Report Project 1

ABSTRACT
Current electrical billing system in Pakistan is manual and there are a lot of complaints with the billing system. Corruption and client’s dissatisfaction is at peak. Number of complaints regarding over charging, error full meter reading and the corruption is increasing day by day. So it’s the need to the hour to develop and efficient and effective method of billing system. An automatic way of meter reading and transmitting it to the central office can cure the problem. This project highlights the use of wireless technology (SMS in this case) for remote acquisition of data from different sites. Wireless technology is fastest growing field of the modern world which finds its application in many different technical fields. The trend of wireless telemetry is now replacing the existing analog electric meters in many countries. Wireless technologies such as GSM & GPRS play a key role to facilitate the remote reading of electricity meters. This project also encompasses the same field. The core idea of this project is monitoring the electricity meters remotely just by using GSM technology, thus making it possible to save time as well as money. Keeping in mind the versatility of the project a lot of advancements can be made in this project thus making the system more efficient and advanced. In chapter 7, proposal for future advancements has been discussed in detail.

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SCOPE OF THE PROJECT
In this technology world, electricity has become one of the many necessities of our daily life. Everywhere in homes, offices, factories and markets, the use of electric energy has been increased. It has become a great challenge for electric supply company to cope with this increasing electric energy demand every where in the world. Every country is trying to increase its electric energy generation by installing more and more hydro, nuclear and fossil fuel electric power plants. In this scenario the efficient use of electric energy is very important to save this valuable resource. The efficient use of electric energy is highly dependant on energy metering. The electromechanical meter is the most common way to measure energy usage employing analog methods. The analog meter’s main disadvantage of electric meter is that it does not provide with the information to make electricity utilization more efficient. The purpose of this project is to design a way to get analog readings from the analog meter that can provide with more parameters about the consumption of electric energy to make utilization of electric energy more efficient. The meter measures the energy consumed by a consumer and sends that data to a main computer via mobile. The solution is micro-controller based. This provides great flexibility to measure the many desired features of electricity utilization to make it more efficient.

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PROJECT PICTURE

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TABLE OF CONTENTS
i. ii. iii. iv. v. Front page - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -1 Abstract - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3 Scope Of the Project - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -4 Acknowledgements - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 5 Project Picture - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -6

CHAPTER 1 1. Background And Introduction - - - - - - - - - - - - - - - - - - - - - - - - - -9

1.1 Purpose - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -10 1.2 Project Summary - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 10 1.3 What is Signal - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 10 1.3.1 Why Digital - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 11 1.4 What is Energy Meter - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -11 1.5 Wireless Telemetry - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 11 1.6 Automated Meter Reader - - - - - - - - - - - - - - - - - - - - - - - - - - - - -11 1.7 - Cellular Communication-An Overview - - - - - - - - - - - - - - - - - - - 12 1.7.1 Short messaging service - - - - - - - - - - - - - - - - - - - - - - - - - - -12 1.7.2 SMS subscriptions and hardware - - - - - - - - - - - - - - - - - - - - 12 1.8- Steps towards project- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 13 1.8.1 Acquisition of data from digital meter - - - - - - - - - - - - -- - - -13 1.8.2 Interfacing mobile phone with microcontroller - - - - - - - - - - 14 1.8.3 Interfacing mobile phone with computer - - - - -- - - - - - - - - -15 1.8.4 Establishment of a server - - - - - - - - - - - - - - - - - - - - - - - - - -15 1.8.5 Implementation of the project - - - - - - - - - - - - - - - - - - - - - - -15 1.8.6 Cost of the project in PKRS - - - - - - - - - - - - - - - - - - - - - - - - -16

CHAPTER 2 2. Wireless Telemetry - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -17 2.1 Wireless telemetry - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -18 2.2 Automated meter reader - - - - - - - - - - - - - - - - - - - - - - - - - - - - 19 3 Introduction to GSM - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 22
3.1 Cellular Communication - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 23 3.2 Basic components of GSM - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 23 3.2.1 GSM Network Overview - - - - - - - - - - - - - - - - - - - - - - - - - - - 23 3.2.2 Mobile Station (MS) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 25 3.2.3 Base Station System (BSS) - - - - - - - - - - - - - - - - - - - - - - - - - 28 3.3 Transcoder (XCDR) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 32 3.4 Network Switching System - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- 34 3.5 Operations and Maintenanc0e System - - - - - - - - - - - - - - - - - - - - - - 42 3.6 The Network in Reality - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 45 4 Introduction to Microcontroller - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -47 4.1 What is a Microcontroller - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -48 4.1.1 Arduino - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -51 4.1.2 Platforms from Parallax, Inc - - - - - - - - - - - - - - - - - - - - - - - - - - 51 4.1.3 PICAXE - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 51 Design & Fabrication of GSM Based Electric Energy Meter

CHAPTER 3

CHAPTER 4

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4.1.4 ZX-24, ZX-40, ZX-44 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 52 4.2 PIC Microcontroller - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - 52 4.2.1 Core Architecture of the 8-bit CPUs - - - - - - - - - - - - - - - - - - - - - 53 4.2.2 Data Space (RAM) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 53 4.2.3 Code Space - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - 54 4.2.4 Word Size - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 54 4.2.5 Stacks - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 54 4.2.6 Instruction Set - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -55 4.3 High-Performance RISC CPU - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -55 4.4 Features - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 56 4.4.1 Special Microcontroller Features - - - - - - - - - - - - - - - - - - - - - - -56 4.4.2 Peripheral Features - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 57 4.4.3 Analog Features - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -57

CHAPTER 5 5 Software Tools - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -58 5.1 Visual Basic - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 59 5.1.1 Language Features - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 60 5.2 Microsoft Office Access - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -61 5.2.1 Features - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 61 5.2.2 Uses - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 62 5.3 Crystal Report - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 62 5.3.1 Creating Reports - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -62 5.3.2 Running Reports Locally - - - - - - - - - - - - - - - - - - - - - - - - - - - 63 6 Hardware Details- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- 64
6.0 Hardware Details- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -65 6.1 Analog Energy Meter- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 65 6.1.1 Overview- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 65 6.1.2 Electromechanical meters- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -65 6.1.3 Technology - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - 66 6.1.4 Working- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 67 6.1.5 Accuracy- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 68 6.2 Opto Coupler / Opto Isolator- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 68 6.3 Power Supply- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 69 6.4 LC circuit- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 69 6.5 Voltage Regulator (LM 311) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 70 6.6 LCD - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -70

CHAPTER 6

CHAPTER 7 7 Future Advancements in Project - - - - - - - - - - - - - - - - - - - - - - - - - - - - -71 7.1 Future Advancement in Project - - - - - - - - - - - - - - - - - - - - - - - - - - - 72 7.1 Duplex Communication - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 72 7.2 Power Shut Down - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 73 7.3 Data Storage - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 74 7.4 Composite/Multi phases meter - - - - - - - - - - - - - - - - - - - - - - - - - - - -75 7.5 Networking - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 76 APPENDICES
Appendix I - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -77 Appendix II - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 84 Appendix III - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - -- - - 85 Design & Fabrication of GSM Based Electric Energy Meter

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Acronyms- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 94 References - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 96

CHAPTER NO.1 BACKGROUND AND INTRODUCTION

Important Points: • Purpose of the project • Scope of the project • Overview of Wireless telemetry
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• Introduction to GSM network • Acquisition of data from digital meter • Project Budget
1.1 - PURPOSE: Currently WAPDA has installed magnetic coil type mechanical energy meters. There are a lot of complaints regarding electrical billing system of WAPDA from the valued customers. The purpose of the project is to devise a better way for metering so that complaints can be removed. Corruption involved in the billing system can also be eliminated.

1.2 - PROJECT SUMMARY:
The task in this project is to devise an efficient way for measuring the energy consumed by a consumer and transmitting it to the central office. Phase-I is to get analog readings from an analog meter and convert it into digital by attaching color sensors and then interfacing of the sensor with the microcontroller. Mobile phone is programmed so that it generates SMS after every two minutes and sends it to the central office. Another mobile phone is interfaced with a computer and a server is established. There an operator sitting at the pc receives SMS containing the meter reading of that time after every two minutes.

1.3 - WHAT IS A SIGNAL:
A signal is a piece of information in a sinusoidal wave form. A signal can be analog, digital or hybrid. A signal that has continuously varying voltages, frequencies, and phases is called an analog signal. A type of signal that encodes voice, video, or data transmitted over wire or through the air, and is commonly represented as an oscillating wave. An analog signal can take any value in a range and changes smoothly between values. A digital signal is a transmission signal that carries information in a discontinuous stream of on/off pulses. A way of sending voice, video, or data that reconstructs the signals using binary codes (1s and 0s) for transmission through wire, fiber optic cable, videoconference, or over air techniques. Digital audio/video signals represented by discrete variations (in voltage, frequency,
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amplitude, location, etc.) can be transmitted faster and more accurately than analog signals.

1.3.1 - Why Digital?
Digital signals are not subject to the interference, signal loss, and noise as compared to analog signal. It can be reconstructed into a perfect replica of the original source. Digital data can be encrypted to provide some measure of protection against unwanted viewing or listening. They have low cost.

1.4 - WHAT IS AN ENERGY METER?
An electric meter or energy meter is a device that measures the amount of electric energy supplied to a residence or business. The person that uses the electricity is called the customer of an electric company. The most common unit of measurement on the electricity meter is the kilowatt-hour which is equal to the amount of energy used by a load of one kilowatt over a period of one hour, or 3,600,000 joules. Energy meters can be both analog and digital.

1.5 - WIRELESS TELEMETRY
Wireless telemetry can be defined as machine-to-machine communications via a radio link. This is often the transfer of data from sensors for remote monitoring or data collation purposes. Typical applications include: • • • • • • Building alarms Vehicle and boat alarms Remote meter reading Environmental applications, such as weather stations and Border access control Monitoring of water, gas or oil pipelines/facilities

earthquake status monitoring

1.6 - AUTOMATED METER READER
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Automated Meter Reading is the technology of collecting data from water meters or energy meters and transferring that data to central database for billing and analyzing. It has following benefits and uses: • • AMR reduces the need for meter reader to gather meter reading each month AMR technology is used to improve customer service

1.7 - CELLULAR COMMUNICATION - AN OVERVIEW:
A cellular telephone system links mobile station (MS) subscribers into the public telephone system or to another cellular system’s MS subscriber. Information sent between the MS subscriber and the cellular network uses radio communication. This removes the necessity for the fixed wiring used in a traditional telephone installation. Due to this, the MS subscriber is able to move around and become fully mobile, perhaps traveling in a vehicle or on foot. 1.7.1 - Short Messaging Service: The Short Message Service (SMS) allows text messages to be sent and received to and from mobile telephones. The text can be comprised of words or numbers or an alphanumeric combination. The SMS is a store and forward service ---short messages are not sent directly from sender to recipient, but through an SMS Center 1.7.2 - SMS Subscriptions and Hardware: • • A subscription to a mobile telephone network that supports SMS. Use of SMS must be enabled for that user (automatic access to the

SMS is given by some mobile network operators, others charge a monthly subscription and require a specific opt-in to use the service). • • • Mobile phone or GSM modem that supports SMS. Knowledge of how to send or read a short message using their A destination to send a short message to, or receive a message from.

specific model of mobile phone or GSM modem.

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1.8 - STEPS TOWARDS PROJECT:
Following will be the steps towards project • • • • • • • • Simulation Model To get digital readings from electromechanical meter To interface meter with the microcontroller To interface microcontroller with the mobile Establishment of a server To transmit readings to the server Development of database for billing Project Report

Details of each part will be discussed in the subsequent pages. 1.8.1 - Acquisition of Data from Digital Meter PROBLEM • • Current and voltage is analog by default There fore they must be converted in to digital form

SOLUTION # 1 • • • • Open the meter. Put a cut at its plate and attached an IR Tx n Rx on top and bottom of it. As the plate rotates, on each cut, we will get an IR signal at the output. Thus analog information is converted in to digital one

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SOLUTION # 2 • • • • Attach color sensors at the top of the meter. Detect the black spot on the plate. Interface the sensor with microcontroller (preferably pic ). Microcontroller is programmed so that it increments one in a register each time the IR signal arrives. SOLUTION # 3: The 3rd approach is to use current transformers and potential transformers. With the help these two transformers, we can calculate the energy consumed by a customer. With the help of potential transformer, voltage can be obtained and with the help of current transformer, current can be obtained. Suppose it is required to determine the energy consumed by a house hold, we can do it in the following way. • • • • Voltage and current are sampled at an appropriate rate through Analog to Digital converter From the plot of these samples phase difference between the current and voltage is determined by using some computer tool like MATLAB. From the phase difference, power factor is determined. Finally real power, imaginary power is determined in the micro-controller.

1.8.2 - Interfacing Mobile Phone with Microcontroller:
• • It’s a serial interface. Programming of the mobile phone from the microcontroller so that it may generate a SMS each time.

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INTERFACE

FIG 1.1: Interfacing of mobile phone with microcontroller

1.8.3 - Interfacing mobile Phone with Computer:
• • Interfacing of another mobile phone with a computer. It’s a serial interface directly with the data cable.

INTERFACE

FIG 1.2: Interface of mobile phone with computer 1.8.4 - Establishment of Server: • • • Establishment of the server at a pc is in visual basic. The operator receives the SMS containing the meter reading of that time after two minutes. LCD is interfaced to the microcontroller. 1.8.5 - Implementation of the Project: Final step is to implement the project. implementation of the project. Following hard wave was used for the

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• • • • • • • • • •

2 Mobile phone Energy meter PIC Programmer 2 Data cables PIC 16F877A Microcontroller LCD Breadboard Optocoupler Shimmit trigger Resistors, Capacitors, Inductors, Vero board, Soldering Machine

1.8.6 - Cost of the Project in PKRS:

COMPONENTS Energy Meter Opto-coupler Power Supply Mobile PIC 16F877A Ziff Socket Miscellaneous Total

PRICE 850 50 100 900 240 90 200 2430

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CHAPTER NO.2 WIRELESS TELEMETRY

Important Points: • Wireless Telemetry • Automatic Meter Reader
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2.1 - WIRELESS TELEMETRY
Wireless telemetry can be defined as machine-to-machine communications via a radio link. This is often the transfer of data from sensors for remote monitoring or data collation purposes. Typical applications include: • • • • • • Building alarms Vehicle and boat alarms Remote meter reading Environmental applications, such as weather stations and Border access control Monitoring of water, gas or oil pipelines/facilities

earthquake status monitoring

It is often tempting to consider addressing a telemetry requirement with a standardbased solution such as GSM/GPRS or 3G. Whilst these established standards do offer well defined hardware and software specifications and have an existing network infrastructure, they have not been optimized for the specific telemetry application under consideration. The power consumption, terminal equipment cost, data transport cost and/or data rate are unlikely to be all optimal for any given application. Other standard-based, wireless data transfer solutions such as Bluetooth, DECT or 802.11b may offer more attractive cost models but may fall short in other ways such as achievable range or battery life. Key requirements of many of the telemetry applications mentioned above include: • • • • • • Low unit cost Low data transport costs Long battery life (low operating power) Adequate range Low/moderate data rates A custom-designed, application-specific telemetry system should result in the optimum solution for a given application because the correct trade-offs

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between the conflicting requirements can be made during the design process. In the case of the remote utility meter reading system, a low cost radio transmitter is fitted to or integrated with existing metering equipment. An interface to that equipment allows local data storage shows the remote customer premises equipment for both an electricity meter and a gas meter. Data is transmitted from the remote terminal to a base station with a subsequent back-haul link to a central server. The rate of transmission from the meter is programmable from several times per hour to daily or even weekly. The adoption of a custom telemetry solution allows the system architecture and radio interface technology to be tailored to minimize the cost, complexity and power consumption of the remote unit at the meter. Although it is essential to keep the cost of the remote unit very low, it is also necessary to ensure that the communications range of the radio link is adequate in order to keep the infrastructure deployment costs down. The key to achieving these goals is the development of a sophisticated, custom radio communications protocol and the use of digital signal processing in the base station receiver. The resulting system supports packet transmissions of nominally 2kbps with payloads typically in the range 32-64 bytes. The remote unit is a narrow band, phase-modulated transmitter operating on a randomized time and frequency basis. The base station receiver utilizes an advanced, wideband multi channel DSP architecture able to decode up to forty simultaneously received signals. A single base station is able to support several thousand remote terminals.

2.2 - AUTOMATED METER READER
Using wireless radio transmitters, AMR remotely reads customer meters and then transfers the data into the billing system. AMR will reduce the need for meter readers to manually gather utility meter readings each month. Many utilities are using AMR as a way to improve customer service and control their meter reading costs, especially in areas with fenced yards, dogs, landscaping and other issues that make accessing meters difficult or unsafe. Benefits include:


Improved customer service, which includes:
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o

Minimizing the need to access customer property to read Reducing customer complaints and damage claims Call resolution improvement – billing complaint calls will

meters
o

resulting from monthly visits to customer site
o

be handled more quickly due to availability of more frequent meter readings
o

No need for customer to read their own meters due to

meter access issues Controlled meter reading costs Enhanced customer convenience Fewer employee injuries, especially in areas with fenced yards, dogs Improved billing accuracy A reduction in operational costs

  

and landscaping
 

There are several AMR technologies in today's market, ranging from walk-by, driveby, fixed networks to telemetry-based systems. We are planning to deploy a wireless fixed network system. There are three components: • • • Customer Utility Meter - with wireless radio transmission Data Relay Box - usually attached to a street light Data collection through a telecom transmission, management

and billing system As meters get older they may become less accurate and need to be replaced, and it makes good business sense to upgrade to this new technology at this time. Through the reduced need for on-site manual meter readings and other efficiencies, the system is expected to pay for itself within approximately 10 years of installation. Only meter readings and meter or module numbers are transmitted. Personal customer information will not be transmitted. We use wireless packet data technology to keep information private and secure. Wireless packet data was
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originally developed by the U.S. military for secure communications. Features of the AMR electric endpoint modules include built-in power outage notification, reverse rotation detection, magnetic tamper detection, power restoration notification and redundant transmissions. The transmitting devices operate in compliance with FCC regulations to avoid interference with other electronic devices. The only significant change to utility service will be that meter readers will not need to visit the property monthly to collect the meter readings. Service personnel may visit the meter periodically to confirm proper operation or perform routine maintenance. The primary objective of this project is to design a system that monitors the readings of electricity meters at the control room without meter readers visits. - A fine solution for the electric power supplying companies who wants to access and record the power consumption information at consumer premises from remote distances. Wireless technology is widely used across different household appliances, and it is highly accepted due to the mobility it brings for the owners. The current range of the wireless doorbell cannot fulfill the demand for some people nowadays as modern citizens are now obliged to be more flexible and highly mobilized for maximizing their efficiency. Longer-range remote electrical goods have become a necessary trend for the next generation of household appliances as the market demands higher mobility. Accessing the cellular network provides the essential range for this thesis project. Constructing wireless doorbell system, that is GSM/GPRS network compatible, would bring modern households into an extended life style.

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CHAPTER NO.3 INTRODUCTION TO GSM

Important Points: • Basic concepts of GSM • Basic components of GSM • Network switching system
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• Network in reality
3.1 - CELLULAR COMMUNICATION
A cellular telephone system links mobile station (MS) subscribers into the public telephone system or to another cellular system’s MS subscriber. Information sent between the MS subscriber and the cellular network uses radio communication. This removes the necessity for the fixed wiring used in a traditional telephone installation. Due to this, the MS subscriber is able to move around and become fully mobile, perhaps traveling in a vehicle or on foot.

3.2 - BASIC COMPONENTS OF GSM 3.2.1 - GSM Network Overview
The diagram below shows a simplified GSM network. Each network component is designed to communicate over an interface specified by the GSM standards. This provides flexibility and enables a network provider to utilize system components from different manufacturers. For example Motorola Base Station System (BSS) equipment may be coupled with an Ericsson Network Switching System. The principle component groups of a GSM network are  The Mobile Station (MS) This consists of the mobile telephone, fax machine etc. This is the part of the network that the subscriber will see.  The Base Station System (BSS) This is the part of the network which provides the radio interconnection from the MS to the land-based switching equipment.  The Network Switching System This consists of the Mobile services Switching Centre (MSC) and its associated System-control databases and processors together with the required interfaces. This is the part which provides for interconnection between the GSM network and the Public Switched Telephone Network (PSTN).

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Fig 3.1: Showing architecture of GSM network

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 The Operations and Maintenance System This enables the network provider to configure and maintain the network from a central location. In the text to follow each component group is discussed in detail

3.2.2 - Mobile Station (MS)
The MS consists of two parts,  Mobile Equipment (ME)  Subscriber Identity module (SIM) (An electronic ‘smart card’ ) The ME is the hardware used by the subscriber to access the network. The hardware has an identity number associated with it, which is unique for that particular device and permanently stored in it. This identity number is called the International Mobile Equipment Identity (IMEI) and enables the network operator to identify mobile equipment which may be causing problems on the system. The SIM is a card which plugs into the ME. This card identifies the MS subscriber and also provides other information regarding the service that subscriber should receive. The subscriber is identified by an identity number called the International Mobile Subscriber Identity (IMSI). Mobile Equipment may be purchased from any store but the SIM must be obtained from the GSM network provider. Without the SIM inserted, the ME will only be able to make emergency calls. By making a distinction between the subscriber identity and the ME identity, GSM can route calls and perform billing based on the identity of the ‘subscriber’ rather than the equipment or its location.  Mobile Equipment (ME) The ME is the only part of the GSM network which the subscriber will really see. There are three main types of ME, these are listed below:  Vehicle Mounted These devices are mounted in a vehicle and the antenna is physically mounted on the outside of the vehicle.

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 Portable Mobile Unit This equipment can be handheld when in operation, but the antenna is not connected to the handset of the unit.  Hand portable Unit This equipment comprises of a small telephone handset not much bigger than a calculator. The antenna is be connected to the handset. The ME is capable of operating at a certain maximum power output dependent on its type and use. These mobile types have distinct features which must be known by the network, for example their maximum transmission power and the services they support. The ME is therefore identified by means of a Classmark. The classmark is sent by the ME in its initial message. Class Mark The following pieces of information are held in the classmark  Revision Level

Identifies the phase of the GSM specifications that the mobile complies with.  RF Power Capability – The maximum power the MS is able to transmit, used for power control and handover preparation. This information is held in the mobile power class number. Ciphering Algorithm



Indicates which ciphering algorithm is implemented in the MS. There is only one Algorithm (A5) in GSM phase 1, but GSM phase 2 specifies different algorithms (A5/0–A5/7). Frequency Capability



Indicates the frequency bands the MS can receive and transmit on. Currently all GSM MSs use one frequency band, in the future this band will be extended but not all MSs will be capable of using it. Short Message Capability
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

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Indicates whether the MS is able to receive short messages or not.

POWER CLASS 1 2 3 4 5

POWER OUTPUT(Watts) 20(Not Used Now) 8 5 2 0.8

 Subscriber Identity Module (SIM) The SIM as mentioned previously is a “smart card” which plugs into the ME and contains information about the MS subscriber hence the name Subscriber Identity Module. The SIM contains several pieces of information:  International Mobile Subscriber Identity (IMSI) This number identifies the MS subscriber. It is only transmitted over the air during initialization.  Temporary Mobile Subscriber Identity (TMSI) This number identifies the subscriber, it is periodically changed by the system management to protect the subscriber from being identified by someone attempting to monitor the radio interface.  Location Area Identity (LAI) Identifies the current location of the subscriber.  Subscriber Authentication Key (Ki) This is used to authenticate the SIM card.  Mobile Subscriber International Services Digital Network

(MSISDN) Number

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This is the telephone number of the mobile subscriber. It is comprised of a country code, a network code and a subscriber number. Most of the data contained within the SIM is protected against reading (Ki) or alterations (IMSI). Some of the parameters (LAI) will be continuously updated to reflect the current location of the subscriber. The SIM cards, and the high degree of inbuilt system security, provide protection of the subscriber’s information and protection of networks against fraudulent access. SIM cards are designed to be difficult to duplicate. The SIM can be protected by use of Personal Identity Number (PIN) password, similar to bank/credit charge cards, to prevent unauthorized use of the card. The SIM is capable of storing additional information such as accumulated call charges. This information will be accessible to the customer via handset/keyboard key entry. The SIM also executes the Authentication Algorithm.

Fig 3.2: Actual Size of SIM

Fig 3.3: Mini SIM card

3.2.3 - Base Station System (BSS)
The GSM Base Station System is the equipment located at a cell site. It comprises a combination of digital and RF equipment. The BSS provides the link between the MS and the MSC. The BSS communicates with the MS over the digital air interface and with the MSC via 2 Mbit/s links.
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The BSS consists of three major hardware components:  The Base Transceiver Station – BTS The BTS contains the RF components that provide the air interface for a particular cell. This is the part of the GSM network which communicates with the MS. The antenna is included as part of the BTS.  The Base Station Controller – BSC The BSC as its name implies provides the control for the BSS. The BSC communicates directly with the MSC. The BSC may control single or multiple BTSs.  The Transcoder – XCDR The transcoder is used to compact the signals from the MS so that they are more efficiently sent over the terrestrial interfaces. Although the transcoder is considered to be a part of the BSS, it is very often located closer to the MSC. The transcoder is used to reduce the rate at which the traffic (voice/data) is transmitted over the air interface. Although the transcoder is part of the BSS, it is often found physically closer to the NSS to allow more efficient use of the terrestrial links.

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Fig 3.4: Showing Transcoder and BTS link  Base Transceiver Station – BTS The BTS provides the air interface connection with the MS. It also has a limited amount of control functionality which reduces the amount of traffic passing between the BTS and BSC. The functions of the BTS are shown opposite. Each BTS will support 1 or more cells.  Base Station Controller (BSC) As previously mentioned, the BSC provides the control for the BSS. Any operational information required by the BTS will be received via the BSC. Likewise any information required about the BTS (by the OMC for example) will be obtained by the BSC. The BSC incorporates a digital switching matrix, which it uses to connect the radio channels on the air interface with the terrestrial circuits from the MSC. The BSC switching matrix also allows the BSC to perform “handovers” between radio channels on BTSs, under its control, without involving the MSC.

BSS Functionality

Control

BSS Functionality

Control

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Terrestrial Channel Management Channel Allocation Radio Channel Management Channel Configuration Management Handover Control Frequency Hopping Traffic Channel Management

BSC BSC BSC BSC BSC BSC/BTS BSC/BTS

Encryption Paging Control Channel Management Measurement Reporting Channel Coding/Decoding Timing Advance Idle Channel Observation

BSC/BTS BSC/BTS BSC/BTS BTS BTS BTS BTS

Where the BSC and BTS are both shown to control a function, the control is divided between the two, or may be located wholly at one.

SUMMARY OF THE FUNCTIONS OF BSC AND BTS BSC Control one or more BTS Switches traffic and signaling to\from the BTS and MSC Connects terrestrial channels and circuits on air interface Controls handovers performed by BTS under its control  BSS Configurations As we have mentioned, a BSC may control several BTSs, the maximum number of BTSs which may be controlled by one BSC is not specified by GSM. Individual manufacturer’s specifications may vary greatly. The BTSs and BSC may either be located at the same cell site “co-located”, or located at different sites “Remote”. In reality most BTSs will be remote, as there are many more BTSs than BSCs in a network. Another BSS configuration is the daisy chain. A BTS need not communicate directly with the BSC which controls it, it can be connected to the BSC via a chain
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BTS Contains RF hardware Limited control functionality Supports 1 or more cells

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of BTSs. Daisy chaining reduces the amount of cabling required to set up a network as a BTS can be connected to its nearest BTS rather than all the way to the BSC. Problems may arise when chaining BTSs, due to the transmission delay through the chain. The length of the chain must, therefore, be kept sufficiently short to prevent the round trip speech delay becoming too long. Other topologies are also permitted, including stars and loops. Loops are used to introduce redundancy into the network, for example if a BTS connection was lost, the BTS may still be able to communicate with the BSC if a second connection is available.

Fig 3.5: Showing BSS configuration
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3.3 - TRANSCODER (XCDR) The Transcoder (XCDR) is required to convert the speech or data output from the MSC (64 kbit/s PCM), into the form specified by GSM specifications for transmission over the air interface, that is, between the BSS and MS (64 kbit/s to 16 kbit/s and vice versa) The 64 kbit/s Pulse Code Modulation (PCM) circuits from the MSC, if transmitted on the air interface without modification, would occupy an excessive amount of radio bandwidth. This would use the available radio spectrum inefficiently. The required bandwidth is therefore reduced by processing the 64 kbit/s circuits so that the amount of information required to transmit digitized voice falls to a gross rate of 16 kbit/s. The transcoding function may be located at the MSC, BSC, or BTS. The content of the 16 kbit/s data depends on the coding algorithm used. There are two speech coding algorithms available and selecting which one to use depends on the capabilities of the mobile equipment and the network configuration. The Full Rate speech algorithm is supported by all mobiles and networks. It produces 13 kbit/s of coded speech data plus 3 kbit/s of control data which is commonly referred to as TRAU data (Transcoder Rate Adaption Unit). The TRAU data on the downlink will be used by the BTS and therefore removed from the 13 k of speech data before transmission on the air interface. the 13 kbit/s of speech data is processed at the BTS to form a gross rate of 22.8 kbit/s on the air interface which includes forward error correction. In the uplink direction the BTS adds in TRAU data which will be used by the transcoder. Enhanced Full Rate is an improved speech coding algorithm and is only supported by Phase 2+ mobiles and is optional in the Network. It produces 12.2 kbit/s from each 64 kbit/s PCM channel. The TRAU data in this case is made up to 3.8 kbit/s to keep the channel rate to and from the BTS at 16 kbit/s as for Full Rate. As with Full Rate the TRAU data is used at the BTS and Transcoder. For data transmissions the data is not transcoded but data rate adapted from 9.6 kbit/s (4.8 kbit/s or 2.4 kbit/s may also be used) up to a gross rate of 16 kbit/s for transmission over the terrestrial interfaces, again this 16 kbit/s contains a 3 kbit/s TRAU. As can be seen from the diagram opposite, although the reason for transcoding was to reduce the data rate over the air interface, the number of terrestrial links is also reduced approximately on a 4:1 ratio.
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Fig 3.6: Showing C-7 Signaling

3.4 - NETWORK SWITCHING SYSTEM
The Network Switching System includes the main switching functions of the GSM network. It also contains the databases required for subscriber data and mobility management. Its main function is to manage communications between the GSM network and other telecommunications networks. The components of the Network Switching System are listed below:  Mobile Services Switching Centre – MSC  Home Location Register – HLR  Visitor Location Register – VLR  Equipment Identity Register – EIR
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 Authentication Centre – AUC  InterWorking Function – IWF  Echo Canceller – EC In addition to the more traditional elements of a cellular telephone system, GSM has Location Register network entities. These entities are the Home Location Register (HLR), Visitor Location Register (VLR), and the Equipment Identity Register (EIR). The location registers are database-oriented processing nodes which address the problems of managing subscriber data and keeping track of a MSs location as it roams around the network. Functionally, the Interworking Function and the Echo Cancellers may be considered as parts of the MSC, since their activities are inextricably linked with those of the switch as it connects speech and data calls to and from the MSs.  MOBILE SERVICES SWITCHING CENTRE (MSC) The MSC is included in the GSM system for call-switching. Its overall purpose is the same as that of any telephone exchange. However, because of the additional complications involved in the control and security aspects of the GSM cellular system and the wide range of subscriber facilities that it offers, the MSC has to be capable of fulfilling many additional functions.

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Fig 3.7: Showing Network Switching System The MSC will carry out several different functions depending upon its position in the network. When the MSC provides the interface between the PSTN and the BSSs in the GSM network it will be known as a GATEWAY MSC. In this position it will provide the switching required for all MS originated or terminated traffic. Each MSC provides service to MSs located within a defined geographic coverage area, the network typically contains more than one MSC. One MSC is capable of supporting a regional capital with approximately one million inhabitants. An MSC of this size will be contained in about half a dozen racks. The functions carried out by the MSC are listed below:  Call Processing Includes control of data/voice call setup, inter-BSS and inter-MSC handovers and control of mobility management (subscriber validation and location).  Operations and Maintenance Support Includes database management, traffic metering and measurement, and a
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man–machine interface.  Internetwork Interworking Manages the interface between the GSM network and the PSTN.  Billing Collects call billing data.  Home Location Register (HLR) The HLR is the reference database for subscriber parameters. Various identification numbers and addresses are stored, as well as authentication parameters. This information is entered into the database by the network provider when a new subscriber is added to the system. The HLR database contains the master database of all the subscribers to a GSM PLMN. The data it contains is remotely accessed by all the MSCs and the VLRs in the network and, although the network may contain more than one HLR, there is only one database record per subscriber – each HLR is therefore handling a portion of the total subscriber database. The subscriber data may be accessed by either the IMSI or the MSISDN number. The data can also be accessed by an MSC or a VLR in a different PLMN, to allow inter-system and inter-country roaming. HLR contains the following information  Subscriber ID(IMSI & MSISDN)  Current subscriber VLR  Supplementary services subscribed to  Supplementary services number(e.g current forwarding number)  Subscriber status(Registered or Deregistered)  Authentication key and AUC functionality  Mobile subscriber roaming number  Visitor Location Register (VLR)

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The VLR contains a copy of most of the data stored at the HLR. It is, however, temporary data which exists for only as long as the subscriber is “active” in the particular area covered by the VLR. The VLR database will therefore contain some duplicate data as well as more precise data relevant to the subscriber remaining within the VLR coverage. The VLR provides a local database for the subscribers wherever they are physically located within a PLMN, this may or may not be the “home” system. This function eliminates the need for excessive and time-consuming references to the “home” HLR database. The additional data stored in the VLR is listed below: Mobile status (busy/free/no answer etc.). Location Area Identity (LAI). Temporary Mobile Subscriber Identity (TMSI). Mobile Station Roaming Number (MSRN).  Location Area Identity Cells within the Public Land Mobile Network (PLMN) are grouped together into geographical areas. Each area is assigned a Location Area Identity (LAI), a location area may typically contain 30 cells. Each VLR controls several LAIs and as a subscriber moves from one LAI to another, the LAI is updated in the VLR. As the subscriber moves from one VLR to another, the VLR address is updated at the HLR.  Temporary Mobile Subscriber Identity The VLR controls the allocation of new Temporary Mobile Subscriber Identity (TMSI) numbers and notifies them to the HLR. The TMSI will be update frequently, this makes it very difficult for the call to be traced and therefore provides a high degree of security for the subscriber. The TMSI may be updated in any of the following situations: o Call setup. o On entry to a new LAI. o On entry to a new VLR.

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 Mobile Subscriber Roaming Number As a subscriber may wish to operate outside its “home” system at some time, the VLR can also allocate a Mobile Station Roaming Number (MSRN). This number is assigned from a list of numbers held at the VLR (MSC). The MSRN is then used to route the call to the MSC which controls the base station in the MSs current location. The database in the VLR can be accessed by the IMSI, the TMSI or the MSRN. Typically there will be one VLR per MSC.  Equipment Identity Register (EIR) The EIR contains a centralized database for validating the International Mobile Equipment Identity (IMEI).This database is concerned solely with MS equipment and not with the subscriber who is using it to make or receive a call. The EIR database consists of lists of IMEIs (or ranges of IMEIs) organized as follows: White List Contains those IMEIs which are known to have been assigned to valid MS equipment.  Black List Contains IMEIs of MS which have been reported stolen or which are to be denied service for some other reason.  Grey List Contains IMEIs of MS which have problems (for example, faulty software). These are not, however, sufficiently significant to warrant a ‘‘black listing”. The EIR database is remotely accessed by the MSCs in the network and can also be accessed by an MSC in a different PLMN. As in the case of the HLR, a network may well contain more than one EIR with each EIR controlling certain blocks of IMEI numbers. The MSC contains a translation facility, which when given an IMEI, returns the address of the EIR controlling the appropriate section of the equipment database.  Authentication Centre (AUC) The AUC is a processor system, it performs the “authentication” function.

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It will normally be co-located with the Home Location Register (HLR) as it will be required to continuously access and update, as necessary, the system subscriber records. The AUC/HLR centre can be co-located with the MSC or located remote from the MSC. The authentication process will usually take place each time the subscriber “initializes” on the system.

Fig 3.8: Showing IMEI hierarchy

 Authentication Process To discuss the authentication process we will assume that the VLR has all the information required to perform that authentication process (Kc, SRES and RAND). If this information is unavailable, then the VLR would request it from the HLR/AUC. 1. Triples (Kc, SRES and RAND) are stored at the VLR. 2. The VLR sends RAND via the MSC and BSS, to the MS (unencrypted).

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3. The MS, using the A3 and A8 algorithms and the parameter Ki stored on the MS SIM card, together with the received RAND from the VLR, calculates the values of SRES and Kc. 4. The MS sends SRES unencrypted to the VLR 5. Within the VLR the value of SRES is compared with the SRES received from the mobile. If the two values match, then the authentication is successful. 6. If cyphering is to be used, Kc from the assigned triple is passed to the BTS. 7. The mobile calculates Kc from the RAND and A8 and Ki on the SIM. 8. Using Kc, A5 and the GSM hyperframe number, encryption between the MS and the BSS can now occur over the air interface . Triples generation The triples are generated at the AUC by: RAND = Randomly generated number. SRES = Derived from A3 (RAND, Ki). Kc = Derived from A8 (RAND, Ki). A3 = From 1 of 16 possible algorithms defined on allocation of IMSI and creation of SIM card. A8 = From 1 of 16 possible algorithms defined on allocation of IMSI and creation of SIM card. Ki = Authentication key, assigned at random together with the versions of A3 and A8. The first time a subscriber attempts to make a call, the full authentication process takes place. However, for subsequent calls attempted within a given system control time period, or within a single system provider’s network, authentication may not be necessary, as the data generated during the first authentication will still be available.  Interworking Function (IWF) The IWF provides the function to enable the GSM system to interface with the various forms of public and private data networks currently available. The basic features of the IWF are listed below.
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 Data rate adoption.  Protocol conversion. Some systems require more IWF capability than others, this depends upon the network to which it is being connected. The IWF also incorporates a ‘‘modem bank”, which may be used when, for example, the GSM Data Terminal Equipment (DTE) exchanges data with a land DTE connected via an analogue modem.

Fig 3.9: Authentication Process  Echo Canceller (EC)
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An EC is used on the PSTN side of the MSC for all voice circuits. Echo control is required at the switch because the inherent GSM system delay can cause an unacceptable echo condition, even on short distance PSTN circuit connections. The total round trip delay introduced by the GSM system (the cumulative delay caused by call processing, speech encoding and decoding etc) is approximately 180 mS. This would not be apparent to the MS subscriber, but for the inclusion of a 2-wire to 4-wire hybrid transformer in the circuit. This is required at the land party’s local switch because the standard telephone connection is 2-wire. The transformer causes the echo. This does not affect the land subscriber. During a normal PSTN land to land call, no echo is apparent because the delay is too short and the user is unable to distinguish between the echo and the normal telephone “side tone”. However, without the EC and with the GSM round trip delay added, the effect would be very irritating to the MS subscriber, disrupting speech and concentration. The standard EC will provide cancellation of up to 68 milliseconds on the “tail circuit” (the tail circuit is the connection between the output of the EC and the land telephone)

3.5 - OPERATIONS AND MAINTENANCE SYSTEM
The operations and maintenance system provides the capability to manage the GSM network remotely. This area of the GSM network is not currently tightly specified by the GSM specifications, it is left to the network provider to decide what capabilities they wish it to have. The Operations and Maintenance System comprises of two parts  Network Management Centre (NMC) The Network Management Centre (NMC) has a view of the entire PLMN and is responsible for the management of the network as a whole. The NMC resides at the
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top of the hierarchy and provides global network management. The NMC offers the ability to provide hierarchical regionalized network management of a complete GSM system.It is responsible for operations and maintenance at the network level, supported by the OMCs which are responsible for regional network management. The NMC is therefore a single logical facility at the top of the network management hierarchy. The NMC has a high level view of the network, as a series of network nodes and interconnecting communications facilities. The OMC, on the other hand, is used to filter information from the network equipment for forwarding to the NMC, thus allowing it to focus on issues requiring national co-ordination. The NMC can also co-ordinate issues regarding interconnection to other networks, for example the PSTN. The NMC can take regional responsibility when an OMC is not manned, with the OMC acting as a transit point between the NMC and the network equipment. The NMC provides operators with functions equivalent to those available at the OMC.

FUNCTIONALITY OF NMC  Monitors nodes on network  Monitors GSM network element statistics  Enables long term planning for the entire network  Monitors OMC regions and provides information to OMC staff  Passes on statistical information from one OMC region to another to improve problem solving strategies

Fig 3.10: Showing NMC and OMC nodes

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 Operations and Maintenance Centre (OMC) The Operations and Maintenance Centre (OMC) is a centralized facility that supports the day to day management of a cellular network as well as providing a database for long term network engineering and planning tools. An OMC manages a certain area of the PLMN thus giving regionalized network management. The OMC provides a central point from which to control and monitor the other network entities (i.e. base stations, switches, database, etc) as well as monitor the quality of service being provided by the network. At present, equipment manufacturers have their own OMCs which are not compatible in every aspect with those of other manufacturers. This is particularly the case between radio base station equipment suppliers, where in some cases the OMC is a separate item and Digital Switching equipment suppliers, where the OMC is an integral, but functionally separate, part of the hardware. There are two types of OMC these are  OMC (R) OMC controls specifically the Base Station System.  OMC (S) OMC controls specifically the Network Switching System. The OMC should support the following functions as per ITS–TS

recommendations:  Event/Alarm Management.  Fault Management.  Performance Management.  Configuration Management.  Security Management.

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 OMC VS NMC

3.6 - THE NETWORK IN REALITY In reality a GSM network is much more complicated than we have seen. The diagram opposite illustrates how multiple BSS and Network Switching System components will be connected within a network. A typical city will have approximately the following number of network components

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Fig 3.11: Network in reality

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CHAPTER NO.4 INTRODUCTION TO MICROCONTROLLER

Important points: • What is a microcontroller? • PIC Microcontroller • Pin Configuration
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• Special Microcontroller Features
4.1 - WHAT IS A MICROCONTROLLER? There are various definitions of microcontroller available. Some of them are as follows: • A highly integrated chip that contains all the components comprising a controller. Typically, this includes a CPU, RAM, some form of ROM, I/O ports, and timers. Unlike a general-purpose computer, which also includes all of these components, a microcontroller is designed for a very specific task – to control a particular system. As a result, the parts can be simplified and reduced, which cuts down on production costs. • A highly integrated microprocessor designed specifically for use in embedded systems. Microcontrollers typically include an integrated CPU, memory (a small amount of RAM, ROM, or both), and other peripherals on the same chip. • A microcontroller is a computer-on-a-chip optimized to control electronic devices. It is a type of microprocessor emphasizing self-sufficiency and costeffectiveness, in contrast to a general-purpose microprocessor, the kind used in a PC. A typical microcontroller contains all the memory and I/O interfaces needed, whereas a general purpose microprocessor requires additional chips to provide these necessary functions. A microcontroller is a single integrated circuit, commonly with the following features: • • Central processing unit - ranging from small and simple 4-bit processors to sophisticated 32- or 64-bit processors Input/output interfaces such as serial ports (UARTs)
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• • • • • •

Other serial communications interfaces like I²C, Serial Peripheral Interface and Controller Area Network for system interconnect Peripherals such as timers and watchdog RAM for data storage ROM, EPROM, EEPROM or Flash memory for program storage Clock generator - often an oscillator for a quartz timing crystal, resonator or RC circuit Many include analog-to-digital converters

This integration drastically reduces the number of chips and the amount of wiring and PCB space that would be needed to produce equivalent systems using separate chips and have proved to be highly popular in embedded systems since their introduction in the 1970s. Some microcontrollers can afford to use Harvard architecture: separate memory buses for instructions and data, allowing accesses to take place concurrently. Microcontrollers take the largest share of sales in the wider microprocessor market. Over 50% are "simple" controllers, and another 20% are more specialized digital signal processors (DSPs). A typical home in a developed country is likely to have only one or two general-purpose microprocessors but somewhere between one and two dozen microcontrollers. A typical mid range automobile has as many as 50 or more microcontrollers. They can also be found in almost every electrical device: washing machines, microwave ovens, telephones etc.

Fig 4.1: A PIC 18F8720 microcontroller in an 80-pin TQFP package. Manufacturers have often produced special versions of their microcontrollers in order to help the hardware and software development of the target system. These have included EPROM versions that have a "window" on the top of the device
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through which program memory can be erased by ultra violet light, ready for reprogramming after a programming ("burn") and test cycle. Other versions may be available where the ROM is accessed as an external device rather than as internal memory. A simple EPROM programmer, rather than a more complex and expensive microcontroller programmer, may then be used, however there is a potential loss of functionality through pin outs being tied up with external memory addressing rather than for general input/output. These kind of devices usually carry a cost up in part prices but if the target production quantities are small, certainly in the case of a hobbyist, they can be the most economical option compared with the set up charges involved in mask programmed devices. A more rarely encountered development microcontroller is the "piggy back" version. This device has no internal ROM memory; instead pin outs on the top of the microcontroller form a socket into which a standard EPROM program memory device may be installed. The benefit of this approach is the release of microcontroller pins for input and output use rather than program memory. These kinds of devices are normally expensive and are impractical for anything but the development phase of a project. Originally, microcontrollers were only programmed in assembly language, or later in C code. Recent microcontrollers integrated with on-chip debug circuitry accessed by In-circuit emulator via JTAG, which enables a programmer to debug the software of an embedded system with a debugger. Some microcontrollers have begun to include a built-in high-level programming language interpreter for greater ease of use. The Intel 8052 and Zilog Z8 were available with BASIC very early on, and BASIC is more recently used in the popular BASIC Stamp MCUs. Some microcontrollers such as Analog Device's Blackfin processors can be programmed using LabVIEW, which is a high level programming language. For almost every manufacturer of bare microcontrollers, there are a dozen little companies repacking its products into more hobbyist-friendly packages. Their product is often an MCU preloaded with a BASIC or similar interpreter, soldered onto a Dual Inline Pin board along with a power regulator. PIC micros seem to be very popular, possibly due to good static protection. More powerful examples (e.g. faster execution, more RAM and code space) seem to be based on Atmel AVR or Hitachi chips and now ARM.

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4.1.1 - Arduino
Arduino is an open-source physical computing platform based on a simple input/output board and a development environment that implements the Processing/Wiring language. Arduino can be used to develop stand-alone interactive objects or can be connected to software on your computer (e.g. Flash, Processing, MaxMSP). The boards can be assembled by hand or purchased preassembled; the open-source IDE can be downloaded for free. Arduino uses an ATmega8 or ATmega168 microcontroller from Atmel's Atmel AVR series.

4.1.2 - Platforms from Parallax, Inc
BASIC Stamp by Parallax, is the 'big name' in BASIC microcontrollers. They are Microchip PIC micros programmed with an interpreter that processes the program stored in an external EEPROM. Several different modules are available of varying processing speeds, RAM, and EEPROM sizes. Most popular is the original BASIC Stamp 2 module. The BASIC Stamp is used by Parallax as a platform for introductory programming and robotic kits. SX-Key, Parallax's development tool for the SX line of microcontrollers, supporting every SX chip commercially available. Using free SX-Key software (Assembly language), or the SX/B Compiler (BASIC-style language) from Parallax, the SX-Key programming tool can program SX chips in-system and perform in-circuit sourcelevel debugging. Propeller, A multi-core microcontroller developed by Parallax, Inc, features eight 32bit cores and 32 I/O pins in the currently released version. Each core operates independently at 80Mhz, it is programmed in a language named SPIN(tm) which was developed by Parallax to support this unique micro.

4.1.3 - Picaxe
This PICAXE range of controllers from Revolution Education Limited is based upon Microchip PICmicro's programmed with a BASIC interpreter. Using internal EEPROM or Flash to store the user's program they deliver a single-chip solution and are quite inexpensive. A PICAXE programmer is simply a serial plug plus two resistors. Complete development software, comprehensive documentation and application notes are all available free of charge.
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The BASIC-like programming language is almost identical to that used by Parallax's Basic Stamp 1 (BS1) but has been enhanced to support on-chip hardware and additional functionality. In common with the BS1 programming language, the PICAXE has support only for a limited number of variables, but allows access to internal RAM for storage which helps overcome that limitation. The 5.0.X versions of the Visual IDE (the Programming Editor) introduced 'enhanced compilers' which support block-structured programming constructs plus conditional compilation and other directives. Initially targeted at the UK educational sector, use of the PICAXE has spread to hobbyists, semi-professionals and it can also be found inside commercial products. With its user base in many countries, the PICAXE has steadily gained a good international reputation.

4.1.4 - ZX-24, ZX-40, ZX-44
The ZX series MCUs are based on the Atmel ATmega32 and ATmega644 processors. The devices run a field-upgradeable Virtual Machine that features built-in multitasking, 32-bit floating point math and 1.5K to 3.5K of RAM for user's programs. Multi-tasking facilitates a more structured approach to coding for interface devices that require prompt service, e.g. serial devices, infrared remotes, etc. The programming language for the ZX series is ZBasic, a modern dialect of Basic modeled after Microsoft's Visual Basic. The biggest improvement over the typical MCU Basic dialect is the availability of parameterized subroutines/functions that support local variables. Strong type checking is another improvement that aids in writing correct programs more quickly. User-defined types (structures) are also supported along with aliases, based variables, sub-byte data types (Bit and Nibble) and other advanced capabilities.

4.2 - PIC MICROCONTROLLER
PIC is a family of Harvard architecture microcontrollers made by Microchip Technology, derived from the PIC1650 originally developed by General Instrument's Microelectronics Division. PICs are popular with developers and hobbyists alike due to their low cost, wide availability, large user base, extensive collection of application notes, availability of

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low cost or free development tools, and serial programming (and re-programming with flash memory) capability.

4.2.1 - Core Architecture of the 8-bit CPUs
The PIC architecture is distinctively minimalist. It is characterized by the following features: • • • • • • • • • Separate code and data spaces (Harvard architecture) A small number of fixed length instructions Most instructions are single cycle execution (4 clock cycles), with single delay cycles upon branches and skips A single accumulator (W), the use of which (as source operand) is implied (ie is not encoded in the opcode) All RAM locations function as registers as both source and/or destination of math and other functions. A hardware stack for storing return addresses A fairly small amount of addressable data space (typically 256 bytes), extended through banking Data space mapped CPU, port, and peripheral registers The program counter is also mapped into the data space and writable (this is used to synthesize indirect jumps) Unlike most other CPUs, there is no distinction between "memory" and "register" space because the RAM serves the job of both memory and registers, and the RAM is usually just referred to as the register file or simply as the registers.

4.2.2 - Data Space (RAM)
PICs have a set of register files that function as general purpose ram, special purpose control registers for on-chip hardware resources are also mapped into the data space. The addressability of memory varies depending on device series, and all PIC devices have some banking mechanism to extend the addressing to additional memory. Later series of devices feature move instructions which can cover the whole addressable space, independent of the selected bank. In earlier devices (ie. the baseline and midrange cores), any register move had to be through the accumulator.
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To synthesize indirect addressing, a "file select register" (FSR) and "indirect register" (INDF) are used: A read or write to INDF will be to the memory pointed to by FSR. Later devices extended this concept with post and pre increment/decrement for greater efficiency in accessing sequentially stored data. This also allows FSR to be treated like a stack pointer. External data memory is not directly addressable except in some high pin count PIC18 devices.

4.2.3 - Code Space
All PICs feature Harvard architecture, so the code space and the data space are separate. PIC code space is generally implemented as EPROM, ROM, or FLASH ROM. In general, external code memory is not directly addressable due to the lack of an external memory interface. The exceptions are PIC17 and select high pin count PIC18 devices.

4.2.4 - Word Size
The word size of PICs can be a source of confusion. All PICs (except dsPICs and PIC24s) handle data in 8-bit chunks, so they should be called 8-bit microcontrollers. However, the unit of addressability of the code space is not generally the same as the data space. For example, PICs in the baseline and mid-range families have program memory addressable in the same wordsize as the instruction width, ie. 12 or 14 bits respectively. In contrast, in the PIC18 series, the program memory is addressed in 8bit (bytes), which differs from the instruction width of 16 bits. In order to be clear, the program memory capacity is usually stated in number of (single word) instructions, rather than in bytes.

4.2.5 - Stacks
PICs have a hardware call stack, which is used to save return addresses. The hardware stack is not software accessible on earlier devices, but this changed with the 18 series devices.

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Hardware support for a general purpose parameter stack was lacking in early series, but this greatly improved in the 18 series, making the 18 series architecture more friendly to high level language compilers.

4.2.6 - Instruction Set
PICs instructions vary in number from about 35 instructions for the low-end PICs to about 70 instructions for the high-end PICs. The instruction set includes instructions to perform a variety of operations on registers directly, the accumulator and a literal constant or the accumulator and a register, as well as for conditional execution, and program branching. Some operations, such as bit setting and testing, can be performed on any register, but bi-operand arithmetic operations always involve W -- writing the result back to either W or the other operand register. To load a constant, it is necessary to load it into W before it can be moved into another register. On the older cores, all register moves needed to pass through W, but this changed on the "high end" cores. PIC cores have skip instructions which are used for conditional execution and branching. The skip instructions are: 'skip if bit set', and, 'skip if bit not set'. Because cores before PIC18 had only unconditional branch instructions, conditional jumps are synthesized by a conditional skip (with the opposite condition) followed by a branch. Skips are also of utility for conditional execution of any immediate single following instruction. The PIC architecture has no (or very meager) hardware support for saving processor state when servicing interrupts. The 18 series improved this situation by implementing shadow registers which save several important registers during an interrupt.

4.3 - HIGH-PERFORMANCE RISC CPU
• • • • • •

Lead-free; RoHS-compliant Operating speed: 20 MHz, 200 ns instruction cycle Operating voltage: 4.0-5.5V Industrial temperature range (-40° to +85°C) 15 Interrupt Sources 35 single-word instructions
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•

All single-cycle instructions except for program branches (two-cycle)

Fig 4.2: Pin Configuration of PIC 16F877A

4.4 - FEATURES: 4.4.1 - Special Microcontroller Features
• • • • • • • • • •

Flash Memory: 14.3 Kbytes (8192 words) Data SRAM: 368 bytes Data EEPROM: 256 bytes Self-reprogrammable under software control In-Circuit Serial Programming via two pins (5V) Watchdog Timer with on-chip RC oscillator Programmable code protection Power-saving Sleep mode Selectable oscillator options In-Circuit Debug via two pins
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4.4.2 - Peripheral Features
• • •

33 I/O pins; 5 I/O ports Timer0: 8-bit timer/counter with 8-bit prescaler Timer1: 16-bit timer/counter with prescaler
o

Can be incremented during Sleep via external crystal/clock

•

Timer2: 8-bit timer/counter with 8-bit period register, prescaler and postscaler Two Capture, Compare, PWM modules
o o o

•

16-bit Capture input; max resolution 12.5 ns 16-bit Compare; max resolution 200 ns 10-bit PWM SPI Master I2C Master and Slave

•

Synchronous Serial Port with two modes:
o o

• •

USART/SCI with 9-bit address detection Parallel Slave Port (PSP)
o

8 bits wide with external RD, WR and CS controls

•

Brown-out detection circuitry for Brown-Out Reset

4.4.3 - Analog Features
• • •

10-bit, 8-channel A/D Converter Brown-Out Reset Analog Comparator module
o o o

2 analog comparators Programmable on-chip voltage reference module Programmable input multiplexing from device inputs and internal VREF Comparator outputs are externally accessible.

o

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CHAPTER NO.5 SOFTWARE TOOLS

Important Points: • Visual Basic • Microsoft Office Access • Crystal Report
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In order to achieve the goals we use many types of software. For PIC microcontroller we used MPLAB and the complier was “picclite”. Bill Calculation software is used for creating electricity bill for consumer; Data is collected through automated meter reading after every 2 minutes. The programming tools which are used for creating this software is Visual Basic and Microsoft Access. Visual Basic is not only allowing programmer to create simple GUI (Graphical User Interface) application, but can also develop fairly complex application as well.

5.1 – VISUAL BASIC:
Programming in Visual Basic is a combination of visually arranging components or control on a form, specifying attributes and actions of those components and writing additional line of code for more functionality. Visual Basic (VB) is an event driven programming language and associated development environment from Microsoft for its COM programming model. Visual Basic was derived from BASIC and enables the rapid application development (RAD) of graphical user interface (GUI) applications, access to databases using DAO, RDO, or ADO, and creation of ActiveX controls and objects. Scripting languages such as VBA and VB Script are syntactically similar to Visual Basic, but perform differently.

Fig 5.1: Microsoft VB
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A programmer can put together an application using the components provided with Visual Basic itself. Programs written in Visual Basic can also use the Windows API, but doing so requires external function declarations.

5.1.1 - Language Features
Visual Basic was designed to be easy to learn and use. The language not only allows programmers to create simple GUI applications, but can also develop fairly complex applications as well. Programming in VB is a combination of visually arranging components or controls on a form, specifying attributes and actions of those components, and writing additional lines of code for more functionality. Since default attributes and actions are defined for the components, a simple program can be created without the programmer having to write many lines of code. Performance problems were experienced by earlier versions, but with faster computers and native code compilation this has become less of an issue. Although programs can be compiled into native code executables from version 5 onwards, they still require the presence of runtime libraries of approximately 2 MB in size. This runtime is included by default in Windows 2000 and later, but for earlier versions of Windows it must be distributed together with the executable. Forms are created using drag and drop techniques. A tool is used to place controls (e.g., text boxes, buttons, etc.) on the form (window). Controls have attributes and event handlers associated with them. Default values are provided when the control is created, but may be changed by the programmer. Many attribute values can be modified during run time based on user actions or changes in the environment, providing a dynamic application. For example, code can be inserted into the form resize event handler to reposition a control so that it remains centered on the form, expands to fill up the form, etc. By inserting code into the event handler for a key press in a text box, the program can automatically translate the case of the text being entered, or even prevent certain characters from being inserted. Visual Basic can create executables (EXE files), ActiveX controls, DLL files, but is primarily used to develop Windows applications and to interface web database systems. Dialog boxes with less functionality (e.g., no maximize/minimize control) can be used to provide pop-up capabilities. Controls provide the basic functionality of the application, while programmers can insert additional logic within the appropriate
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event handlers. For example, a drop-down combination box will automatically display its list and allow the user to select any element. An event handler is called when an item is selected, which can then execute additional code created by the programmer to perform some action based on which element was selected, such as populating a related list.

5.2 - MICROSOFT OFFICE ACCESS
Bill calculation software used Microsoft access for storing data. Microsoft Access is a relational management system for Microsoft which contributes the relational Microsoft jet database engine with a graphical user interface (GUI) and software development tools.

Fig 5.2: Microsoft Office Access

5.2.1 – Features
One of the benefits of Access from a programmer's perspective is its relative compatibility with SQL (structured query language) —queries may be viewed and edited as SQL statements, and SQL statements can be used directly in Macros and VBA Modules to manipulate Access tables. In this case, "relatively compatible" means that SQL for Access contains many quirks, and as a result, it has been dubbed "Bill's SQL" by industry insiders. Users may mix and use both VBA and "Macros" for programming forms and logic and offers object-oriented possibilities. MSDE (Microsoft SQL Server Desktop Engine) 2000, a mini-version of MS SQL Server 2000, is included with the developer edition of Office XP and may be used with Access as an alternative to the Jet Database Engine.
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5.2.2 – Uses
Access is used by small businesses, within departments of large corporations, and hobby programmers to create ad hoc customized desktop systems for handling the creation and manipulation of data. Access can be used as a database for basic web based applications hosted on Microsoft's Internet Information Services and utilizing Microsoft Active Server Pages ASP. Some professional application developers use Access for rapid application development, especially for the creation of prototypes and standalone applications that serve as tools for on-the-road salesmen. Access does not scale well if data access is via a network, so applications that are used by more than a handful of people tend to rely on Client-Server based solutions. However, an Access "front end" (the forms, reports, queries and VB code) can be used against a host of database back ends, including JET (file-based database engine, used in Access by default), Microsoft SQL Server, Oracle, and any other ODBCcompliant product.

5.3 - CRYSTAL REPORT
Crystal Reports is a business intelligence application used to design and generate reports from a wide range of data sources. Several other applications, such as Microsoft Visual Studio, bundle an OEM version of Crystal Reports as a general purpose reporting tool. Crystal Reports became the defacto report writer when Microsoft released it with Visual Basic.

5.3.1 - Creating reports
Users install Crystal Reports on a computer and use it to select specific rows and columns from a table of compatible data (see "Supported data sources" below). Users can then arrange the data on the report in the format needed. Once the report layout is complete it is saved as a file with the extension RPT. A report can be rerun anytime by reopening the RPT file and 'refreshing' the data. If the source data has been updated then the refreshed report will reflect those updates. The report can then be previewed on the screen, printed onto paper or exported to one of several different file formats such as PDF, Excel, text or CSV.

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Report formats can vary from a simple column of values to layouts featuring pie charts, bar charts, cross-tab summary tables and nested sub reports. Crystal Reports is designed for "presentation quality" reports so there are many options for enhanced formatting.

5.3.2 - Running reports locally
The users who design the reports can run them as needed from within the report designer. When running reports directly within the report designer the user has the ability to change any feature of the report. The user can also create variations of the report by saving the modified RPT file under another name. It is also possible to run a Crystal Report without using the full Crystal Reports designer software. These alternate methods for running reports include locally installed viewers, schedulers, and report distribution tools. These are typically thirdparty software programs (independent of Business Objects) that allow you to open, refresh, preview, print and export an RPT file. In 2007 Business Objects released their own viewer, Crystal Reports Viewer XI, but unlike the independent viewers it does not allow the user to refresh the report, only to view static data saved in the RPT file. Some of the independent viewers add other capabilities such as allowing the user to schedule a report to run automatically at certain times. Still others allow reports to be burst and /or distributed via Email. Crystal report is bundled with a set of ActiveX controls that, when embedded in a simple GUI, can provide an alternative user interface. These same controls allow reports to be deconstructed into their base objects. This, in turn, allows the same reports to be generated at run time, customizing them as necessary. Bill Calculation software used simple tools for developing this software.

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CHAPTER NO.6 HARDWARE DETAILS

Important points: • Energy Meter • Optocoupler • Power Supply
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• LCD
6.0 - HARDWARE DETAILS
Implementation of the project was the most crucial and hectic phase of the project. Day to day problems in the hardware circuitry adds fun to the game. In order to implement the project following components are used: • • • • • • • • • • • Meter Microcontroller (PIC) Opto coupler Power supply Transformer LC circuit LM 311 (Voltage Regulator) Bridge Rectifier LCD Serial Port Mobile

Some of the components have been discussed in detail in previous chapters; the functionality of the rest is as follows:

6.1 - ANALOG ENERGY METER 6.1.1 - Overview:
An electric meter or an energy meter is a device that measures the amount of electricity consumed by a residence or business. The most common units of measurements for electricity in Pakistan are kilo watt-hour. Therefore kilowatt-hour meters are widely used in Pakistan by WAPDA. Utilities record the values read by these meters to generate invoice for consumers. Although energy meters are of various types and display reading in analog as well as in digital fashion, but WAPDA uses analog electromechanical induction meters.

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6.1.2 - Electromechanical Meters:
Electromechanical induction meters are widely used in Pakistan due to their low price and good reading accuracy and long life. Their price range is form Rs2000 to Rs3000. WAPDA uses meters made by PEL (PAK ELEKTRON). The prototype is MC 8 single phase and TBL three phase meter. All these meters are under license of ABBUSA.

MC8 Single Phase Meter Parameters Voltage Current (Nominal) Current (Maximum) Values 220-240V 10, 20, 40A 40, 60, 80, 100A

TBL Poly-Phase Meter Parameters Voltage Current (Nominal) Current (Maximum) Values 3x200/400V 15A 90A

6.1.3 - Technology:
The electromechanical induction meter operates by counting the revolutions of an aluminum disc which is made to rotate at a speed proportional to the power. The number of revolutions is thus proportional to the energy usage. The rotating disc in this type of meter is, in fact, an electric motor of a type called a reluctance motor or eddy current motor. It consumes a small amount of power, typically around 2 watts. The metallic disc is acted upon by two coils. One coil is connected in such a way that it produces a magnetic flux in proportion to the voltage and the other produces a magnetic flux in proportion to the current. This produces eddy currents in the disc and the effect is such that a force is exerted on the disc in proportion to the product of the instantaneous current and voltage. A permanent magnet exerts an opposing force proportional to the speed of rotation of the disc - this act as a brake which
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causes the disc to stop spinning when power is drawn rather than allowing it to spin faster and faster. This causes the disc to rotate at a speed proportional to the power being used. The type of meter described above is used on a single-phase AC supply. Different phase configurations use additional voltage and current coils.

Fig 6.1: A typical energy meter

6.1.4 - Working:
The aluminum disc is supported by a spindle which has a worm gear which drives the register. The register is a series of dials which record the amount of power used. The dials may be of the cyclometer type where for each dial a single digit is shown through a window in the face of the meter, or of the pointer type where a pointer indicates each digit. It should be noted that with the dial pointer type, adjacent pointers generally rotate in opposite directions due to the gearing mechanism. The amount of energy represented by one revolution of the disc is denoted by the symbol KWH which is given in units of watt-hours per revolution. The value 7.2 is commonly seen. Using the value of KWH, one can determine their power consumption at any given time by timing the disc with a stopwatch. If the time in seconds taken by the disc to complete one revolution is t, then the power in watts is P
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= 3600×Kh/t. For example, if KWH = 7.2, as above, and one revolution took place in 14.4 seconds, the power is 1800 watts. This method can be used to determine the power consumption of household devices by switching them on one by one. Most domestic electricity meters must be read manually, whether by a representative of the power company or by the customer. In Pakistan the meter reading is mostly done by the representatives of Electric Supply Company. They take the meter readings on monthly basis.

6.1.5 - Accuracy:
In an induction type meter, creep is a phenomenon that can adversely affect accuracy that occur when the meter disc rotates continuously with potential applied and the load terminals open circuited. All the meters are first tested in WAPDA lab before installation to the customer’s residence or business. In testing they check the disc rotational speed. If it is not according to the company standard, it is adjusted.

6.2 - OPTO COUPLER / OPTO ISOLATOR:
Opto coupler is basically used to transmit a signal from one end to the other by the use of a short optical transmission path. In our particular case an LED (photo diode) and a detector serves the purpose. The light from the LED is blocked until the hole on the aluminum disc comes in direct contact with LED; at this stage light from the LED is allowed to pass through the hole and thus reaches the detector (transistor), which on receiving the light pass an interrupt to the IC connected directly to it. In this way the revolutions of the aluminum disc are counted and a digital reading mechanism is established.

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Fig 6.2: Opto coupler pin configuration

6.3 - POWER SUPPLY:
Power supply is used to operate the electronics components used in the circuitry. Since such components cannot be directly connected to 220 volts, therefore the role of the power supply comes into contact. The supply in this case is specially designed for the particular circuitry to provide a voltage equal to 5 V, in order to operate IC and other related components. The power supply is fitted with a step down transformer which takes the voltage from power line prior to entering the meter, and then it lowers the voltage to the desired value. The hierarchy of the complete power supply goes as follows:

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Voltage Source
6.4 - LC CIRCUIT:

Transformer

A specially designed LC circuit is placed right after the power supply block in order to remove unwanted signal from the Rectifier block that is, at deregulation of power supply voltage there are some ripples and additive noise that comes into action and may disrupt the whole function of the LC Circuit circuit is used to overcome such circuit. This LC difficulties and thus provide a noise free signal at the other end.

Regulator The capacitors used in this LC circuit play a vital role in the removal of ripples made
by the transformer and/or any other factor.

Capacitor
6.5 - VOLTAGE REGULATOR (LM 311):

Load Voltage regulator is used in order to prevent the IC from exposure to high voltage
typically in the range of 10-20V.Voltage regulator operates at a certain range and has the capability of providing a fixed voltage at on end no matter whatever the voltage occurs at the other end; provided that it is in the range of specifications. The voltage regulator (LM 311) used in our case has the following specifications: voltage regulators’

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• • • • •

Operates from single 5V supply Input current: 150 nA max. over temperature Offset current: 20 nA max. over temperature Differential input voltage range: ±30V Power consumption: 135 mW at ±15

Following is its parametric Table: • • • • • Response Time 0.1 us Offset Voltage max, 25C 7.5 mV Output Bus Open Drain Supply Min 5 Volt Supply Max 36 Volt

6.6 - LCD:
LCD is used to display the current (updated) and the previous reading of the meter; it is updated at every increment of the unit. LCD is directly connected to the PIC micro controller from a where a stream of numbers is flushed into the LCD to display the readings of the meter.

CHAPTER NO.7 FUTURE ADVANCEMENTS IN PROJECT
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Important Points • • • • • Duplex Communication Power Shut Down Data Storage Composite/Multi phases meter Networking

7.0 - FUTURE ADVANCEMENTS IN PROJECT
Luckily, we have achieved the goals of the project. During the project, we faced a lot of problems while achieving the goals and it was really a very tough job to do so. However due to wide scope in this domain a lot of advancements can be made in this project. Due to time constraints and the hardware problems, we were unable to work for advancement part but we recommend our juniors to work on it. Following are the some proposed advancements in my project. • • • • • Duplex Communication Power Shut Down Data Storage Composite/Multi phases meter Networking

7.1 - DUPLEX COMMUNICATION:
The original project is based on the one way or single communication system which handicap and close optional direction of server side. The idea of improvisation of the communication system inherited for making the project system more efficient. There
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can be duplex communication instead of simplex communication. A simplex circuit is one where all signals can flow in only one direction at a time. Examples are as follows: • • • Television broadcast Commercial radio broadcast (not Citizens' band radio , etc.) Internet multicast

A duplex communication system is a system composed of two connected parties or devices which can communicate with one another in both directions. The SMS can be sending when it is requested by the server end. It can be half duplex or full duplex. A half-duplex system provides for communication in both directions, but only one direction at a time (not simultaneously) Example of a half-duplex system is walkietalkie style.

Fig 7.1: A simple illustration of a half-duplex communication system. A full-duplex system allows communication in both directions, and unlike halfduplex, allows this to happen simultaneously Examples: Telephone, Mobile Phone, etc.

Fig 7.2: A simple illustration of a full-duplex communication system

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It can save the memory and server can get information when required. The problem with me for using duplex communication is I don’t have registered version of compiler so I m unable to do duplex communication.

7.2 - POWER SHUT DOWN:
After improving the communication system to two way the path for the advancement of the project opens. The option for shut down of power supply can be exercised by devising and placing the relays with incoming power circuit of energy meter which may operate after receiving the directional signal from server end.

Fig 7.3: Showing meter dail The multiple objectives can be achieved after the improvisation of the system in energy meter besides the main objective of automated meter. a) Power supply can be disconnected when required an occasion of default of payment of electricity bill or any other reason. b) A sensory devise can be installed at meter reading index or sensitive area from where the functioning of meter can be effected/stopped by anyone for unlaw purpose. This sensory devise, or touch the sensitive area may pass signal to relay to auto shut down the power supply. It will bring big change for effective control of power theft and power supply of stealer can automatically be shut down through system. c) The unauthorized extension of load and its usage can be control through fixing maximum load bearing capacity by sensory gadget. The power supply can be shut down by tripping the gadget after fixed load as the load beyond appeared load exceed, the relay operates to shut the power supply.
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7.3 - DATA STORAGE
The various data regarding electrical elements can be stored in the in controller in meter for example • • • • Meter reading based upon data or timing. Load put on the system. Voltage. Power tripping record.

Fig 7.4: Showing reading in KWH

7.4 - COMPOSITE/MULTI PHASE METER:
The option for manufacturing the composite/multi phase meter cannot be rejected. We may concentrate and put consideration for making a panel meter which may have only one input which feed power at bus bar circuit provided on meter and from where supply can be provided to various output which contain its own meter reading register. There could be facility of replacing one sub meter in a case of fault.

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Fig 7.5: Meter Panel The panel meter can provide clustering and jumping of cables and will give beautiful look. The cost of meter can be reduced.

Fig 7.6: Meter Panel

7.5 - NETWORKING:
Network can be formed with the meters which are in the panel or are vicinity of each other. An Ad-Hoc network can be formed for those meters and by using single mobile phone/GSM chip and a single microcontroller we can multiplex our data and sends the multiplexed reading the central office. So instead of attaching a dedicated mobile phone and microcontroller with every meter we can attach a single microcontroller and mobile phone with many meters. In this way project on large scale will be more cost effective.
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APPENDIX I
#include<pic.h> #include "firmlcd.h" #define PORT PORTD #define TRIS TRISD unsigned long int TEnergy = 0; unsigned long int TempTEnergy = 0; unsigned char ascii_str[16]; const unsigned char meterid[] = {"ID: 00s000"}; const unsigned char at[5] = {'a','t','e','0',13}; const unsigned char ms[23] = {'a','t','+','c','p','m','s','=','"','M','E','"',',','"','M','E','"',',','"','M','E','"',13}; const unsigned char gf[10] = {'a','t','+','c','m','g','f','=','1',13}; const unsigned char gs[22] = {'a','t','+','c','m','g','s','=','"','0','3','2','1','4','1','7','1','3','2','1','"',13}; const unsigned char gr[10] = {'a','t','+','c','m','g','r','=','1',13}; const unsigned char gd[10] = {'a','t','+','c','m','g','d','=','1',13}; /////////////////////////////////////////////////////////////////////// void Main_init(void) { ADCON0=0; ADCON1=7;
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TRISB1=0; RB1=0; TRISB2=0; RB2=0; TRISB3=0; RB3=0; } /////////////////////////////////////////////////////////////////// /*------------ Delay Function -------------*/ void delay(unsigned char x) { unsigned int i; for(i=0;i<x*200;i++){} } /////////////////////////////////////////////////////////////////// /*------------LCD Char Function----------*/ //sends one character or number to the display for setup and messages void lcd_write(const unsigned char data) { PORT = ((data/4) & 252); PORT = (PORT | 2); delay(1); PORT = (PORT & 252); PORT = ((4*data & 252) | 2); delay(1); PORT = (PORT & 252); delay(2); } void lcd_mes(const unsigned char data1) { PORT = ((data1/4 & 252) | 1); delay(1);
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PORT = (PORT | 3); delay(1); PORT = (PORT & 253); PORT = ((4*data1 & 252) | 3); delay(1); PORT = (PORT & 253); delay(2); PORT = (PORT & 252); } /////////////////////////////////////////////////////////////////// /*------------LCD Message Function--------*/ //sends a series of words to display by calling character //function and checking the line number void lcd_message (const unsigned char *ptr) { while(*ptr){ lcd_mes(*ptr++); } } /////////////////////////////////////////////////////////////////// /*------------- LCD INTEGER AND HEX FUNCTION ----------------*/ void lcd_int(unsigned long int_value) { unsigned char loop; unsigned long remainder = 0; for(loop=0;loop<11;loop++) { if(loop==1){ ascii_str[10 - loop++] = 46; } remainder = int_value % 10; ascii_str[10-loop] = remainder + 48; int_value = int_value / 10;
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//sendind string

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} for(loop=0;loop<11;loop++){ lcd_mes(ascii_str[loop]); } ascii_str[11] = 32; ascii_str[12] = 'k'; ascii_str[13] = 'W'; ascii_str[14] = 'h'; ascii_str[15] = 26; } /*------------------ LCD INITIALIZATION ------------------------ */ ///////////////////////////////////////////////////////////////////// void lcd_init(void) { ADCON0=0X00; ADCON1=0X07; TRIS =0X00; PORT =0X08; delay(180); delay(45); PORT=PORT + 2; delay(15); PORT=0X08; // // // // delay(45); PORT=PORT + 2; delay(15); PORT=0X08; //set display, Data length 4-bit, 2-line, 5x8dots //Display on, cursor off, Blinking off //Entry Mode Set, Increment Mode, Display Shift off //First initialization //First initialization // // // A2D off A2D off Data port init //initialises display to be on, clear etc //sendind string

lcd_write (0x28); lcd_write (0x0C); lcd_write (0x06); }

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void delay1(unsigned int del) { unsigned int k=0; for(;del!=0;del--){ lcd_write(goto_2_1); lcd_int(TEnergy/3); for(k=0;k<200;k++); } } void usart_init(void) { SPEN = 1; TX9 = 0; SPBRG = 64; BRGH = 1; SYNC = 0; mode) GIE=1; } void send(const unsigned char *cha, unsigned char no) { while(no!=0){ TXEN=1; TXREG = *cha++; delay1(1); while(!TRMT); TXEN=0; no--; } } unsigned int PICEEPROM_READ(unsigned int address) {
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//0 = Selects 8-bit transmission //BRGH: High Baud Rate Select bit (1 = High speed) //SYNC: USART Mode Select bit (0 = Asynchronous

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EEPGD=0; EEADR=address; RD=1; while(RD); return EEDATA; } void PICEEPROM_WRITE(unsigned int address, unsigned int data) { EEPGD=0; EEADR=address; EEDATA=data; WREN=1; EECON2=0X55; EECON2=0XAA; WR=1; while(WR); WREN=0; } void main(void) { Main_init(); usart_init(); lcd_init(); lcd_write(1); lcd_message(meterid); TEnergy = PICEEPROM_READ(0)*16777216 + PICEEPROM_READ(1)*65536 + PICEEPROM_READ(2)*256 + PICEEPROM_READ(3); lcd_write(goto_2_1); lcd_int(TEnergy/3); lcd_message(" kWh"); INTF=0; INTE=1;
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INTEDG=1; delay1(5); send(at,5); delay1(5); send(ms,23); delay1(10); send(gf,10); delay1(10); while(1){ // // lcd_write(goto_2_1); lcd_int(TEnergy/3); delay1(30); RB2 = 1; send(gd,10); lcd_write(goto_2_1); lcd_int(TEnergy/3); delay1(20); RB3 = 1; send(gs,22); delay1(1); send(ascii_str,16); RB2 = 0; delay1(20); } } static void interrupt inter (void) { if(INTF==1){ INTF = 0; RB1 = !RB1; TempTEnergy=TEnergy; PICEEPROM_WRITE(0,TempTEnergy/16777216);
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RB3 = 0;

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TempTEnergy=TempTEnergy%16777216; PICEEPROM_WRITE(1,TempTEnergy/65536); TempTEnergy=TempTEnergy%65536; PICEEPROM_WRITE(2,TempTEnergy/256); TempTEnergy=TempTEnergy%256; PICEEPROM_WRITE(3,TempTEnergy); TEnergy++; } }

Appendix II Circuit Diagram

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Appendix III

3.1 - BASIC CONCEPTS OF GSM

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3.1.1 - Frequency Spectrum
The frequency spectrum is very congested, with only narrow slots of bandwidth allocated for cellular communications. A single Absolute Radio Frequency Channel Number (ARFCN) or RF carrier is actually a pair of frequencies, one used in each direction (transmit and receive). This allows information to be passed in both directions. For each cell in a GSM network at least one ARFCN must be allocated, and more may be allocated to provide greater capacity. The RF carrier in GSM can support up to eight Time Division Multiple Access (TDMA) timeslots. That is, in theory, each RF carrier is capable of supporting up to eight simultaneous telephone calls, although this is possible, network signaling and messaging may reduce the overall number from eight timeslots per RF carrier to six or seven timeslots per RF carrier, therefore reducing the number of mobiles that can be supported. Unlike a PSTN network, where every telephone is linked to the land network by a pair of fixed wires, each MS only connects to the network over the radio interface when required. Therefore, it is possible for a single RF carrier to support many more mobile stations than its eight TDMA timeslots would lead us to believe. Using statistics, it has been found that a typical RF carrier can support up to 15, 20 or even 25 MSs. Obviously, not all of these MS subscribers could make a call at the same time, but it is also unlikely that all the MS subscribers would want to make a call at the same time. Therefore, without knowing it, MSs share the same physical resources, but at different times.

3.1.1.1 - Frequency Range
Receive(Uplink) Transmit(Downlink) Separation B\W ARFCN (MHz) GSM 900 EGSM900 890-915 880-915 (MHz) 935-960 925-960 Uplink & Downlink(MHz) 45 45 124 174

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GSM1800 PCS 1900

1710-1785 1850-1910

1805-1880 1930-1990

95 80

374 299

ARFCN= Absolute Radio Frequency Channel ARFCN Bandwidth is 200 KHz and 8 TDMA Timeslots

3.1.2 - Cell Size
The number of cells in any geographic area is determined by the number of MS subscribers who will be operating in that area, and the geographic layout of the area (hills, lakes, buildings etc).

3.1.2.1 - Large Cells
The maximum cell size for GSM is approximately 70 km in diameter, but this is dependent on the terrain the cell is covering and the power class of the MS. In GSM, the MS can be transmitting anything up to 8 Watts; obviously, the higher the power output of the MS the larger the cell size. If the cell site is on top of a hill, with no obstructions for miles, then the radio waves will travel much further than if the cell site was in the middle of a city, with many high-rise buildings blocking the path of the radio waves. Generally large cells are employed in • • • • Remote areas. Coastal regions. Areas with few subscribers. Large areas which need to be covered with the minimum number of cell sites.

3.1.2.2 - Small Cells
Small cells are used where there is a requirement to support a large number of MS’s, in a small geographic region, or where a low transmission power may be required to reduce the effects of interference. Small cells currently cover 200 m and upwards. Typical uses of small cells: • Urban areas.
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• •

Low transmission power required. High number of MSs

3.1.2.3 - The Trade Off –Large vs. Small
There is no right answer when choosing the type of cell to use. Network providers would like to use large cells to reduce installation and maintenance cost, but realize that to provide a quality service to their customers, they have to consider many factors, such as terrain, transmission power required, number of MSs etc. This inevitably leads to a mixture of both large and small cells. The cells are normally drawn as hexagonal, but in practice they are irregularly shaped, this is as a result of the influence of the surrounding terrain, or of design by the network planners.

Fig 3.1: Showing large cells geometry

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Fig 3.2: Showing large cells geometry

3.1.3 - Frequency re-use
Standard GSM has a total of 124 frequencies available for use in a network. Most network providers are unlikely to be able to use all of these frequencies and are generally allocated a small subset of the 124. For instance a network provider has been allocated 48 frequencies to provide coverage over a large area, let us take for example of England. As we have already seen, the maximum cell size is approximately 70 km in diameter, thus our 48 frequencies would not be able to cover the whole of England. To overcome this limitation the network provider must re-use the same frequencies over and over again, in what is termed a “Frequency re-use pattern”. When planning the frequency re-use pattern the network planner must take into account how often to use the same frequencies and determine how close together the cells are, otherwise co-channel and/or adjacent channel interference may occur. The network provider will also take into account the nature of the area to be covered. This may range from a densely populated city (high frequency re-use, small cells, and high capacity) to a sparsely populated rural expanse (large omni cells, low re-use, and low capacity).

 Co-channel Interference
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This occurs when RF carriers of the same frequency are transmitting in close proximity to each other, the transmission from one RF carrier interferes with the other RF carrier.  Adjacent Channel Interference This occurs when an RF source of a nearby frequency interferes with the RF carrier.

Fig 3.3: Showing frequency re-uses pattren

3.1.4 - Sectorization
The cells we have looked at up to now are called omni-directional cells. That is each site has a single cell and that cell has a single transmit antenna which radiates the radio waves to 360 degrees. The problem with employing omni-directional cells is that as the number of MS’s increases in the same geographical region, we have to increase the number of cells to meet the demand. To do this, as we have seen, we have to decrease the size of the cell and fit more cells into this geographical area. Using omni-directional cells we can only go so far before we start introducing co-channel and adjacent channel interference, both of which degrade the cellular network’s performance.

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To gain a further increase in capacity within the geographic area we can employ a technique called “Sectorization”. A sectorization split a single site into a number of cells, each cell has transmit and receive antennas and behaves as an independent cell. Each cell uses special directional antennas to ensure that the radio propagation from one cell is concentrated in a particular direction.

3.1.4.1 - Advantages of sectorization
 We are now concentrating all the energy from the cell in a smaller area 60,120,180 degrees instead of 360 degrees, we get a much stronger signal, which is beneficial in locations such as “in-building coverage”.  Secondly, we can now use the same frequencies in a much closer re-use pattern, thus allowing more cells in our geographic region which allows us to support more MSs.

3.1.4.2 - Using Sectored Sites
The distribution of RF carriers, and the size of the cells, is selected to achieve a balance between avoiding co-channel interference by geographically separating cells using the same RF frequencies, and achieving a channel density sufficient to satisfy the anticipated demand. The diagram above illustrates how, by sectoring a site we can fit more cells into the same geographical area, thus increasing the number of MS subscribers who can gain access and use the cellular network. This sectorization of sites typically occurs in
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densely populated areas, or where a high demand of MS’s is anticipated, such as conference centers/business premises.

Fig 3.4: showing different schemes of sectorization

3.1.4.3 - Site/3 Cell
A typical re-use pattern used in GSM planning is the 4 site/3 cell. For example, the network provider has 36 frequencies available, and wishes to use the 4 site/3 cell reuse pattern he may split the frequencies up as follows:

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In this configuration each cell has a total of 3 carriers and each site has a total of 9 carriers.

3.1.4.4 - 3 Site/3 Cell

As can be seen from the table, each cell now has 4 carriers and each site has 12 carriers. This has the benefit of supporting more subscribers in the same geographic region, but problems could arise with co-channel and adjacent channel interference.

3.1.5 - Switching and Control
Having established radio coverage through the use of cells, omni-directional and directional (sectored sites), now consider what happens when the MS is in motion (as MS’s tend to be). At some point the MS will have to move from one cell’s coverage area to another cell’s coverage area. Handovers from one cell to another could be for
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a number of reasons (e.g. the signal strength of the “serving cell” is less than the signal strength of a “neighbor cell”, or the MS is suffering a quality problem in the serving cell) and by handing over to one of its neighbors this may stop the quality problem. Regardless of the reason for a “handover” it has to be controlled by some entity, and in GSM that entity is the Mobile services Switching Centre (MSC). To perform a handover, the network must know which neighbor cell to hand the MS over to. To ensure that we handover to the best possible candidate the MS performs measurements of its surrounding neighbor cells and reports its findings to the network. These are then analyzed together with the measurements that the network performs and a decision is made on a regular basis as to the need for a handover. If a handover is required then the relevant signal protocols are established and the handover is controlled by the MSC. Handovers must be transparent to the MS subscriber. That is the subscriber should be unaware that a handover has occurred. Some networks may allow certain handovers to be performed at the BSS level. This would be dependent on the manufacturer’s equipment.

ACRONYMS A:
  ASP (Microsoft Active Server Pages) AMR (Automated Meter Reader)

B:
  BSS (Base Station System) BTS (Base Transceiver Station)
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D:
   DTE (Data Terminal Equipment) DSP DAO

E:
    EIR (Equipment Identity Register) EC (Echo Canceller) EPROM (Erasable p EEPROM

F:
  FSR (File Select Register) FCC (Federal Communication Commision)

G:
 GUI (Graphical User Interface)

H:
 HLR (Home Location Register)

I:
     IWF (Interworking Function) INDR (Indirect Register) ISDN (Integrated Services Digital Network) ISP (Internet Service Provider) ITU (International Telecommunication Union)

L:
 LAN(Local Area Network)

M:
    MSISDN (Mobile Station International Service Network) MS (Mobile Station) MSC (Mobile Servicing Switching Center) MSRN (Mobile Station Roaming Network)

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O:
 OMC(Operation and Maintenance Center)

P:
   PEL (Pak Electron Limited) PICs (Photonic Integrated Circuits) PWM (Pulse Width Modulation)

T:
 TRAU (Transcoder Rate Adoption Unit)

V:
 VLR (Visitor Location Register)

W:
 WAN (Wide Area Network)

References
Websites
• • • • • http://instruct1.cit.cornell.edu/courses/ee476/FinalProjects/s2005/mpd25_ yl293/476FinPrj/INDEX.HTM www.novatelwireless.com/solutions/telemetry.html http://www.active-robots.com/products/radio-solutions/radiocommunication.shtml en.wikipedia.org/wiki/GSM www.gsmworld.com
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• • • • •

www.iec.org/online/tutorials/gsm/ en.wikipedia.org/wiki/PIC_microcontroller www.microcontroller.com crystal-reports-software.com www.jaycar.com.au/images_uploaded/optocoup.pdf

Data Sheets:
• • • www.national.com/pf/LM/LM317.html www.sonyericsson.com/downloads/dg_at_2003_r4a.pdf ww1.microchip.com/downloads/en/DeviceDoc/30292c.pdf

Books
The GSM System for Mobile Communications by Michel Mouly, MarieBernadette Pautet An Introduction to GSM by Siegmund H. Redl, Matthias K. Weber, Malcolm W. Oliphant • • • • • The PIC Microcontroller - by John Morton PIC Microcontroller Project Book - by John Iovine Optoelectronics Circuits Manual - by Raymond Michael Marston Modern Digital and Analog Communication Systems by B.P. Lathi Wireless Communications by Theodore S. Rapaport

Design & Fabrication of GSM Based Electric Energy Meter