or expensive
telecom infrastructures
“difficult” environment
Poll: Fixed or Mobile
You are interested in:
A) mobile wireless (voice/data)
B) fixed wireless (access to Internet)
C) nei ther of them
D) both of them
33
DIGITAL MOBILE SUBSCRIBERS AND
INTERNET USERS (WORLDWIDE)
0
200
400
600
800
1000
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001
YEAR
U
S
E
R
S

(
M
i
l
l
i
o
n
s
)
Mobile Telephone Subscribers Internet Users
Source: ITU World Telecommunication Indicators Database.
fixed or mobile ?
In this lab, now, we will practice with
technologies for fixed wireless access:
it’s cheap
PnP easy
PTT-free
In future: ?
Wireless technology
fixed wireless technologies
38
WWAN
<15 km
802.20 (proposed)
IEEE STANDARDS VIEW OF WIRELESS
NETWORK TECHNOLOGIES
Source: International Telecommunications Union, “Birth of Broadband”, September 2003
MAN
<5 km
70 Mbit/s
802.16a/e
WiMAX
New standard for
Fixed broadband
Wireless. Trying to do
for MAN what Wi-Fi
did for LAN.
WLAN
<100 m
11-54 Mbit/s
802.11a/b, e, g
Wi-Fi
®
Includes 802.11a/b/g.
PAN
<10 m
~1 Mbit/s
802.15.1 (Bluetooth)
802.15.3 (UWB) *
802.15.4 (ZigBee)**
* UWB: 100 Mbit/s
** ZigBee: 250 kbps
fixed wireless technologies
38
WWAN
<15 km
802.20 (proposed)
IEEE STANDARDS VIEW OF WIRELESS
NETWORK TECHNOLOGIES
Source: International Telecommunications Union, “Birth of Broadband”, September 2003
MAN
<5 km
70 Mbit/s
802.16a/e
WiMAX
New standard for
Fixed broadband
Wireless. Trying to do
for MAN what Wi-Fi
did for LAN.
WLAN
<100 m
11-54 Mbit/s
802.11a/b, e, g
Wi-Fi
®
Includes 802.11a/b/g.
PAN
<10 m
~1 Mbit/s
802.15.1 (Bluetooth)
802.15.3 (UWB) *
802.15.4 (ZigBee)**
* UWB: 100 Mbit/s
** ZigBee: 250 kbps
Quiz: WiFi & WiMAX
Is i t true that...
A) WiMAX reaches a greater distance
compared to WiFi? (Yes/No/Maybe)
B) They both use the same modulation
but different power limi ts? (Y/N/M)
C) WiFi is an insecure technology? (Y/
N/M)
D) I’m not sure about the differences.
wireless networks were designed
(in 90es) for the LAN (indoor)
market, but in developing
countries WLANS are much
more useful outdoor, as MANs
(or even WANs), for distances
up to 10 Km (or 50 Km, or ...)
WLANs & WMANs
cost of wireless
the enormous success of this
technology has led to a dramatic
price reduction for the radio
devices:
>1000 US$ in 1992
<100 US$ in 2004
speed of wireless
the available data transfer rate
on the same radio channel
(bandwidth of 20 MHz) has
increased from 1 Mbps to 54
Mbps (even more Mbps for some non-
standard implementations)
wireless standards
wireless networking has grown
incredibly fast thanks to a wide
adoption of common standards:
802.11, 802.11a/b/g protocols
WiFi ™ certification
brand/model intercompatibility
wireless LANs
indoor/outdoor network
distribution among many clients
typical distance: 10 - 100 m
Point-to-MultiPoint structure:
master station (access point, AP)
client station (PCI card, PC card,
USB device, wireless bridge)
wireless MANs
used by ISPs (Point-to-MultiPoint)
typical distances: 1-5 Km
a large number of clients
coexistence problems (max. 3
non-overlapping channels)
line-of-sight, security issues,
remote management
Pietrosemoli 31
Fdcte DSSS
RedUla
Spike
Wireless RooI
wireless MANs
community/institution/company:
Point-to-Multipoint (mesh?)
Point-to-Point (larger distance,
less coexistence problems)
line-of-sight, security issues
radiolink planning
and design
Pietrosemoli 30
COR Aguada Norte
PA
FUNDACITE LAN
(NOC)
PA
PA
PA
LAN Switch/Hub
PC router
(OS Linux)
COR Pico Espejo
!"#"$%"
PA
9.15 Km
5.2 Km
64.33 Km
3.66 Km
Canagua Link
COR
Paramo deI Motor
Pietrosemoli 32
MARS: enlace desde
Pico Espejo. 4765 m
A la Hechicera 1800 m
5.8 GHz, 10 Mbps
!"#$%& '()*+,-.#$/0
1.+.&#/-02(&($*304!'125
Joint Venezuelan-German
project:
5.8 GHz, 16 km link
Pico Espejo. 4765 m
to Hechicera 1800 m
P2MP MANs
Point-to-Multipoint
Star topology, one AP, many stations
Omnidirectional antenna for AP
Directive antennas for stations
AP
STA
STA STA
P2MP MANs (cont.)
coexistence problem:
APs use omni antennas, so they may
interfere with other APs or stations
different channels can be used, but only
3 channels are non-overlapping
coordination is required among APs
2/13/04 Pietrosemoli 26
2/13/04 Pietrosemoli 24
Channel Overlapping
P2MP MANs (cont.)
Mesh topology
many nodes
complex
topology
dynamic
work in
progress!
P2P MANs (WANs)
wireless long distance links (<10 Km)
provide connectivity to remote sites
broadband (1, 2, 5, 11, 54 Mbps)
no monthly/traffic fee, no recurrent
costs (unlike leased lines from PPT)
require skills for planning and
installation (power budget)
Power Budget
2/13/04 Pietrosemoli 47
!"#$% "&$% '()*+,-$
Gt Gr
Tx Rx
At
Ar
Free Space Loss
Pt
Pr
dBm
km
Low-cost links?
It is possible to build inexpensive
long–distance radiolinks, with
old PCs, Linux OS, off–the–shelf
WiFi devices (sold for indoor),
home–made antennas:
200-500 US$ per links (less?)
skills are required, but you can
find plenty of information and
tutorials, just surfing the WWW
Buying antennas?
Buying antennas?
Antenna making
Meaning of “wireless”
Let’s summarize!
fixed wireless (WiFi)
unexpensive solution (WiFi)
(not WiMAX, for now)
standard, off-the-shelf (WiFi)
indoor for outdoor (mod WiFi)
P-t-P , P-t-MP, long links, mesh
DIY (antennas, APs)
Schedule for Workshop on Wireless Technologies for South Asian Countries (October 10 – 21,
2005):
Venue: Wireless Laboratory, International Institute of Information Technology, Pune-411057, India
DAY DATE/
Day
Session I
9.30 AM – 10.30 AM
Tea/Coffee
10.30 AM –
11.00 AM
Session II
11.00 AM – 12.00
noon
Session III
12.00 noon - 1
PM
Lunch
1 PM – 2
PM
Session III
2 PM – 3 PM (For
Oct 10, 2.00 PM –
3.30 PM)
Tea/Coffee
3.00 PM –
3.30 PM (For
Oct 10, 3.30
PM – 4.00
PM)
Session IV
3.30 PM – 5.30 PM
(For Oct 10, 4.00 PM –
5.30 PM)
1 Oct.
10Mon
Registration and Administrative Matters
(I
2
IT) Inauguration of the
Workshop
Review of Wireless
Communications
(RajeshS)
2
Oct.11
Tues
Antenna and Radio Wave
Propagation
(CarloF)
Mobile
Communications
(RavindraJ)
Internetworking
and Routing
Technologies
(BharatC)
Internetworking and
Routing
Technologies
(BharatC)
Networking Laboratory
(AjithK, VinayakP and
RA’s)
3 Oct.12
Wed
Dessera – a Indian Festival Holiday (Visit to Panchgani and Mahabaleshwar)
4
Oct.13
Thus
Linux
(TomasK/MarcoZ)
Linux Lab (TomasK,
AmitH, AjithK,
RA’s)
Linux Lab
(TomasK, AmitH,
AjithK, RA’s)
GSM/GPRS
Technologies
(VinayakP)
Basic Antennas Lab/dB
Math’s.
(MarcoZ, RA’s)
5 Oct.14 Fri
Wi-Fi Technologies
(TomasK)
Wi-Fi Hardware
Review
(TomasK)
Wi-Fi Lab
(TomasK, CarloF,
MarcoZ,
VinayakP, Ra’s)
Wi-Fi Lab
(TomasK, CarloF,
MarcoZ, VinayakP,
Ra’s)
Wi-Fi Lab
(TomasK, CarloF,
MarcoZ, VinayakP, Ra’s)
6
Oct.15
Sat
Visit to Giant Meter wave Radio Telescope (GMRT), Narayangaon
7
Oct.16
Sun
Open
Co-sponsored by:
Pune Subsection
International Institute of Information Technology, Hinjawadi, Pune – 411057, India (www.isquareit.ac.in)
Laboratory schedule
why is it important for wireless?
network device (router, gw,...)
software AP, firmware upgrade
wireless troubleshooting tools
bandwidth optimization
OpenSource & Linux
why is it important for wireless?
network device (router, gw,...)
software AP, firmware upgrade
wireless troubleshooting tools
bandwidth optimization
OpenSource & Linux
Poll: You & Linux
You know:
A) how to install and setup a Linux PC
B) how to manage text files in Linux
C) what Linux is, but not how to use i t
D) I don’t know anything about Linux
Networking
TCP/IP
routing
advanced networking
(optimization, etc...)
Networking
TCP/IP
routing
advanced networking
(optimization, etc...)
Poll: Net working
You know:
A) well enough about the 7 OSI layers
B) how to spli t a net work in subnets
C) how to configure TCP/IP on your PC
D) not very much about net working
WiFi networks
AP configuration
architectures of WLANs
firmware upgrade
power budget
long distance link
Antenna DIY
different antennas
measurements on antennas
using a Spectrum Analyzer
making of two antennas
Antenna DIY
different antennas
measurements on antennas
using a Spectrum Analyzer
making of two antennas
Quiz: Antennas
True or false:
A) an antenna can be good for
transmi tting and bad for recei ving
B) a parabolic grid recei ve only half
signal compared wi th a parabolic dish
C) TV antennas can be used for WiFi
D) antennas are mysterious things
Thank you
for your attention!
Any question?