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.

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.

Design & Fabrication of GSM Based Electric Energy Meter

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PROJECT PICTURE


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TABLE OF CONTENTS

i. Front page - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -1ii. Abstract - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3

iii. Scope Of the Project - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -4iv. Acknowledgements - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 5v. Project Picture - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -6

CHAPTER 11. 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 22. Wireless Telemetry - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -17 2.1 Wireless telemetry - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -18 2.2 Automated meter reader - - - - - - - - - - - - - - - - - - - - - - - - - - - - 19

CHAPTER 33 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

CHAPTER 44 Introduction to Microcontroller - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -47 4.1 What is a Microcontroller - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -48


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4.1.1 Arduino - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -51 4.1.2 Platforms from Parallax, Inc - - - - - - - - - - - - - - - - - - - - - - - - - - 51 4.1.3 PICAXE - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 51 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

CHAPTER 66 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 77 Future Advancements in Project - - - - - - - - - - - - - - - - - - - - - - - - - - - - -71 7.1 Future Advancement in Project - - - - - - - - - - - - - - - - - - - - - - - - - - - 72 7.1 Duplex Communication - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 72 7.2 Power Shut Down - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 73


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7.3 Data Storage - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 74 7.4 Composite/Multi phases meter - - - - - - - - - - - - - - - - - - - - - - - - - - - -75 7.5 Networking - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 76

APPENDICESAppendix I - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -77Appendix II - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 84

Appendix III - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - -- - - 85 Acronyms- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 94 References - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 96

CHAPTER NO.1

BACKGROUND AND INTRODUCTION


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Important Points:

Purpose of the project Scope of the project Overview of Wireless telemetry 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:


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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, 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.


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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 earthquake status monitoring

Border access control

Monitoring of water, gas or oil pipelines/facilities

1.6 - AUTOMATED METER READER

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.


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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

specific model of mobile phone or GSM modem.

A destination to send a short message to, or receive a message

from.

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


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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

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:


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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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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.


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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. Following hard wave was used for

the implementation of the project.

2 Mobile phone

Energy meter

PIC Programmer

2 Data cables

PIC 16F877A Microcontroller

LCD


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INTERFACE

Breadboard

Optocoupler

Shimmit trigger

Resistors, Capacitors, Inductors, Vero board, Soldering Machine

1.8.6 - Cost of the Project in PKRS:

COMPONENTS PRICE

Energy Meter 850

Opto-coupler 50

Power Supply 100

Mobile 900

PIC 16F877A 240

Ziff Socket 90

Miscellaneous 200

Total 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 earthquake status monitoring

Border access control

Monitoring of water, gas or oil pipelines/facilities

It is often tempting to consider addressing a telemetry requirement with

a standard-based 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


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A custom-designed, application-specific telemetry system should

result in the optimum solution for a given application because

the correct trade-offs 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


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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:

o Minimizing the need to access customer property

to read meters

o Reducing customer complaints and damage

claims resulting from monthly visits to customer

site

o Call resolution improvement – billing complaint

calls will 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 and landscaping

Improved billing accuracy

A reduction in operational costs

There are several AMR technologies in today's market, ranging from

walk-by, drive-by, 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


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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 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


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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.

CHAPTER NO.3

INTRODUCTION TO GSM


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Important Points:

Basic concepts of GSM

Basic components of GSM

Network switching system

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


23

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).


24

Fig 3.1: Showing architecture of GSM network


25

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


26

These devices are mounted in a vehicle and the antenna is

physically mounted on the outside of the vehicle.


27

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


28

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

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

POWER CLASSPOWER

OUTPUT(Watts)1 20(Not Used Now)

2 8

3 5

4 2

5 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.


29

Subscriber Authentication Key (Ki)

This is used to authenticate the SIM card.

Mobile Subscriber International Services Digital Network

(MSISDN) Number

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


30

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.

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.


31

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.


32

BSS Functionality Control BSS Functionality Control

Terrestrial Channel Management

BSC EncryptionBSC/BTS

Channel Allocation BSC PagingBSC/BTS

Radio Channel Management

BSCControl Channel Management

BSC/BTS

Channel Configuration Management

BSCMeasurement Reporting

BTS

Handover Control BSCChannel Coding/Decoding

BTS

Frequency Hopping BSC/BTS Timing Advance BTS

Traffic Channel Management

BSC/BTSIdle Channel Observation

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 BTS

Control one or more BTS Contains RF hardware

Switches traffic and signaling to\from the BTS and MSC

Limited control functionality

Connects terrestrial channels and circuits on air interface

Supports 1 or more cells

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


33

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 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.


34

Fig 3.5: Showing BSS configuration

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


35

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.

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


36

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

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


37

subscriber facilities that it offers, the MSC has to be capable of fulfilling

many additional functions.

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


38

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

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


39

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)

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.


40

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.

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


41

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.

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.


42

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).

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


43

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)


44

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.

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.


45

Fig 3.9: Authentication Process

Echo Canceller (EC)

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


46

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 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


47

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

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


48

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.


49

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


50

Fig 3.11: Network in reality


51

CHAPTER NO.4

INTRODUCTION TO MICROCONTROLLER

Important points:

What is a microcontroller?

PIC Microcontroller


52

Pin Configuration

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 cost-effectiveness, 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:


53

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)

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.


54

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 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


55

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.


56

http://en.wikipedia.org/wiki/PIC_microcontroller

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 source-level 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


57

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.

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 multi-tasking, 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.


58

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 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.


59

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 mid-range cores), any register move had to be

through the accumulator.

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


60

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 8-bit (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.

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


61

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

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

cycle)


62

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

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 16-bit Capture input; max resolution 12.5 ns

o 16-bit Compare; max resolution 200 ns

o 10-bit PWM

Synchronous Serial Port with two modes:

o SPI Master

o I2C Master and Slave

USART/SCI with 9-bit address detection

Parallel Slave Port (PSP)


63

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 2 analog comparators

o Programmable on-chip voltage reference module

o Programmable input multiplexing from device inputs and

internal VREF

o Comparator outputs are externally accessible.

CHAPTER NO.5

SOFTWARE TOOLSDesign & Fabrication of GSM Based Electric Energy Meter

64

Important Points:

Visual Basic

Microsoft Office Access

Crystal ReportIn 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


65

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

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


66

http://en.wikipedia.org/wiki/GUI

http://en.wikipedia.org/wiki/Windows_API

http://en.wikipedia.org/wiki/Software_component

http://en.wikipedia.org/wiki/VBScript

http://en.wikipedia.org/wiki/Visual_Basic_for_Applications

http://en.wikipedia.org/wiki/Scripting_languages

http://en.wikipedia.org/wiki/ActiveX

http://en.wikipedia.org/wiki/ActiveX_Data_Objects

http://en.wikipedia.org/wiki/Remote_Data_Objects

http://en.wikipedia.org/wiki/Data_Access_Objects

http://en.wikipedia.org/wiki/Database

http://en.wikipedia.org/wiki/Graphical_user_interface

http://en.wikipedia.org/wiki/Graphical_user_interface

http://en.wikipedia.org/wiki/Rapid_application_development

http://en.wikipedia.org/wiki/BASIC_programming_language

http://en.wikipedia.org/wiki/Component_Object_Model

http://en.wikipedia.org/wiki/Microsoft

http://en.wikipedia.org/wiki/Integrated_development_environment

http://en.wikipedia.org/wiki/Event_driven_programming_language

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

event handlers. For example, a drop-down combination box will


67

http://en.wikipedia.org/wiki/ActiveX_Control

http://en.wikipedia.org/wiki/Event_handler

http://en.wikipedia.org/wiki/Attribute

http://en.wikipedia.org/wiki/Drag_and_drop

http://en.wikipedia.org/wiki/Microsoft_Windows

http://en.wikipedia.org/wiki/Windows_2000

http://en.wikipedia.org/wiki/Visual_Basic#Timeline%23Timeline

http://en.wikipedia.org/wiki/Visual_Basic#Timeline%23Timeline

http://en.wikipedia.org/wiki/Computer_code

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


68

http://en.wikipedia.org/wiki/MSDE

http://en.wikipedia.org/wiki/Visual_Basic_for_Applications

http://en.wikipedia.org/wiki/SQL

and may be used with Access as an alternative to the Jet Database

Engine.

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 ODBC-

compliant 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


69

http://en.wikipedia.org/wiki/Visual_Basic


http://en.wikipedia.org/wiki/Microsoft

http://en.wikipedia.org/wiki/Original_Equipment_Manufacturer

http://en.wikipedia.org/wiki/Microsoft_Visual_Studio

http://en.wikipedia.org/wiki/Business_intelligence

http://en.wikipedia.org/wiki/ODBC

http://en.wikipedia.org/wiki/Back_End_database


http://en.wikipedia.org/wiki/List_of_relational_database_management_systems

http://en.wikipedia.org/wiki/Scale_(computing)

http://en.wikipedia.org/wiki/Rapid_application_development

http://en.wikipedia.org/wiki/Active_Server_Pages

http://en.wikipedia.org/wiki/IIS

http://en.wikipedia.org/wiki/Ad_hoc

http://en.wikipedia.org/wiki/Microsoft_Jet_Database_Engine

http://en.wikipedia.org/wiki/Microsoft_Jet_Database_Engine

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.

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 third-party 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.


70

http://www.kenhamady.com/bookmarks.html

http://www.businessobjects.com/products/reporting/crystalreports/viewer/en/default.asp



http://en.wikipedia.org/wiki/Comma-separated_values

http://en.wikipedia.org/wiki/Text

http://en.wikipedia.org/wiki/Microsoft_Excel

http://en.wikipedia.org/wiki/Portable_Document_Format

Bill Calculation software used simple tools for developing this software.

CHAPTER NO.6

HARDWARE DETAILS


71

Important points:

Energy Meter

Optocoupler

Power Supply

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


72

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.

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 ABB-USA.

MC8 Single Phase Meter

Parameters Values

Voltage 220-240V

Current (Nominal) 10, 20, 40A

Current (Maximum)

40, 60, 80, 100A

TBL Poly-Phase Meter

Parameters Values

Voltage 3x200/400V

Current (Nominal) 15A

Current (Maximum) 90A

6.1.3 - Technology:


73

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 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.


74

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 = 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.


75

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.

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:


76

6.4 - LC CIRCUIT:

A specially designed LC circuit is placed right after the power supply

block in order to remove unwanted signal from the power supply block

that is, at deregulation of voltage there are some ripples and additive

noise that comes into action and may disrupt the whole function of the

circuit. This LC circuit is used to overcome such difficulties and thus

provide a noise free signal at the other end.

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.

6.5 - VOLTAGE REGULATOR (LM 311):

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 voltage regulators’ specifications.


77

Voltage Source

Transformer

Regulator

LC Circuit

Load

Capacitor

Rectifier

The voltage regulator (LM 311) used in our case has the following

specifications:

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


78

FUTURE ADVANCEMENTS IN PROJECT

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


79

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 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 walkie-talkie

style.

Fig 7.1: A simple illustration of a half-duplex communication system.

A full-duplex system allows communication in both directions, and unlike

half-duplex, allows this to happen simultaneously Examples: Telephone,

Mobile Phone, etc.


80

http://en.wikipedia.org/wiki/Mobile_Phone

http://en.wikipedia.org/wiki/Telephone

http://en.wikipedia.org/wiki/IP_Multicast

http://en.wikipedia.org/wiki/Citizens'_band_radio

http://en.wikipedia.org/wiki/Radio

http://en.wikipedia.org/wiki/Television

http://en.wikipedia.org/wiki/Simplex_circuit

http://en.wikipedia.org/wiki/Image:HalfDuplex.JPG

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

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


81

http://en.wikipedia.org/wiki/Image:FullDuplex.JPG

http://www.acclaimimages.com/usepolicy.html

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.

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


82

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.

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:


83

http://www.acclaimimages.com/usepolicy.html

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.

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};


84

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;

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);


85

PORT = ((4*data & 252) | 2);

delay(1);


delay(2);

}

void lcd_mes(const unsigned char data1)

{

PORT = ((data1/4 & 252) | 1);

delay(1);

PORT = (PORT | 3);

delay(1);


PORT = ((4*data1 & 252) | 3);

delay(1);


delay(2);


}

///////////////////////////////////////////////////////////////////

/*------------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++); //sendind string

}

}

///////////////////////////////////////////////////////////////////

/*------------- LCD INTEGER AND HEX FUNCTION ----------------*/

void lcd_int(unsigned long int_value)


86

{

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;

}

for(loop=0;loop<11;loop++){

lcd_mes(ascii_str[loop]); //sendind

string

}

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) //initialises display to be on, clear etc

{

ADCON0=0X00; // A2D off

ADCON1=0X07; // A2D off

TRIS =0X00; // Data port init

PORT =0X08;

delay(180);

delay(45);


87

PORT=PORT + 2; //First initialization

delay(15);

PORT=0X08;

// delay(45);

// PORT=PORT + 2; //First initialization

// delay(15);

// PORT=0X08;

lcd_write (0x28); //set display, Data length 4-bit, 2-line,

5x8dots

lcd_write (0x0C); //Display on, cursor off, Blinking off

lcd_write (0x06); //Entry Mode Set, Increment Mode, Display

Shift off

}

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; //0 = Selects 8-bit transmission

SPBRG = 64;

BRGH = 1; //BRGH: High Baud Rate Select bit (1 = High

speed)


88

SYNC = 0; //SYNC: USART Mode Select bit (0 =

Asynchronous 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)

{

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;


89

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_int(TEnergy/3);

lcd_message(" kWh");

INTF=0;

INTE=1;

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);


90


lcd_int(TEnergy/3);

delay1(20);

RB3 = 1;

send(gs,22);

delay1(1);

send(ascii_str,16);

RB2 = 0; RB3 = 0;

delay1(20);

}

}

static void interrupt inter (void)

{

if(INTF==1){

INTF = 0;

RB1 = !RB1;

TempTEnergy=TEnergy;

PICEEPROM_WRITE(0,TempTEnergy/16777216);

TempTEnergy=TempTEnergy%16777216;





PICEEPROM_WRITE(3,TempTEnergy);

TEnergy++;

}

}

Appendix II


91

Circuit Diagram

Appendix III


92

3.1 - BASIC CONCEPTS OF GSM

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.


93

3.1.1.1 - Frequency Range

Receive(Uplin

k)

(MHz)

Transmit(Downlin

k)

(MHz)

Separation B\

W Uplink &

Downlink(MHz

)

ARFC

N

GSM 900 890-915 935-960 45 124

EGSM90

0

880-915 925-960 45 174

GSM180

0

1710-1785 1805-1880 95 374

PCS

1900

1850-1910 1930-1990 80 299

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


94

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.

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.


95

Fig 3.1: Showing large cells geometry

Fig 3.2: Showing large cells geometry

3.1.3 - Frequency re-use


96

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

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.


97

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.

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.


98

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 densely populated areas, or


99

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 re-use pattern he may split the frequencies up as

follows:


100

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


101

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

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


102

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

B: BSS (Base Station System) BTS (Base Transceiver Station)

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)


103

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)

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


104

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/radio-

communication.shtml

en.wikipedia.org/wiki/GSM

www.gsmworld.com

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, Marie-Bernadette 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


105

http://books.google.com.pk/books?id=W6m7NC0nvE8C&dq=Book+on+Optocoupler&pg=PA117&ots=C1HR0kbOES&sig=3oDQ1zf4QbeGo2pevRRmK9Npt1I&prev=http://www.google.com.pk/search%3Fhl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla%253Aen-US%253Aofficial%26hs%3Dbw3%26q%3DBook%2Bon%2BOptocoupler%26btnG%3DSearch%26meta%3D&sa=X&oi=print&ct=result&cd=2&cad=legacy

http://books.google.com.pk/books?id=XYwuCq5u2oEC&dq=Microcontroller&ots=d82sbgd2S5&sig=UGUIXI7uF0w26cwg-qydJg-m660&prev=http://www.google.com.pk/search%3Fq%3DMicrocontroller%26ie%3Dutf-8%26oe%3Dutf-8%26aq%3Dt%26rls%3Dorg.mozilla:en-US:official%26client%3Dfirefox-a&sa=X&oi=print&ct=result&cd=3&cad=legacy

http://books.google.com.pk/books?id=v9qwbBalahoC&dq=Microcontroller&ots=5HHBtSU_9g&sig=S_K5QALiRKt2lxAq5qefxP3DiN4&prev=http://www.google.com.pk/search%3Fq%3DMicrocontroller%26ie%3Dutf-8%26oe%3Dutf-8%26aq%3Dt%26rls%3Dorg.mozilla:en-US:official%26client%3Dfirefox-a&sa=X&oi=print&ct=result&cd=1&cad=legacy

http://books.google.com.pk/books?id=yBVWAAAACAAJ&dq=Books+on+GSM

http://books.google.com.pk/books?id=OEBgAAAACAAJ&dq=Books+on+GSM

http://www.national.com/pf/LM/LM317.html

http://www.jaycar.com.au/images_uploaded/optocoup.pdf

http://www.microcontroller.com/

http://www.iec.org/online/tutorials/gsm/

http://www.gsmworld.com/

http://www.active-robots.com/products/radio-solutions/radio-communication.shtml

http://www.active-robots.com/products/radio-solutions/radio-communication.shtml

http://www.novatelwireless.com/solutions/telemetry.html

http://instruct1.cit.cornell.edu/courses/ee476/FinalProjects/s2005/mpd25_yl293/476FinPrj/INDEX.HTM

http://instruct1.cit.cornell.edu/courses/ee476/FinalProjects/s2005/mpd25_yl293/476FinPrj/INDEX.HTM


106

Report Project 1

Documents

Transcript of Report Project 1