2g n 3g planning doc

Industrial report iN:

RF LINK DESIGN FOR 2G AND 3G

Submitted in the practical fulfilment for the award of degree of bachelor of

technology in

ELECTRONICS AND COMMUNICATION ENGINEERING

From

MAHARISHI DAYANAND UNIVERSITY

(ROHTAK)

AT

Submitted by:

AMBER KHANNA

BHUMIKA KATYAL

RASHMI KURUP

RF link design for 2G and 3G

AIRCEL LIMITED P age - 1 -

ACKNOWLEDGEMENT

I would like to express my gratitude and appreciation to all those who gave me the possibility to

complete this report. A special thanks to our final year project co-guide at AIRCEL, Mr. Amit

Mittal and Ms. Uma Reddy, whose help, stimulating suggestions and encouragement, helped

me to coordinate my project especially in writing this report.

I would also like to acknowledge with much appreciation the crucial role of the staff of AIRCEL

INDIA, who gave the permission to use all required equipments, computer systems and the

necessary material to complete my project.

I would like to express my sincere thanks and heart full gratitude to Mr. Dipayan Panjafor his

immense support & guidance whenever needed during the course of my training .I would also

like to extend my gratitude to the whole staff of Aircel India for providing all the required data

and information and helping me in the success of the training.

This work could not have been completed without the indispensable assistance rendered to us by

Mr. Nitin Tyagi for providing us numerous facilities to study their resources.

.



TABLE OF CONTENTS

Chapter I

1. Company profile .............................................................................................................. 4

1.1. Early history and timeline ................................................................................................ 5

1.2. Core business ...................................................................................................................... 6

1.3. Key people .......................................................................................................................... 8

Chapter II

2. Introduction to mobile communication ......................................................................... 10

2.1. Basic architecture of GSM ............................................................................................. 11

2.2. GSM interfaces ................................................................................................................. 22

Chapter III

3. Wireless concepts .......................................................................................................... 28

3.1. Basic definitions for frequency concepts ...................................................................... 32

Chapter IV

4. Features of GSM ............................................................................................................ 33

4.1. Base station identity code ............................................................................................... 35

Chapter V

5. Channel concept ............................................................................................................ 37

5.1. Data services in GSM ....................................................................................................... 39

Chapter VI

6. GPRS Architechture .......................................................................................................... 41

6.1. GPRS network element ................................................................................................... 41

6.2. Security services in GPRS ................................................................................................ 42

Chapter VII

7. Introduction to RF planning .......................................................................................... 44

7.1. Tools used for RF planning ............................................................................................ 44

7.2. Basic definition used in RF propagation ...................................................................... 47

7.3. Propagation losses…………….. ................................................................................... 49



Chapter VIII

8. RF planning procedures ............................................................................................ 54

8.1. Initial Survay. ................................................................................................................... 55

8.2. Initial design ..................................................................................................................... 56

8.3. Selection of sites .............................................................................................................. 57

Chapter IX

9. RF planning tools used

9.1. Mentum Planet ................................................................................................................. 64

Chapter X

10. Need of advanced systems ...................................................................................... 79

10.1. Spread spectrum .............................................................................................. 84

10.2. WCDMA system…………………………............…………………………………. 87

11 RF planning for Patna 3G

11.1 Screen Shots for Planning........................................................................................95

References

Reference……………………………………………………………………118



ABSTRACT

The project titledRF link design for 2G and 3G is being actively done in the Aircel Limited, Team-RF Planning, as a part of Four months Internship.

The Internship program consists of RF Planning fundamentals, i.e. how an

information is transferred from auser equipment to the core mobile networkbased

on GSM,CDMA,WCDMA, structure of the network, the basic functionality of the

devices, tools and process and a brief session on planning management. It also

includes a brief explanation of the live projects undertaken.

Here we also worked on a simulation software(Mentum Planet, Map Info

Professional) which acts as a backbone for the radio network in a mobile system.



COMPANY PROFILE

Aircel group is an Indian mobile network operator Headquartered in Gurgaon that provides

wireless voice, messaging and data services in India. It is a joint venture between Maxis

Communications Berhad of Malaysia, whose current shareholders are the Reddy family of

Apollo Hospitals Group of India, with Maxis Communications holding a majority stake of

74%. Aircel commenced operations in 1999 and today is the leading mobile operator in Tamil

Nadu, Assam, North-East India and Chennai.

It is India’s fifth largest GSMmobile service provider and seventh largest mobile service

provider (both GSM and CDMA) with a subscriber base of over 63.35 million, as of December

2012. It has a market share of 7.33% among wireless operators (includes GSM, CDMA, and

FWP operators) in the country.

Aircel has also obtained permission from the Department of Telecommunications (DoT) to

provide International Long Distance (ILD) and National Long Distance (NLD) telephony

services. It also has the Largest service in Tamil Nadu.



EARLY HISTORY AND TIMELINE

1999:- Started as a Regional Player in Tamil Nadu.

Aircel started as a regional player in Tamil Nadu in 1999 by Chinnakannan

Sivasankaran.Soon, it became the leading operator in Tamil Nadu.

2005:- 74% stake Purchased by Malaysian Telecom Giant Maxis Communication

Companys Rapid Growing popularity attracted foreign investments

and Malaysian operator Maxis Communications bought a 74 percent stake in the company in

2005 from its Indian owner Chinnakannan Sivasankaran.

2010:- Company bought 3G and Wireless Broadband (BWA)

In 2010, the company bought 3G and wireless broadband (BWA) spectrum in 13 and 8 circles

respectively in the 2010 spectrum auction. It paid US$ 1.44 billion ( 79.1 billion) for the 3G

spectrum and US$ 0.76 billion ( 49.76 billion) for BWA.

2012:- Test run for 4G in Hyderabad

November 2012:- 1 million 3G Customers

December 2012:- 63.35 million 2G customers

2013:- Expected to launch 4G circle in Chennai.



Core Business

Fig. 1 Core Business

Core Businesses

2G Telecom Service

3G Telecom Service

Wireless Broadband(BWA)

Aircel Buisness Solutions



3G Coverage

Aircel 3G spectrum is present in 13 states:-

1.) Andhra Pradesh,

2.) Karnataka,

3.) Tamil Nadu,

4.) Kolkata,

5.) Kerala,

6.) Punjab,

7.) Uttar Pradesh (East),

8.) West Bengal,

9.) Jammu & Kashmir,

10.) Bihar,

11.) Orissa,

12.) Assam

13.) North East

Aircel Business Solutions

Aircel Business Solutions (ABS), part of Aircel, sells enterprise solutions such as Multiprotocol

Label Switching Virtual Private Networks (MPLS VPNs), Voice over Internet

Protocol (VoIP) and managed video services on wireless platforms including WiMAX.



Key people

Chief Operating Officer :- Dr. Kaizad Heerjee

Chief Financial Officer :- Mr. Anup Vikal

Head Operating Division :- Mr. Jean Pascal

Annual Revenue

Aircel generates an annual Revenue of 1.159 billion US Dollars.

Major Stake Holders

74% stake by Malaysian Telecom Giant Maxis Communication Behrad.

26% Stake by Owner of Apollo Hospitals Mr. Reddy



Introduction

A connection between two people a caller and the called person is the basic service of all

telephone networks. To provide this service, the network must be able to set up and maintain a

call, which involves a number of tasks: identifying the called person, determining the location,

routing the call, and ensuring that the connection is sustained as long as the conversation lasts.

After the transaction, the connection is terminated and (normally) the calling user is charged for

the service he has used.

In a fixed telephone network, providing and managing connections is a relatively easy process,

because telephones are connected by wires to the network and their location is permanent from

the networks’ point of view. In a mobile network, however, the establishment of a call is a far

more complex task, as the wireless (radio) connection enables the users to move at their own free

will providing they stay within the network's service area. In practice, the network has to find

solutions to three problems before it can even set up a call:

Fig.2. Information required by a mobile communications network

In other words, the subscriber has to be located and identified to provide him/her with the

requested services. In order to understand how we are able to serve thesubscribers, it is

necessary to identify the main interfaces, the subsystems and network elements in the GSM

network, as well as their functions.

•Where is thesubscriber

•Who is thesubscriber

•What does thesubscriber want

Information aboutthe subscriber



BASIC ARCHITECTURE OF GSM

Fig3 Basic Architecture of GSM

The GSM network is called Public Land Mobile Network (PLMN). It is organised in three

subsystems:

Base Station Subsystem (BSS)

Network Switching Subsystem (NSS)

Network Management Subsystem (NMS)



Mobile Station (MS)

In GSM, the mobile phone is called Mobile Station (MS). The MS is a combination of terminal

equipment and subscriber data. The terminal equipment as such is called ME (Mobile

Equipment) and the subscriber's data is stored in a separate module called SIM (Subscriber

Identity Module).

Therefore, ME + SIM = MS.

Fig4. Inserting a SIM card in a mobile phone

From the user’s point of view, the SIM is certainly the best-known database used in a GSM

network. The SIM is a small memory device mounted on a card and contains user-specific

identification. The SIM card can be taken out of one mobile equipment and inserted into another.

In the GSM network, the SIM card identifies the user just like a traveller uses a passport to

identify himself.

The SIM card contains the identification numbers of the user and a list of available networks.

The SIM card also contains tools needed for authentication and ciphering. Depending on the type

of the card, there is also storage space for messages, such as phone numbers. A home operator

issues a SIM card when the user joins the network by making a service subscription. The home

operator of the subscriber can be anywhere in the world, but for practical reasons the subscriber

chooses one of the operators in the country where he/she spends most of the time.



SIM

• The SIM is a removable card that plugs into the ME.

• It identifies the mobile subscriber and provides information about the service that the subscriber

should receive.

• The SIM contains several pieces of information

– International Mobile Subscribers Identity ( IMSI ) - This number identifies the mobile

subscriber. It is only transmitted over the air during initialising.

– Temporary Mobile Subscriber Identity ( TMSI ) - This number also identifies the subscriber. It

can be alternatively used by the system. It is periodically changed by the system 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.

– Subscribers Authentication Key ( Ki ) - This is used to authenticate the SIM card.

Mobile Station International Standard Data Number ( MSISDN ) - This is the telephone number

of the mobile.

• Mostof the data contained within the SIM is protected against reading (eg Ki ) or alterations after

the SIM is issued.

• Some of the parameters ( eg. LAI ) will be continously updated to reflect the current location of

the subscriber.

• The SIM card can be protected by use of Personal Identity Number ( PIN ) password.

• The SIM is capable of storing additional information such as accumulated call charges.

FULL SIZE SIM CARD

Fig 5 Full size sim card



Mobile Station International Subscribers Dialling Number( MSISDN ) :

• Human identity used to call a MS

• The Mobile Subscriber ISDN (MSISDN) number is the telephone number of the MS.

• This is the number a calling party dials to reach the subscriber.

• It is used by the land network to route calls toward the MSC.

CC = Country code

NDC = National Destination Code

SN = Subscriber Number

International Mobile Subscribers Identity ( IMSI ) :

• Network Identity Unique to a MS

• The International Mobile Subscriber Identity (IMSI) is the primary identity of the subscriber

within the mobile network and is permanently assigned to that subscriber.

• The IMSI can be maximum of 15 digits.

MCC= Mobile Country Code (3 digits)

MNC=Mobile network Code (2 digits)

MSIN=Mobile Subscriber Identity Number

Temporary Mobile Subscribers Identity ( TMSI ) :

• The GSM system can also assign a Temporary Mobile Subscriber Identity (TMSI).

• After the subscriber's IMSI has been initialized on the system, the TMSI can be used for sending

messages backwards and forwards across the network to identify the subscriber.



• The system automatically changes the TMSI at regular intervals, thus protecting the subscriber

from being identified by someone attempting to monitor the radio channels.

• The TMSI is a local number and is always allocated by the VLR.

• The TMSI is maximum of 4 octets.

International Mobile Equipment Identity ( IMEI ) :

• IMEI is a serial number unique to each mobile

• Each MS is identified by an International Mobile station Equipment Identity (IMEI) number

which is permanently stored in the Mobile Equipment.

• On request, the MS sends this number over the signalling channel to the MSC.

• The IMEI can be used to identify MSs that are reported stolen or operating incorrectly.

TAC FAC SNR SP

6 2 6 1



BASE STATION SUBSYSTEM

The Base Station Subsystem is responsible for managing the radio network, and it is controlled

by an MSC. Typically, one MSC contains several BSSs. A BSS itself may cover a considerably

large geographical area consisting of many cells(a cell refers toan area covered by one or more

frequency resources). The BSS consists of the following elements:

BSC Base Station Controller

BTS Base Transceiver Station

TRAU Transcoder and Rate Adaptation Unit (sometimes also called TC (Transcoder))

Fig6. The Base Station Subsystem (BSS)

Some of the most important BSS tasks are listed in the following:

Radio path control

In the GSM network, the Base Station Subsystem (BSS) is the part of the network taking care of

radio resources, that is, radio channel allocation and quality of the radio connection.

Synchronisation

The BSS uses hierarchical synchronisation, which means that the MSC synchronises the BSC,

and the BSC further synchronises the BTSs associated with that particular BSC. Inside the BSS,

synchronisation is controlled by the BSC. Synchronisation is a critical issue in the GSM network

due to the nature of the information transferred. If the synchronisation chain is not working

correctly, calls may be cut or the call quality may not be the best possible. Ultimately, it may

even be impossible to establish a call.

Air- and A-interface signalling

In order to establish a call, the MS must have a connection throughhe the BSS.

BTS

TC

BSC

BSC

TC

BTS

BTS



Connection establishment between the MS and the NSS

The BSS is located between two interfaces, the air- and the A-interface. The MS must have a

connection through these two interfaces before a call can be established. Generally speaking, this

connection may be either a signalling connection or a traffic (speech, data) connection.

Mobility management and speech transcoding

BSS mobility management mainly covers the different cases of handovers. These handovers and

speech transcoding are explained in later sections.

Let us now have a closer look at each of the individual network elements (BSC, BTS, and

Transcoder.

Base Station Controller (BSC) The BSC is the central network element of the BSS and it controls the radio network. It has

several important tasks, some of which are presented in the following:

Connection establishment between the MS and the NSS

All calls to and from the MS are connected through the switching functionality of the BSC.

Mobility management

The BSC is responsible for initiating the vast majority of all handovers, and it makes the handover decision based on, among others, measurement reports sent by the MS during a call.

Statistical raw data collection

Information from the Base Transceiver Stations, Transcoders, and BSC are collected in the BSC

and forwarded via the DCN (Data Communications Network) to the NMS (Network

Management Subsystem), where they are post-processed into statistical views, from which the

network quality and status is obtained.

Air- and A-interface signalling support

In the A-interface, SS#7 (Common Channel Signalling System No. 7) is used as the signalling

language, while the environment in the air interface allows the usage of a protocol adapted from

ISDN standards, namely LAPDm (Link Access Protocol on the ISDN D Channel, modified

version). Between the Base Transceiver Station and the BSC (Abis interface), a more

standardised LAPD protocol is used. The BSC also enables the transparent signalling connection

needed between the MSC/VLR and the MS.

BTS and TRAU control

Inside the BSS, all the BTSs and TCs are connected to the BSC(s). The BSC maintains the BTSs.

In other words, the BSC is capable of separating (barring) a BTS from the network and



collecting alarm information. TRAUs are also maintained by the BSC, that is, the BSC collects

alarms related to the transcoders.

Base Transceiver Station (BTS) The BTS is the network element responsible for maintaining the air interface and minimising the

transmission problems (the air interface is very sensitive for disturbances). This task is

accomplished with the help of some 120 parameters. These parameters define exactly what kind

of BTS is in question and how MSs may "see" the network when moving in this BTS area.

The BTS parameters handle the following major items: what kind of handovers (when and why),

paging organisation, radio power level control, and BTS identification. The BTS has several very

important tasks, some of which are presented in the following.

Fig7.Nokia MetroSite Base Transceiver Station

Air interface signalling

A lot of both call and non-call related signalling must be performed in order for the system to

work. One example is that when the MS is switched on for the very first time, it needs to send

and receive a lot of information with the network (more precisely with the VLR) before we can

start to receive and make phone calls. Another example is the signalling required to set up both

mobile originated and mobile terminated calls. A third very important signalling in mobile

networks is the need to inform the MS when a handover is to be performed (and later when the

MS sends a message in the uplink direction telling the network that the handover is completed.

Later in this chapter, we will have a closer look at all of these different cases.



Ciphering

Both the BTS and the MS must be able to cipher and decipher information in order to protect the

transmitted speech and data in the air interface.

Speech processing

Speech processing refers to all the functions the BTS performs in order to guarantee an error-free

connection between the MS and the BTS. This includes tasks like speech coding (digital to

analogue in the downlink direction and vice versa), channel coding (for error protection),

interleaving (to enable a secure transmission), and burst formatting (adding information to the

coded speech / data in order to achieve a well-organised and safe transmission).

Fig 8. Speech in the BSS

Modulation and De-modulation

User data is represented with digital values 0 and 1. These bit values are used to change one of

the characteristics of an analogue radio signal in a predetermined way. By altering the

characteristic of a radio signal for every bit in the digital signal, we can "translate" an analogue

signal into a bit stream in the frequency domain. This technique is called modulation. In GSM,

Gaussian Minimum Shift Keying (GMSK) is applied.

The base station can contain several TRXs (Transceivers), each supporting one pair of

frequencies for transmitting and receiving information. The BTS also has one or more antennas,

which are capable of transmitting and receiving information to/from one or more TRXs. The

antennas are either omnidirectional or sectorised. It also has control functions for Operation and

Maintenance (O&M), synchronisation and external alarms, etc.

Speech, 64 kbps

compression Channel Coding

= redundancy

Interleavingand ciphering

TDMA burst formatting

GMSKmodulation

22.8kbit/s

13kbit/s

33.8kbit/s

22.8kbit/sAir

Interface

MSC TRAU TRAU BTS



Fig 9.Omnidirectional and sectorised cells

Transcoder and Rate Adaptation Unit (TRAU) In the air interface (between MS and BTS), the media carrying the traffic is a radio frequency.

To enable an efficient transmission of digital speech information over the air interface, the digital

speech signal is compressed. We must however also be able to communicate with and through

the fixed network, where the speech compression format is different. Somewhere between the

BTS and the fixed network, we therefore have to convert from one speech compression format to

another, and this is where the Transcoder comes in.

Fig10. Location of Transcoder and Submultiplexer

Omnidirectional BTS

f1,f2, f3

3 sectorised BTS

2 sectorised BTS

f2

f1, f2

f5, f6

f1

f3, f4

BTSBTS

BTS

BTS

BTS BTS

A InterfaceA ter’ Interface

A ter Interface

MSC

SM2M

TC

TC

TC

TC

Transcoder andSubmultiplexer (TCSM)

BSC



For transmission over the air interface, the speech signal is compressed by the mobile station to

13 kbit/s (Full Rate and Enhanced Full Rate), 5.6 kbit/s (Half Rate), or 12.2 kbit/s

(Enhanced Full Rate). However, the standard bit rate for speech in the PSTN is 64 Kbits/s. The

modulation technique is called "Pulse Code Modulation" (PCM).

The TRAU thus takes care of the change from one bit rate to another. If the TC is located as

close as possible to the MSC with standard PCM lines connecting the network elements, we can,

in theory, multiplex four traffic channels in one PCM channel. This increases the efficiency of

the PCM lines, and thus lowers the costs for the operator. When we connect to the MSC, the

multiplexed lines have to be de-multiplexed. For that reason, the Nokia solution of the TRAU is

called Transcoder and Submultiplexer (TCSM).

According to the standards, the TRAU functionality can be also implemented at the BSC and

BTS site. The most common case is the MSC site.

Another task for the TRAU is to enable DTX (Discontinuous transmission), which is used during

a call when there is nothing to transmit (no conversation). It is activated in order to reduce

interference and to save MS battery.

In the Nokia solution, the submultiplexing and transcoding functions are combined in one piece

of equipment called TCSM2E (European version) or TCSM2A (American version).

GSM Interfaces

One of the main purposes behind the GSM specifications is to define several open interfaces,

which then limit certain parts of the GSM system. Because of this interface openness, the

operator maintaining the network may obtain different parts of the network from different GSM

network suppliers. When an interface is open, it also strictly defines what is happening through

the interface, and this in turn strictly defines what kind of actions/procedures/functions must be

implemented between the interfaces.

The GSM specifications define two truly open interfaces within the GSM network. The first one

is between the Mobile Station (MS) and the Base Station (BS). This open-air interface is called

Um. It is relatively easy to imagine the need for this interface to be open, as mobile phones of all

different brands must be able to communicate with GSM networks from all different suppliers.

The second interface is located between the Mobile services Switching Centre, MSC and the

Base Station Controller (BSC). This interface is called the “A-interface”. The system includes

more than the two defined interfaces, but especially the ones within the BSS not totally open.



Fig 11. Interfaces in GSM

Following are the specified interfaces:

Um: MS - BTS (air or radio interface)

A: MSC – BSC

Abis: BSC – BTS (proprietary interface)

Ater: BSC – TRAU (sometimes called Asub) (proprietary interface)

B: MSC – VLR

C: MSC – HLR

D: HLR – VLR

E: MSC – MSC

F: MSC – EIR

G: VLR - VLR.

BSC

TC

BTS

BTS

VLR

(G)MSC

EIRHLR AC

Um

AAter

Abis

B C

D

VLR

G

F

(G)MSC

E

BSS NSS

BSC

TC

BTS

BTS

(G)MSC

Um

AAter

Abis

B C

D

VLREIR

HLR AC

VLR

G

F

(G)MSC

E

BSS NSS



NETWORKING SWITCHING SUBSYSTEM

The Network Switching Subsystem (NSS) contains the network elements MSC, GMSC, VLR,

HLR, AC and EIR.

Fig12. The Network Switching Subsystem (NSS)

The main functions of NSS are:

Call control

This identifies the subscriber, establishes a call, and clears the connection after the conversation

is over.

Charging

This collects the charging information about a call (the numbers of the caller and the called

subscriber, the time and type of the transaction, etc.) and transfers it to the Billing Centre.

Mobility management

This maintains information about the subscriber's location.

Signalling

This applies to interfaces with the BSS and PSTN.

Subscriber data handling

This is the permanent data storage in the HLR and temporary storage of relevant data in the

VLR.

VLR

GMSC

VLR

MSC

HLR

HLR

AC

EIR



Mobile services Switching Centre (MSC)

The MSC is responsible for controlling calls in the mobile network. It identifies the origin and

destination of a call (mobile station or fixed telephone), as well as the type of a call.

The MSC is responsible for several important tasks, such as the following.

Call control

MSC identifies the type of call, the destination, and the origin of a call. It also sets up,

supervises, and clears connections.

Initiation of paging

Paging is the process of locating a particular mobile station in case of a mobile terminated call (a

call to a mobile station).

Charging data collection

The MSC generates CDRs, Charging Data Records, which contain information about the

subscribers’ usage of the network.

Gateway Mobile services Switching Centre (GMSC)

The GMSC is responsible for the same tasks as the MSC, except for paging. It is needed in case

of mobile terminated calls. In fixed networks, a call is established to the local exchange, to which

the telephone is connected. But in GSM, the MSC, which is serving the MS, changes with the

subscriber’s mobility. Therefore, in a mobile terminated call, the call is set up to a well defined

exchange in the subscriber’s home PLMN. This exchange is called GMSC. The GMSC than

interacts with a database called Home Location Register, which holds the information about the

MSC, which is currently serving the MS. The process of requesting location information from

the HLR is called HLR Interrogation. Given the information about the serving MSC, the

GMSC then continues the call establishment process.

In many real life implementations, the MSC functionality and the GMSC functionality are

implemented in the same equipment, which is then just called MSC. Many operators use GMSCs

for breakout to external networks such as PSTNs.

Visitor Location Register (VLR)

In the Nokia implementation, Visitor Location Register (VLR) is integrated with the MSC

cabinet. VLR is a database that contains information about subscribers currently being in the

service area of the MSC/VLR, such as:

Identification numbers of the subscribers

Security information for authentication of the SIM card and for ciphering



Services that the subscriber can use

The VLR carries out location registrations and updates. When a mobile station comes to a new

MSC/VLR serving area, it must register itself in the VLR, in other words perform a location

update. Please note that a mobile subscriber must always be registered in a VLR in order to use

the services of the network. Also the mobile stations located in their own networks are always

registered in a VLR.

The VLR database is temporary, in the sense that the data is held as long as the subscriber is

within its service area. It also contains the address to every subscriber's Home Location Register,

which is the next network element to be discussed.

Home Location Register (HLR) HLR maintains a permanent register of the subscribers. For instance the subscriber identity

numbers and the subscribed services can be found here. In addition to the fixed data, the HLR

also keeps track of the current location of its customers. As you will see later, the GMSC asks for

routing information from the HLR if a call is to be set up to a mobile station (mobile terminated

call).

In the Nokia implementation, the two network elements, Authentication Centre (AC) and

Equipment Identity Register (EIR), are located in the Nokia DX200 HLR.

Authentication Centre (AC) The Authentication Centre provides security information to the network, so that we can verify

the SIM cards (authentication between the mobile station and the VLR, and cipher the

information transmitted in the air interface (between the MS and the Base Transceiver Station)).

The Authentication Centre supports the VLR's work by issuing so-called authentication triplets

upon request.

Equipment Identity Register (EIR) As for AC, the Equipment Identity Register is used for security reasons. But while the AC

provides information for verifying the SIM cards, the EIR is responsible for IMEI checking

(checking the validity of the mobile equipment). When this optional network element is in use,

the mobile station is requested to provide the International Mobile Equipment Identity

(IMEI) number. The EIR contains three lists:

Mobile equipment in the white list is allowed to operate normally.

If we suspect that mobile equipment is faulty, we can monitor the use of it. It is then placed in

the grey list.

If the mobile equipment is reported stolen, or it is otherwise not allowed to operate in the

network, it is placed in the black list.

Note that IMEI checking is an optional procedure, so it is up to the operator to define if and

when IMEI checking is performed. (Some operators do not even implement the EIR at all.)



Network Management Subsystem (NMS)

The Network Management Subsystem (NMS) is the third subsystem of the GSM network in

addition to the Network Switching Subsystem (NSS) and Base Station Subsystem (BSS), which

we have already discussed. The purpose of the NMS is to monitor various functions and

elements of the network.

The functions of the NMS can be divided into three categories:

Fault management

Configuration management

Performance management

These functions cover the whole of the GSM network elements from the level of individual

BTSs, up to MSCs and HLRs.

Fault management

The purpose of fault management is to ensure the smooth operation of the network and rapid

correction of any kind of problems that are detected. Fault management provides the network

operator with information about the current status of alarm events and maintains a history

database of alarms.

The alarms are stored in the NMS database and this database can be searched according to

criteria specified by the network operator.

Fig13. Fault management

Configuration management

The purpose of configuration management is to maintain up-to-date information about the

operation and configuration status of network elements. Specific configuration functions include

the management of the radio network, software and hardware management of the network

elements, time synchronisation, and security operations.



Fig14. Configuration management

Performance management

In performance management, the NMS collects measurement data from individual network

elements and stores it in a database. On the basis of these data, the network operator is able to

compare the actual performance of the network with the planned performance and detect both

good and bad performance areas within the network.



WIRELESS CONCEPTS Frequency-related specifications of the GSM systems

Table 1 Frequency -related Specification of GSM

BASIC DEFINITIONS FOR FREQUENCY CONCEPTS

1. FREQUENCY: The frequency of a radio wave is the number of times the wave oscillates per

second. Frequency is measured in Hertz (Hz), where 1 Hz indicates one oscillation per second

2.WAVELENGTH:Wavelength () is the length of one complete oscillation and is measured in

meters (m). Frequency and wavelength are related via the speed of propagation of wave which is

3x108

m/s.

Lower frequencies, with longer wavelengths, are better suited to transmission over large

distances, because they bounce on the surface of the earth and in theatmosphere.

NOTE:-Due to frequency, a BTS transmitting information at 1800

MHz with an output power of 10 Watts (W) will cover only

half the area of a similar BTS transmitting at 900 MHz.

Wavelength = Speed .

Frequency



Higher frequencies, with shorter wavelengths, are better suited to transmission over small

distances, because they are sensitive to suchproblems as obstacles in the line of the transmission

path.

1. BANDWIDTH: Bandwidth is the term used to describe the amount of frequency range allocated

to one application.

2. CHANNELS: A channel is a frequency or set of frequencies which can be allocated for the

transmission, and possibly the receipt, of information.

Fig 15 Uplink and Downlink on Radio Channel

(NETWORK to the MS)

NOTE:-As less power is required to transmit low frequency over a given

distance, therefore uplink frequencies in mobile systems are always the lower

band of frequencies this saves valuable battery power of the MSs.



3. DUPLEX DISTANCE: The use of full duplex requires that uplink and downlink transmissions

are separated in frequency by a minimum distance, called duplex distance.

4. CARRIER SEPARATION: In addition to the duplex distance, every mobile system includes a

carrier separation. This is the distance on the frequency bandbetween channels being transmitted

in the same direction.

This isrequired in order to avoid the overlapping of information in onechannel into an adjacent

channel.

In GSM the carrier separation is fixed at 200 kHz

Fig 17 Carrier Separation

5. FREQUENCY RE-USE :

These frequency re-use patterns ensure that any frequencies being re-used are located at a

sufficient distance apart to ensure that there is little interference between them.

The term “frequency re-uses distance” is used to describe the distance between two identical

frequencies in a re-use pattern. The lower the frequency re-uses distance, the more capacity will

be available in the network.

Fig 16 Duplex Distance

Fig 18 Frequency Reuse



6. TRANSMISSION RATE: The amount of information transmitted over a radio channel over a

period of time is known as the transmission rate. In GSM the net bit rate over the air interface is

270kbit/s.

7. MODULATION METHOD: At a basic level, for a carrier frequency to carry digital

information we must be able to modify the carrier waveform in some way so that it represents

digital one (1) and modify it again so that it represents digital zero (0). This modification process

is called ‘modulation’ and there are different methods available.

The modulation technique used in GSM is Gaussian Minimum ShiftKeying (GMSK) and is a

form of phase modulation, or ‘phase shiftkeying’ as it is called.

GMSK enables the transmission of 270kbit/swith in a 200KHz channel.

This gives a bit rate of 1.3 bit/s per Hz. Thisis a rather low bitrate but acceptable as GMSK

gives highinterference resistance level.

ACCESS METHOD: TIME DIVISION MULTIPLE ACCESS (TDMA)

Most digital cellular systems use the technique of Time Division Multiple Access (TDMA) to

transmit and receive speech signals.

With TDMA, one carrier is used to carry a number of calls, each callusing that carrier at

designated periods in time. These periods of time are referred to as time slots.

Information sent during one time slot is called a burst.

In GSM, a TDMA frame consists of 8 time slots. This means that aGSM radio carrier can carry 8

calls.



Fig. 19 TDMA Downlink Frame

GSM TRANSMISSION AND RECEPTION

FIG.20transmission and Reception Process



FEATURES OF GSM

INCREASED CAPACITY

• The GSM system provides a greater subscriber capacity than analogue systems.

• GSM allows 25 kHz per user, that is, eight conversations per 200 kHz channel pair (a pair

comprising one transmit channel and one receive channel).

• Digital channel coding and the modulation used makes the signal resistant to interference from

cells where the same frequencies are re-used (co-channel interference); a Carrier to Interference

Ratio (C/I) level of 12 dB is achieved, as opposed to the 18 dB typical with analogue cellular.

• This allows increased geographic reuse by permitting a reduction in the number of cells in the

reuse pattern.

AUDIO QUALITY

• Digital transmission of speech and high performance digital signal processors provide good

quality speech transmission.

• Since GSM is a digital technology, the signals passed over a digital air interface can be protected

against errors by using better error detection and correction techniques.

• In regions of interference or noise-limited operation the speech quality is noticeably better than

analogue.

USE OF STANDARDISED OPEN INTERFACES

• Standard interfaces such as C7 and X25 are used throughout the system. Hence different

manufacturers can be selected for different parts of the PLMN.

• There is a high flexibilty in where the Network components are situated.

IMPROVED SECURITY AND CONFIDENTIALITY

• GSM offers high speech and data confidentiality.

• Subscriber authentication can be performed by the system to check if a subscriber is a valid

subscriber or not.

• The GSM system provides for high degree of confidentiality for the subscriber. Calls are

encoded and ciphered when sent over air.

• The mobile equipment can be identified independently from the mobile subscriber. The mobile

has a identity number hard coded into it when it is manufactured. This number is stored in a

standard database and whenever a call is made the equipment can be checked to see if it has been

reported stolen.



CLEANER HANDOVERS

• GSM uses Mobile assisted handover techique.

• The mobile itself carries out the signal strength and quality measurement of its server and signal

strength measurement of its neighbors.

• This data is passed on the Network which then uses sophisticated algorithms to determine the

need of handover.

SUBSCRIBER IDENTIFICATION

• In a GSM system the mobile station and the subscriber are identified separately.

• The subscriber is identified by means of a smart card known as a SIM.

• This enables the subscriber to use different mobile equipment while retaining the same

subscriber number.

ENHANCED RANGE OF SERVICES

• Speech services for normal telephony.

• Short Message Service for point ot point transmission of text message.

• Cell broadcast for transmission of text message from the cell to all MS in its coverage area.

Message like traffic information or advertising can be transmitted.

• Fax and data services are provided. Data rates available are 2.4 Kb/s, 4.8 Kb/s and 9.6 Kb/s.

• Supplementary services like number identification , call barring, call forwarding, charging

display etc can be provided.

FREQUENCY REUSE

• There are total 124 carriers in GSM ( additional 50 carriers are available if EGSM band is used).

• Each carrier has 8 timeslots and if 7 can be used for traffic then a maximum of 868 ( 124 X 7 )

calls can be made. This is not enough and hence frequencies have to be reused.

• The same RF carrier can be used for many conversations in several different cells at the same

time.

• The radio carrier available are allocated according to a regular pattern which repeats over the

whole coverage area.

• The pattern to be used depends on the traffic requirement and spectrum availability.

• Some typical repeat patterns are 4/12, 7/21 etc.



Fig 21 Frequency reuse pattern

Cell Global Identity ( CGI ) :

MCC=Mobile Country Code

MNC=Mobile Network Code

LAI=location area identity

CI=cell identity

• BSIC allows a mobile station to distinguish between neighboring base stations.

• It is made up of 8 bits.

NCC = National Colour Code( Differs from operator to operator )

BCC = Base Station Colour Code, identifies the base station to help distinguish betweenCell’s

using the same BCCH frequencies



NCC = National Colour Code( Differs from operator to operator )

BCC = Base Station Colour Code, identifies the base station to help distinguish

between Cell’s using the same BCCH frequencies

CHANNEL CONCEPT

Fig 22. Channel concept

Physical channel - Each timeslot on a carrier is referred to as a physical channel. Per carrier there

are 8 physical channels.

Logical channel - Variety of information is transmitted between the MS and BTS. There are

different logical channels depending on the information sent. The logical channels are of two

types

• Traffic channel

• Control channel



GSM Control Channels

BCH ( Broadcast channels )Downlink only

Control Channels

DCCH(Dedicated Channels)Downlink & Uplink

CCCH(Common Control Chan)Downlink & Uplink

Synch.Channels

RACHRandom

Access Channel

CBCHCell Broadcast

Channel

SDCCHStandalonededicated

control channel

ACCHAssociated

Control Channels

SACCHSlow associatedControl Channel

FACCHFast AssociatedControl Channel

PCH/AGCH

Paging/Access grant

FCCHFrequency

Correction channel

SCHSynchronisation

channel

BCCHBroadcast

control channel

CHANNEL CONCEPT

Fig 23. GSM control channel

CCCH Channels (Common Control Channel)

RACH( Random Access Channel )

• Uplink only

• Used by the MS to access the Network.

AGCH( Access Grant Channel )

• Downlink only

• Used by the network to assign a signalling channel upon successfull decoding of access bursts.

PCH( Paging Channel )

• Downlink only.

• Used by the Network to contact the MS



DCCH Channels (Dedicated Control Channel)

SDCCH( Standalone Dedicated Control Channel )

• Uplink and Downlink

• Used for call setup, location update and SMS.

SACCH( Slow Associated Control Channel )

• Used on Uplink and Downlink only in dedicated mode.

• Uplink SACCH messages - Measurement reports.

• Downlink SACCH messages - control info.

FACCH( Fast Associated Control Channel )

• Uplink and Downlink.

• Associated with TCH only.

• Is used to send fast messages like handover messages.

• Works by stealing traffic bursts.

Constraints with existing network

• Data Rates too slow – about 9.6 kbps

• Connection setup time too long

• Inefficient resource utilization for bursty traffic

• Proves expensive for bursty traffic utilization

• Not efficient method for packet transfers



DATA SERVICES IN GSM

1. Data transmission standardized with only 9.6 kbit/s

– advanced coding allows 14.4 kbit/s

– not enough for Internet and multimedia applications

2. HSCSD (High-Speed Circuit Switched Data)

– already standardized

– bundling of several time-slots to get higher

AIUR (Air Interface User Rate)

(e.g., 57.6 kbit/s using 4 slots, 14.4 each)

– advantage: ready to use, constant quality, simple

– disadvantage: channels blocked for voice transmission

3. GPRS (General Packet Radio services)

– A step between GSM and 3G .

– GPRS is an overlay network over the GSM

– Allows users to transfer data and make calls at the same time.

– GPRS employs Packet switching

– Using free slots only if data packets ready to send (e.g., 115 kbit/s using 8 slots temporarily)

– Standardized by ETSI in1998, introduction 2000.

– Support for leading internet communication protocols

– Billing based on volume of data transferred

– Utilizes existing GSM authentication and privacy procedures.

– Advantage: one step towards UMTS, more flexible

– Disadvantage: more investment needed



GPRS ARCHITECTURE

Fig 24 GPRS Architecture

GPRS Network Elements

– GSN (GPRS Support Nodes)

– GGSN (Gateway GSN)

• interworking unit between GPRS and PDN (Packet Data Network)

– SGSN (Serving GSN)

• supports the MS (location, billing, security)

– GR (GPRS Register)

• user addresses

SGSN (Serving GSN)

1. Delivers data packets to mobile stations & vice-versa (via

2. Gb interface).

3. Requests user address from GR

4. Keeps track of individual MSs’ location i.e. detects and registers new GPRS MS in its serving

area

5. Responsible for collecting billing information

6. Performs security functions such as access control, Authentication

7. Connected to MSC and BSC

8. Packet Routing, Transfer & Mobility Management

9. Maintaining user profiles.



GR-GPRS Register

1. GPRS Register is integrated with GSM- Typically part of HLR

2. Maintains the GPRS subscriber data and routing information.

3. Stores current SGSN address.

4. Stores all GPRS relevant data.

GGSN(Gateway GPRS Support Node)

1. Interfaces GPRS backbone network & external packet data networks.

2. Converts the GPRS packets from SGSN to the PDP format.

3. Converts PDP addresses change to GSM addresses of the destination user.

4. Routing info for GPRS users.

5. Performs address conversion.

6. Tunnels data to a user via encapsulation.

7. Transfers data to PDN (e.g. Internet, X.25) using Gi interface.

8. Transfers data packets to SGSN via IP based GPRS backbone network ( Gn interface).

9. Many-to- many relations among SGSNs & GGSNs .

10. Stores the current SGSN address and profile of the user in its location register.

11. Performs authentication.

Security Services In GPRS

1. Authentication

2. Access control

3. User information confidentiality

4. Complete anonymous service is also possible e. g. applied for toll systems that only charge a user

via the MS independent of user’s identity.



INTRODUCTION TO RF PLANNING

• Designing a cellular system - particularly one that incorporates both Macrocellular and

Microcellular networks is a delicate balancing exercise.

• The goal is to achieve optimum use of resources and maximum revenue potential whilst

maintaining a high level of system quality.

• Full consideration must also be given to cost and spectrum allocation limitations.

• A properly planned system should allow capacity to be added economically when traffic demand

increases.

• As every urban environment is different, so is every macrocell and microcell network. Hence

informed and accurate planning is essential in order to ensure that the system will provide both

the increased capacity and the improvement in network quality where required, especially when

deploying Microcellular systems.

• RF planning plays a critical role in the Cellular design process.

• By doing a proper RF Planning by keeping the future growth plan in mind we can reduce a lot of

problems that we may encounter in the future and also reduce substantially the cost of

optimization.

• On the other hand a poorly planned network not only leads to many Network problems , it also

increases the optimization costs and still may not ensure the desired quality.

TOOLS USED FOR RF PLANNING

• Network Planning Tool

• CW Propagation Tool

• Traffic Modeling Tool

• Project Management Tool



Network Planning Tool

• Planning tool is used to assist engineers in designing and optimizing wireless networks by

providing an accurate and reliable prediction of coverage, doing frequency planning

automatically, creating neighbor lists etc.

• With a database that takes into account data such as terrain, clutter, and antenna radiation

patterns, as well as an intuitive graphical interface, the Planning tool gives RF engineers a state-

of-the-art tool to:

– Design wireless networks

– Plan network expansions

– Optimize network performance

– Diagnose system problems

• The major tools available in the market are Planet, Pegasos, Cell Cad.

• Also many vendors have developed Planning tools of their own like Netplan by Motorola, TEMS

by Ericsson and so on.

Propagaton Test Kit

• The propagation test kit consists of

– Test transmitter.

– Antenna (generallyOmni).

– Receiver to scan the RSS (Received signal levels). The receiver scanning rate should be settable

so that it satisfies Lee’s law.

– A laptop to collect data.

– A GPS to get latitude and longitude.

– Cables and accessories.

– Wattmeter to check VSWR.

• A single frequency is transmitted a predetermined power level from the canditate site.

• These transmitted power levels are then measured and collected by the Drive test kit. This data is

then loaded on the Planning tool and used for tuning models.

• Commonly Grayson’s or CHASE prop test kits are used.



Traffic Modeling Tool

• Traffic modelling tool is used by the planning engineer for Network modelling and

dimensioning.

• It helps the planning engineer to calculate the number of network elements needed to fulfil

coverage, capacity and quality needs.

• Netdim by Nokia is an example of a Traffic modelling tool.

Project Management Tool

• Though not directly linked to RF Design Planning, it helps in scheduling the RF Design process

and also to know the status of the project

• Site database : This includes RF data, site acquisition, power, civil ,etc.

• Inventory Control

• Fault tracking

• Finance Managemen



BASIC DEFINATIONS USED IN RF PROPAGATION

Isotropic RF Source

A point source that radiates RF energy uniformly in all directions (I.e.: in the shape of a sphere)

Theoretical only: does not physically exist.

Has a power gain of unity I.e. 0dBi.

Effective Radiated Power (ERP)

Has a power gain of unity i.e. 0dBi

The radiated power from a half-wave dipole.

A lossless half-wave dipole antenna has a power gain of 0dBd or 2.15dBi.

Effective Isotropic Radiated Power (EIRP)

The radiated power from an isotropic source

EIRP = ERP + 2.15 dB

• Radio signals travel through space at the Speed of Light

C = 3 * 108 meters / second

• Frequency (F) is the number of waves per second (unit: Hertz)

• Wavelength () (length of one wave) = (distance traveled in one second)

(waves in one second)

= C / F

If frequency is 900MHZ then

wavelength = 3 * 108

900 * 106

= 0.333 meters



dB

• dB is a a relative unit of measurement used to describe power gain or loss.

• The dB value is calculated by taking the log of the ratio of the measured or calculated power (P2)

with respect to a reference power (P1). This result is then multiplied by 10 to obtain the value in

dB.

dB = 10 * log10(P1/P2)

• The powers P1 ad P2 must be in the same units. If the units are not compatible, then they should

be transformed.

• Equal power corresponds to 0dB.

• A factor of 2 corresponds to 3dB

If P1 = 30W and P2 = 15 W then

10 * log10(P1/P2) = 10 * 10 * log10(30/15)

= 2

dBm

• The most common "defined reference" use of the decibel is the dBm, or decibel relative to one

milliwatt.

• It is different from the dB because it uses the same specific, measurable power level as a

reference in all cases, whereas the dB is relative to either whatever reference a particular user

chooses or to no reference at all.

• A dB has no particular defined reference while a dBm is referenced to a specific quantity: the

milliwatt (1/1000 of a watt).

• The IEEE definition of dBm is "a unit for expression of power level in decibels with reference to

a power of 1 milliwatt."

• The dBm is merely an expression of power present in a circuit relative to a known fixed amount

(i.e., 1 milliwatt) and the circuit impedance is irrelevant.}

• dBm = 10 log (P) (1000 mW/watt)

where dBm = Power in dB referenced to 1 milliwatt

P = Power in watts

• If power level is 1 milliwatt:

Power(dBm) = 10 log (0.001 watt) (1000 mW/watt)

= 10 log (1)

= 10 (0) = 0



• Thus a power level of 1 milliwatt is 0 dBm.

• If the power level is 1 watt

1 watt Power in dBm = 10 log (1 watt) (1000 mW/watt)

= 10 (3)

= 30

• dBm = 10 log (P) (1000 mW/watt)

• The dBm can also be negative value.

• If power level is 1 microwatt

Power in dBm = 10 log (1 x 10E-6 watt) (1000 mW/watt)

= -30 dBm

• Since the dBm has a defined reference it can be converted back to watts if desired.

• Since it is in logarithmic form it may also be conveniently combined with other dB terms.

dBv/m

• To convert field strength in dbv/m to received power in dBm with a 50 optimum terminal

impedance and effective length of a half wave dipole /

0dBu = 10 log[(10-6

)2(1000)(/)

2/(4*50)] dBm

At 850MHZ

0dBu = -132 dBm

39dBu = -93 dBm



PROPAGATION LOSSES

Reflection

• Occurs when a wave impinges upon a smooth surface.

• Dimensions of the surface are large relative to .

• Reflections occur from the surface of the earth and from buildings and walls.

Diffraction (Shadowing)

• Occurs when the path is blocked by an object with large dimensions relative to and sharp

irregularities (edges).

• Secondary “wavelets” propagate into the shadowed region.

• Diffraction gives rise to bending of waves around the obstacle.

Scattering

• Occurs when a wave impinges upon an object with dimensions on the order of or less, causing

the reflected energy to spread out or“scatter” in many directions.

• Small objects such as street lights, signs, & leaves cause scattering

MULTIPATH

• Multiple Waves Create “Multipath”

• Due to propagation mechanisms, multiple waves arrive at the receiver

• Sometimes this includes a direct Line-of-Sight (LOS) signal

Fig 25. Multipath



Multipath Propagation

• Multipath propagation causes large and rapid fluctuations in a signal

• These fluctuations are not the same as the propagation path loss.

Multipath causes three major things

• Rapid changes in signal strength over a short distance or time.

• Random frequency modulation due to Doppler Shifts on different multipath signals.

• Time dispersion caused by multipath delays

• These are called “fading effects

• Multipath propagation results in small-scale fading.

FADING

• The communication between the base station and mobile station in mobile systems is mostly

non-LOS.

• The LOS path between the transmitter and the receiver is affected by terrain and obstructed by

buildings and other objects.

• The mobile station is also moving in different directions at different speeds.

• The RF signal from the transmitter is scattered by reflection and diffraction and reaches the

receiver through many non-LOS paths.

• This non-LOS path causes long-term and short term fluctuations in the form of log-normal

fading and rayleigh and rician fading, which degrades the performance of the RF channel.

Fig 26 Fading Graph



LONG TERM FADING

• Terrain configuration & man made environment causes long-term fading.

• Due to various shadowing and terrain effects the signal level measured on a circle around base

station shows some random fluctuations around the mean value of received signal strength.

• The long-term fades in signal strength, r, caused by the terrain configuration and man made

environments form a log-normal distribution, i.e the mean received signal strength, r, varies log-

normally in dB if the signal strength is measured over a distance of at least 40.

• Experimentally it has been determined that the standard deviation, , of the mean received signal

strength, r, lies between 8 to 12 dB with the higher generally found in large urban areas.

RAYLEIGH FADING

• This phenomenon is due to multipath propagation of the signal.

• The Rayleigh fading is applicable to obstructed propagation paths.

• All the signals are NLOS signals and there is no dominant direct path.

• Signals from all paths have comparable signal strengths.

• The instantaneous received power seen by a moving antenna becomes a random variable

depending on the location of the antenna.

Fig 27 Rayleigh Fading



RICEAN FADING

• This phenomenon is due to multipath propagation of the signal.

• In this case there is a partially scattered field.

• One dominant signal.

• Others are weaker.

Fig 28 Ricean Fading

RF PLANNING PROCEDURES

PRELIMINARY WORK

Propagation tool setup

Set up the planning tool hardware. This includes the server and or clients which may be UNIX

based.

Setup the plotter and printer to be used.

Terrain, Clutter, Vector data acquisition and setup

Procure the terrain, clutter and vector data in the required resolution.

Setup these data on the planning tool.

Test to see if they are displayed properly and printed correctly on the plotter.

Setup site tracking database



This is done using Project management or site management databases.

This is the central database which is used by all relevant department, viz. RF, Site acquisition,

Power, Civil engineering etc, and avoids data mismatch.

Load master lease site locations in database

If predetermined friendly sites that can be used are available, then load this data into the site

database.

Marketing Analysis and GOS determination

Marketing analysis is mostly done by the customer.

Growth plan is provided which lists the projected subscriber growth in phases.

GOS is determined in agreement with the customer (generally the GOS is taken as 2%)

Based on the marketing analysis, GOS and number of carriers as inputs, the network design is

carried out.

Zoning Analysis

This involves studying the height restrictions for antenna heights in the design area.

Set Initial Link Budget

Link Budget Analysis is the process of analyzing all major gains and losses in the forward and

reverse link radio paths.

Inputs

Base station & mobile receiver sensitivity parameters

Antenna gain at the base station & mobile station.

Hardware losses(Cable, connector, combiners etc).

Target coverage

reliabilty.Fade margins.

Output

Maximum allowable path loss.

Initial cell radius calculation



Using link budget calculation, the maximum allowable path loss is calculated.

Using Okumura hata emprical formula, the initial cell radius can be calculated.

Initial cell count estimates

Once the cell radius is known, the area covered by one site can be easily calculated.

By dividing the total area to be covered by the area of each cell, a initial estimate of the number

of cells can be made.

INITIALSURVEY

Morphology Definition

Morphology describes the density and height of man made or natural obstructions.

Morphology is used to more accurately predict the path loss.

Some morphology area definitions are Urban, Suburban, rural, open etc.

Density also applies to morphology definitions like dense urban, light suburban, commercial etc.

This basically leads to a number of sub-area formation where the link budget will differ and

hence the cell radius and cell count will differ.

Morphology Drive Test

This drive test is done to prepare generic models for network design.

Drive test is done to characterize the propagation and fading effects.

The objective is to collect field data to optimize or adjust the prediction model for preliminary

simulations.

A test transmitter and a receiver is used for this purpose.

The received signals are typically sampled ( around 50 samples in 40 ).

Propagation Tool Adjustment

The data collected by drive testing is used to prepare generic models.

For a given network design there may be more than one model like dense-urban, urban,

suburban, rural, highway etc.

The predicted and measured signal strengths are compared and the model adjusted to produce

minimum error.

These models are then used for initial design of the network



INITIAL DESIGN

Complete Initial Cell Placement

Planning of cell sites sub-area depending on clutter type and traffic required.

Run Propagation Analysis

Using generic models prepared by drive testing & prop test, run predictions for each cell

depending on morphology type to predict the coverage in the given sub-areas.

Planning tool calculates the path loss and received signal strength using Co-ordinates of the site

location, Ground elevation above mean sea level, Antenna height above ground, Antenna

radiation pattern (vertical & horizontal) & antenna orientation, Power radiated from the antenna.

Reset Cell Placement( Ideal Sites)

According to the predictions change the cell placements to design the network for contigious

coverage and appropriate traffic.

System Coverage Maps

Prepare presentations as follows

Background on paper showing area MAP which include highways, main roads etc.

Phase 1 sites layout on transparency.

Phase 1 sites composite coverage prediction.

Phase 2 sites layout transparency.

Phase 2 composite coverage prediction on transparency.

If more phases follow the same procedure.

Design Review With The Client

Initial design review has to be carried out with the client so that he agrees to the basic design of

the network.

During design review, first put only the background map which is on paper. Then step by step

put the site layout and coverage prediction.

Display may show some coverage holes in phase 1 which should get solved in phase 2 .



SELECTION OF SITES

Prepare Initial Search Ring

Note the latitude and longitude from planning tool.

Get the address of the area from mapping software.

Release the search ring with details like radius of search ring, height of antenna etc.

Release search rings to project management

Visit friendly site locations

If there are friendly sites available that can be used (infrastructure sharing), then these sites are to

be given preference.

If these sites suite the design requirements, then visit these sites first.

Select Initial Anchor Sites

Initial anchor sites are the sites which are very important for the network buildup, Eg - Sites that

will also work as a BSC.

Enter Data In Propagation Tool

Enter the sites exact location in the planning tool.

Perform Propagation Analysis

Now since the site has been selected and the lat/lon of the actual site ( which will be different

from the designed site) is known, put this site in the planning tool and predict coverage.

Check to see that the coverage objectives are met as per prediction.

Reset / Review Search Rings

If the prediction shows a coverage hole ( as the actual site may be shifted from the designed site),

the surrounding search rings can be resetted and reviewed.

Candidate site Visit( Average 3 per ring)

For each proposed location, surveys should carried out and at least 3 suitable site candidates

identified.

Details of each candidate should be recorded on a copy of the Site Proposal Form for that site.

Details must include:

» Site name and option letter Site location (Lat./Long)

» Building Height



» Site address and contact number

» Height of surrounding clutter

» Details of potential coverage effecting obstructions or other comments(A, B, C,...)

Drive Test And Review Best Candidate

In order to verify that a candidate site, selected based on its predicted coverage area, is actually

covering all objective areas, drive test has to be performed.

Drive test also points to potential interference problems or handover problems for the site.

The test transmitter has to be placed at the selected location with all parameters that have been

determined based on simulations.

Drive test all major roads and critical areas like convention centers, major business areas, roads

etc.

Take a plot of the data and check for sufficient signal strength, sufficient overlaps and splashes(

least inteference to other cells).

Drive Test Integration

The data obtained from the drive test has to be loaded on the planning tool and overlapped with

the prediction. This gives a idea of how close the prediction and actual drive test data match.

If they do not match ( say 80 to 90 %) then for that site the model may need tuning.

Visit Site With All Disciplines( SA, Power, Civil etc )

A meeting at the selected site takes place in which all concerned departments like RF

Engineering, Site acquisition, Power, Civil Engineer, Civil contractor and the site owner is

present.

Any objections are taken care off at this point itself.

Select Equipment Type For Site

Select equipment for the cell depending on channel requirements

Selection of antenna type and accessories.

Locate Equipment On Site For Construction Drawing

Plan of the building ( if site located on the building) to be made showing equipment placement,

cable runs, battery backup placement and antenna mounting positions.

Antenna mounting positions to be shown separately and clearly.



Drawings to be checked and signed by the Planner, site acquisition, power planner and project

manager.

Perform Link Balance Calculations

Link balance calculation per cell to be done to balance the uplink and the downlink path.

Basically link balance calculation is the same as power budget calculation. The only difference is

that on a per cell basis the transmit power of the BTS may be increased or decreased depending

on the pathloss on uplink and downlink.

EMI Studies

Study of RF Radiation exposure to ensure that it is within limits and control of hazardous areas.

Data sheet to be prepared per cell signed by RF Planner and project manager to be submitted to

the appropriate authority.

Radio Frequency Plan/ PN Plan

Frequency planning has to be carried out on the planning tool based on required C/I and C/A and

interference probabilities.

System Interference Plots

C/I, C/A, Best server plots etc has to be plotted.

These plots have to be reviewed with the customer to get the frequency plan passed.

Final Coverage Plot

This presentation should be the same as design review presentation.

This plot is with exact locations of the site in the network.

Identification of coverage holes

Coverage holes can be identified from the plots and subsequent action can be taken(like putting a

new site) to solve the problem.



LINK BUDGET

Link Budget Analysis is the process of analyzing all major gains and losses in the forward and

reverse link radio paths.

Inputs

Base station & mobile receiver sensitivity parameters

Antenna gain at the base station & mobile station.

Hardware losses(Cable, connector, combiners etc).

Target coverage reliabilty.

Fade margins

Output

Maximum allowed path loss



LINK BUDGET FOR 1800MHz FREQUENCY

Terrain Type: Dense Urban Urban Sub Urban Rural

Uplink

MS power (dBm) 30 30 30 30

Base Station Height 18 21 24 30

MS antenna gain (dB) 0 0 0 0

Diversity gain (dB) 3 4.5 4.5 3

Antenna Gain (dBi) 17.5 17.5 17.5 17.5

Feeder + Jumper loss , (dB) 3 3 3 3

Sens BTS (dBm) -111 -111 -111 -111

Allowed Path loss UL 156.5 158 158 156.5

Downlink

BTS power (dBm) 43 43 43 43


Antenna Gain (dBi) 17.5 17.5 17.5 17.5

Sens. MS (dBm) -102 -102 -102 -102

Body Loss [dB] 2 2 2 2

Allowed Path loss DL 157.5 157.5 157.5 157.5

Area coverage probability: 0.95 0.95 0.95 0.9

Log Normal Fading Marg [dB] 12 10 7 6

Building/Car Penetration Loss [dB] 24 20 14 9

Interference margin [dB] 2 2 2 2

Rayleigh fading margin [dB] 1 1 1 1

Max Allowed Path loss: [dB] 117.5 125 134 138.5

A -parameter (1800 MHz) 154.5 153.8 153.8 146.2

Coverage Range [km]: 0.291 0.512 0.954 2.296

With Formula 0.291188 0.512263 0.954429 2.295660



LINK BUDGET FOR 900MHz FREQUENCY

Terrain Type: Dense Urban Urban

Sub Urban Rural

Uplink

MS power (dBm) 21 23 23 24

Base Station Height 18 21 24 30

MS antenna gain (dB) 0 0 0 0

Diversity gain (dB) 2 2 2 2

Antenna Gain (dBi) 17.5 17.5 17.5 17.5


Sens BTS (dBm) -111 -111 -111 -111

Allowed Path loss UL 146.5 148.5 148.5 149.5

Downlink

BTS power (dBm) 43 43 43 43


Antenna Gain (dBi) 17.5 17.5 17.5 17.5

Sens. MS (dBm) -102 -102 -102 -102

Body Loss [dB] 2 2 2 2

Allowed Path loss DL 157.5 157.5 157.5 157.5

Area coverage probability: 0.95 0.95 0.95 0.9

Log Normal Fading Marg [dB] 12 10 7 6

Building/Car Penetration Loss [dB] 24 20 14 9

Interference margin [dB] 2 2 2 2

Rayleigh fading margin [dB] 1 1 1 1

Max Allowed Path loss: [dB] 107.5 115.5 124.5 131.5

A -parameter (900 MHz) 153.8 153.8 153.8 146.2

Coverage Range [km]: 0.162 0.280 0.519 1.453

With Formula 0.162411 0.280122 0.518587 1.452728



RF PLANNING TOOLS USED

1. Mentum Planet 5.5

2. Map Info Professional

MENTUM PLANET

The network of today's wireless operator must evolve to offer advanced data services cost-effectively -

and stay one step ahead of the competition.

New technologies such as LTE, HSPA and WiMAX present new opportunities, but their

advanced features, their usage patterns and the need for a cleaner radio channel that can offer

improved system capacity drive the requirement for innovative RF planning and optimization

software.

Better network design practices are generating long-lasting benefits in terms of quality of service

and network capacity.

Mentum Planet is a wireless network planning & optimization software that offers the ability to

design better networks through quality engineering solutions for the networks of today and

tomorrow.

Mentum Planet 5 - the fifth generation of this software platform - was built to address the

complex requirements of wireless broadband technologies for operators, equipment vendors, and

consulting firms involved in the planning, operation, and optimization of wireless networks.

The Mentum Planet product family supports most of the commercially deployed wireless

standards, including GSM, GPRS, EDGE, WCDMA, HSPA, HSPA+, LTE (TDD and FDD),

Wi-Fi, WiMAX, cdma2000, EVDO, TDMA, FDMA, DVB-H, TETRA, P25 and generic

TDMA/FDMA systems using simulcast.



Step1 :-Initial view of Mentum Planet 5.5 (Fig. 29)

STEP 2(Fig 30):- Designate a folder to save the project



STEP 3(Fig 31):- Name the project

STEP 4(Fig 32):- Select the project technology (GSM)



STEP 5(Fig 33):-Choose default settings for each entitled technology

STEP 6(Fig 34):- Choose geodata files that covers all sites



STEP 7(Fig 35):- Choose the Co-ordinate system to be used

STEP8(Fig 36):- View of the Clutter Mam for Delhi Region



STEP 9(Fig 37):-Grid Legend for Delhi Regon Clutter



STEP 10(Fig 38):-Create a Propogation Model to be Used

STEP 11(Fig 39):-Specify the Okumura Hata Model Values



STEP 12(Fig 40):- Define the propagation Models Depending on different clutter

STEP 13(Fig 41):-Select “Place a site” Tool as shown



STEP 14(Fig 42):- Click on the desired location to place a site

STEP 15(Fig 43):- Edit the Site Properties (select the P- Model)



STEP 16(Fig 44):- Select “FDMA/TDMA Analysis” from NETWORK ANALYSIS

WIZARD

STEP 17(Fig 45):-Select Sectors for Analysis



STEP 18(Fig 46):- Input the “Best Sector Assumptions”

STEP 19(fig 47):-Input the Interfernce parameters



STEP 20(Fig 48):-Input “Coverage Parameters”

STEP 21(Fig 49):- Select the layers to be analysed



STEP 22 (Fig 50):-Click on Finish

STEP 23(Fig 51):- Prediction generator for sectors of a site



STEP 24(Fig 52):-Best Signal StrengthAnalyser in Progress

STEP 25(Fig 53):- Sites Placed



STEP 26(Fig54):- Prediction for a single site with grid legend

STEP 27(Fig 55):- Overall Predictions Showing BSSS



Statistics

Area Covered in Sq.Km.

Dense Urban Urban Sub Urban Village

-200 ~ -85 0 10.316049 6.8341 2.92535

-85 ~ -80 0.1815 23.3907242 8.1121999 2.59417486

-80 ~ -75 1.1065 39.0406 9.2772747 1.784025

-75 ~ -65 64.9478 132.4624481 19.922474 3.994875

-65 ~ 0 116.202047 122.8879699 14.93 8.620025

Outside range 0 9.9421 16.25455 10.2271957

Total Area 182.437847 338.0398912 75.330599 30.1456456

Area Covered in %

Dense Urban Urban Sub Urban Village

-200 ~ -85 0 3.051725334 9.0721435 9.70405492

-85 ~ -80 0.099485936 6.919515953 10.768798 8.60547124

-80 ~ -75 0.606507925 11.54911033 12.315414 5.91801889

-75 ~ -65 35.5999597 39.18544868 26.446722 13.2519139

-65 ~ 0 63.69404644 36.3530971 19.819303 28.5945941

Outside range 0 2.941102591 21.577619 33.9259469



No. Of Sites

Area sq. kms Coverage range(kms.) Area Sites

Dense Urban 182.43785 0.291 0.16481 1106.956

Urban 338.0411 0.512 0.510198 662.5688

Sub urban 86.065175 0.954 1.771313 48.58834

Rural 32.466025 2.296 10.25988 3.164366

Others 4437.087425 2.296 10.25988 432.4696

TOTAL 5076.097575 6.349 22.96609 2253.747

NEED OF ADVANCED SYSYTEM

• Need for universal standard (Universal Mobile Telecommunication System)

• Support for packet data services

– IP data in core network

– Wireless IP

• New services in mobile multimedia need faster data transmission and flexible utilization of the

spectrum

• FDMA and TDMA are not efficient enough

– TDMA wastes time resources

– FDMA wastes frequency resources

• CDMA can exploit the whole bandwidth constantly

• Wideband CDMA was selected for a radio access system for UMTS (1997)

(Actually the superiority of OFDM was not fully understood by then)

FREQUENCY ALLOCATION FOR UMTS

• Frequency plans of Europe, Japan and Korea are harmonized

• US plan is incompatible, the spectrum reserved for 3G elsewhere is currently used for the US 2G

standards

• IMT-2000 band in Europe:



• FDD 2x60MHz

Fig 56.

WCDMA BACKGROUND AND EVOLUTION

• First major milestone was Release ‘99, 12/99

– Full set of specifications by 3GPP

– Targeted mainly on access part of the network

• Release 4, 03/01

– Core network was extended

– markets jumped over Rel 4

• Release 5, 03/02

– High Speed Downlink Packet Access (HSDPA)

• Release 6, end of 04/beginning of 05

– High Speed Uplink Packet Access (HSUPA)

• Release 7, 06/07

– Continuous Packet connectivity (improvement for e.g. VoIP), advanced features for HSDPA

(MIMO, higher order modulation)



3GPPRELEASE CONCEPT

Fig 57 3GPP Relesae Concept

EVOLUTION OF MOBILE STANDARDS



Fig 58 Evolution of mobile Standars



CURRENT WCDMA MARKETS

• Graph of the technologies adopted by the wireless users worldwide:

• Over 3.5 billion wireless users worldwide

• GSM+WCDMA share currently over 88 % (www.umts-forum.org)

• CDMA share is decreasing every year

Fig 59. WCDMA Subscriber Graph

GSM (80.9%)

CDMA (12%)

WCDMA (4.6%)

iDEN (0.9%)

PDC (0.8%)

US TDMA (0.8%)

http://www.umts-forum.org/



• Over 200 million WCDMA subscribers globally (04/08)

– 10 % HSDPA/HSUPA users

• Number of subscribers is constantly increasing.

MULTIPLE ACCESS SCHEMES

Fig 60. Multiple Access Schemes

• Frequency Division Multiple Access (FDMA), different frequencies for different users

– example Nordic Mobile Terminal (NMT) systems

• Time Division Multiple Access (TDMA), same frequency but different timeslots for different

users,

– example Global System for Mobile Communication (GSM)

– GSM also uses FDMA

• Code Division Multiple Access (CDMA), same frequency and time but users are separated from

each other with orthogonal codes.



SPREAD SPECTRUM

• Means that the transmission bandwidth is much larger than the information bandwidth i.e.

transmitted signal is spread to a wider bandwidth

– Bandwidth is not dependent on the information signal

• Benefits

– More secure communication

– Reduces the impact of interference (and jamming) due to processing gain

• Classification

– Direct Sequence (spreading with pseudo noise (PN) sequence)

– Frequency hopping (rapidly changing frequency)

– Time Hopping (large frequency, short transmission bursts)

• Direct Sequence is currently commercially most viable

DIRECT SEQUENCE

• In direct sequence (DS) user bits are coded with unique binary sequence i.e. with

spreading/channelization code

– The bits of the channelization code are called chips

– Chip rate (W) is typically much higher than bit rate (R)

– Codes need to be in some respect orthogonal to each other (cocktail party effect)

• Length of a channelization code

– defines how many chips are used to spread a single information bit and thus determines the end

bit rate

– Shorter code equals to higher bit rate but better Signal to Interference and Noise Ratio (SINR) is

required

• Also the shorter the code, the fewer number of codes are available

– Different bit rates have different geographical areas covered based on the interference levels.

• Transmission (Tx) side with DS

– Information signal is multiplied with channelization code => spread signal

• Receiving (Rx) side with DS



– Spread signal is multiplied with channelization code

– Multiplied signal (spread signal x code) is then integrated (i.e. summed together)

• If the integration results in adequately high (or low) values, the signal is meant for the receiver.

Fig 61. Direct Sequence Timing Graph

PROCESSING GAIN AND SPREADING

• Spread spectrum systems reduce the effect of interference due to processing gain

• Processing gain is generally defined as follows:

– G[dB]=10*log10(W/R), where ’W’ is the chip rate and ’R’ is the user bit rate

• The number of users takes negative effect on the processing gain. The loss is defined as:

– Lp = 10*log10k, where ’k’ is the amount of users

• Processing gain when the processing loss is taken into account is

– Gtot=10*log10(W/kR)

• High bit rate means lower processing gain and higher power OR smaller coverage

• The processing gain is different for different services over 3G mobile network (voice, web

browsing, videophone) due to different bit rates



– Thus, the coverage area and capacity might be different for different services depending on the

radio network planning issues

• Processing gain is what gives CDMA systems the robustness against self-interference that is

necessary in order to reuse the available 5 MHz carrier frequency over geographically close

distances.

• Examples: Speech service with a bit rate of 12.2 kbps

– processing gain 10 log10(3.84e6/12.2e3) = 25 dB

– For speech service the required SINR is typically in the order of 5.0 dB, so the required

wideband signal-to-interference ratio (also called “carrier-to-interference ratio, C/I ) is therefore

“5.0 dB minus the processing” = -20.0 dB.

– In other words, the signal power can be 20 dB under the interference or thermal noise power, and

the WCDMA receiver can still detect the signal.

– Notice: in GSM, a good quality speech connection requires C/I = 9–12 dB.C

Fig 62. Spreading Graph



Fig 63. Spreading Graph

WCDMA SYSTEMS

• WCDMA is the most common radio interface for UMTS systems

• Wide bandwidth, 3.84 Mcps (Megachips per second)

– Maps to 5 MHz due to pulse shaping and small guard bands between the carriers

• Users share the same 5 MHz frequency band and time

– UL and DL have separate 5 MHz frequency bands

• High bit rates

– With Release ’99 theoretically 2 Mbps both UL and DL

– 384 kbps highest implemented

• Fast power control (PC)

=> Reduces the impact of channel fading and minimizes the interference

• Soft handover

– Improves coverage, decreases interference

• Robust and low complexity RAKE receiver

– Introduces multipath diversity



• Variable spreading factor

– Support for flexible bit rates

• Multiplexing of different services on a single physical connection

– Simultaneous support of services with different QoS requirements:

• real-time

– E.g. voice, video telephony

• streaming

– streaming video and audio

• interactive

– web-browsing

• background

– e-mail download

CODES IN WCDMA

• Channelization Codes (=short code)

– Codes from different branches of the code tree are orthogonal

– Length is dependent on the spreading factor

– Used for

• channel separation from the single source in downlink

• separation of data and control channels from each other in the uplink

– Same channelization codes in every cell / mobiles and therefore the additional scrambling code is

needed

• Scrambling codes (=long code)

– Very long (38400 chips = 10 ms =1 radio frame), many codes available

– Does not spread the signal

– Uplink: to separate different mobiles

– Downlink: to separate different cells

– The correlation between two codes (two mobiles/NodeBs) is not fully orthogonal.



3G ANALYSES

STRENGTH

Worldwide standard for accessing global telecommunication.

WEAKNESS

High cost as compared to their predecessor.

THREAT

Since 2G mobile is in market, squeezing the market competition.

OPPURTUNITY

Consumers replacing handsets with newer technology.



Some Parameters of WCDMA Physical Layer

Carrier Spacing 5 MHz (nominal)

Chip Rate 3.84 Mcps

Frame Length 10 ms (38400 chips)

No. of slots/frame 15

No. of chips/slot 2560 chips (Max. 2560 bits)

Uplink SF 4 to 256

Downlink SF 4 to 512

Channel Rate 7.5 Kbps to 960 Kbps

Spreading Operation

Spreading means increasing the signal bandwidth

• Strictly speaking, spreading includes two operations:

• Channelization (increases signal bandwidth) - using orthogonal

codes

• Scrambling (does not affect the signal bandwidth) - using pseudo noise

codes

Channelization

In the uplink, it can only separate the physical channels/services of one

user because the mobiles are not synchronized in time.

• It is possible that two mobiles are using the same codes.

• In order to separate different users in the uplink, scrambling codes are

used.

• The channelization codes are picked from the code tree as shown in

next slide.

• One code tree is used with one scrambling code on top of the tree.

• If c4,4 is used, no codes from its subtree can be used (c8,7 , c8,8 , …).



SCRAMBLING

In the scrambling process the code sequence is multiplied with a

pseudorandom scrambling code.

• The scrambling code can be a long code (a Gold code with 10 ms

period) or a short code (S(2) code).

• In the downlink scrambling codes are used to reduce the inter-base station

interference. Typically, each Node B has only one scrambling

code for UEs to separate base stations. Since a code tree under one

scrambling code is used by all users in its cell, proper code

management is needed.

• In the uplink scrambling codes are used to separate the terminals.

Three separate channels concepts in the UTRA: logical, transport, and

physical channels.

• Logical channels define what type of data is transferred.

• Transport channels define how and with which type of characteristics the

data is transferred by the physical layer.

• Physical data define the exact physical characteristics of the radio channel.



Channel Concepts

Three separate channels concepts in the UTRA: logical, transport, and

physical channels.

• Logical channels define what type of data is transferred.

• Transport channels define how and with which type of characteristics the

data is transferred by the physical layer.

• Physical data define the exact physical characteristics of the radio channel.

Transport Channels -> Physical Channels

Transport channels contain the data generated at the higher layers,

which is carried over the air and are mapped in the physical layer to

different physical channels.

• The data is sent by transport block from MAC layer to physical layer

and generated by MAC layer every 10 ms.

• The transport format of each transport channel is identified by the

Transport Format Indicator (TFI), which is used in the interlayer

communication between the MAC layer and physical layer.

• Several transport channels can be multiplexed together by physical

layer to form a single Coded Composite Transport Channel

The physical layer combines several TFI information into the

Transport Format Combination Indicator (TFCI), which indicate

which transport channels are active for the current frame.

• Two types of transport channels: dedicated channels and common



channels.

• Dedicated channel –reserved for a single user only.

• Support fast power control and soft handover.

• Common channel – can be used by any user at any time.

• Don’t support soft handover but some support fast power control.

• In addition to the physical channels mapped from the transport

channels, there exist physical channels for signaling purposes to

carry only information between network and the terminals.

UL Dedicated Channel DCH

Due to audible interference to the audio equipment caused from the

discontinuous UL transmission, two dedicated physical channels are

I-Q/code multiplexing (called dual-channel QPSK modulation)

instead of time multiplexing.



Dedicated Physical Control Channel (DPCCH) has a fixed spreading factor

of 256 and carries physical layer control information.

• DPCCH has four fields: Pilot, TFCI, FBI, TPC.

Pilot – channel estimation + SIR estimate for PC

TFCI – bit rate, channel decoding, interleaving parameters for every

DPDCH frame

FBI (Feedback Information) – transmission diversity in the DL

TPC (Transmission Power Control) – power control command

•Dedicated Physical Data Channel (DPDCH) has a spreading factor

from 4 to 256 and its data rate may vary on a frame-by-frame basis.

•Parallel channel codes can be used in order to provide 2 Mbps user

data



UL Multiplexing and Channel Coding Chain



DL Dedicated Channel DCH

In the DL no audible interference is generated with DTX because the

common channels are continuously transmitting.

• Downlink DCH is transmitted on the Downlink Dedicated Physical

Channel (Downlink DPCH); thus, DPCCH and DPDCH are timemultiplexed

and using normal QPSK modulation.

A code tree under one scrambling code is shared by several users. Normally,

one scrambling code and thus only one code tree is used per sector in the BS.

• DCH SF does not vary on a frame-by-frame basis; thus, data rate is varied by

rate matching operation, puncturing or repeating bits, or with DTX, where the

transmission is off during part of the slot.

• The SF is the same for all the codes with multicode transmission.



UL DPDCH consists of BPSK symbols whereas DL DPDCH consists of QPSK

symbols. The bit rate in the DL DPDCH can be almost double that in the UL

DPDCH.

DL Multiplexing and Channel Coding Chain



Downlink Shared Channel (DSCH)

Used for dedicated control or traffic data (bursty traffic).

• Shared by several users. Each user may allocate a DSCH for a short

period of time based on a particular packet scheduling algorithm.

• Support the use of fast power control, but not soft-handover.

• Use a variable spreading factor on a frame-by-frame basis so that bit

rate can be varied on a frame-by-frame basis.

• Associated with a DL DPCH with the use of DPCCH. Such a DL

DPCCH from TFCI provides the power control information, an

indication to which terminal to decode the DSCH and spreading

code of the DSCH.

• Since the information of DSCH is provided from an associated DL

DPCH, the PDSCH frame may not be started before 3 slots after the

end of that associated DL DPCH.

Random Access Channel (RACH)

A contention-based uplink transport channel; thus, no scheduling is

performed.

• Use of RACH

• Carry control information from the UE to set up an initial

connection. For example, to register the UE after power-on to the

network or to perform location update or to initiate a call.

• Send small amount of packet data to network for 1 to 2 frames.

• Since it is needed to be heard from the whole cell for signaling

purposes, the data rate is quite low.

• No power control is supported.

RACH Operation

First, UE sends a preamble.

• The SF of the preamble is 256 and contain a signature sequence of 16

symbols – a total length of 4096 chips.

• Wait for the acknowledged with the Acquisition (AICH) from the BS.



• In case no AICH received after a period of time, the UE sends another

preamble with higher power.

• When AICH is received, UE sends 10 or 20 ms message part.

• The SF for the message is from 32 to 256.

Common Packet Channel (CPCH)

A contention-based uplink transport channel for transmission of

bursty data traffic.

• Different from RACH, channel can be reserved for several frames

and it uses fast power control.

• Information of CPCH is provided by

• DL DPCCH for fast power control information.

• Forward Access Channel (FACH) for higher layer DL signaling.

• CPCH operation is similar to RACH operation except that it has

Layer 1 Collision Detection (CD).

• In RACH, one RACH message is lost, whereas in CPCH an

undetected collision may lose several frames and cause extra

interference.

CPCH Operation

After receiving CPCH AICH,

• UE sends a CPCH CD preamble with the same power from another

signature.

• If no collision after a certain time, the BS echo this signature back to the

UE on the CD Indication Channel (CD-ICH).

• Then, the UE sends data over several frames with fast power control.

• The CPCH status indicator channel (CSICH) carries the status of different

CPCH information.



Broadcast Channel (BCH)

Downlink common transport channel.

• The physical channel of BCH is Primary Common Control Physical

Channel (Primary CCPCH).

• BCH:broadcast the system and cell-specific information, e.g., random

access codes or slots.

• Terminals must decode the broadcast channel to register to the cell.

• uses high power in order to reach all users within a cell.

Forward Access Channel (FACH)

Downlink common transport channel.

• It can be multiplexed with PCH to the same physical channel,

Secondary CCPCH, or standalone.

• FACH:

• carry control information to UEs within a cell.

• carry small amount of packet data.

• no power control.

• can have several FACHs. But the primary one must have low data

rate in order to be received by all terminals.

• In-band signaling is needed to inform for which user the data was

intended.



Paging Channel (PCH)

Downlink common transport channel for transmission of paging and

notification messages, i.e., when the network wants to initiate

communication with the terminal.

• It can be multiplexed with FACH to the same physical channel,

Secondary CCPCH, or standalone.

• The identical paging message can be sent in a single cell or hundreds

of cells. The paging message has to be reached by all the terminals

within the whole cell.

• Its transmission is associated with transmission of paging indicator in

paging indicator channel (PICH).

Signaling Physical Channels

Common Pilot Channel (CPICH)

Downlink channel with a fixed rate of 30 Kbps or SF of 256.

• Scrambled with the cell-specific primary scrambling code.

• Use for channel estimation reference at the terminal.

• Two types: primary and secondary CPICH

• Primary CPICH

• the measurements for the handover and cell selection / reselection.

• phase reference for SCH, primary CCPCH, AICH and etc.

• Secondary CPICH may be phase reference for the secondary

CCPCH.

Synchronisation Channel (SCH) – Cell Searching

SCH is used for cell search.

• Two subchannels: primary and secondary SCH.

• P-SCH and S-SCH are only sent during the first 256 chips of each

slot in parallel and time-multiplexed with the Primary CCPCH



Cell search using SCH has three basic steps:

• The UE searches the 256-chip primary synchronisation code,

which is common to all cells and is the same in every slot. Detect

peaks in the output of the filter corresponds to the slot boundary

(slot synchronisation).

• The UE seeks the largest peak secondary synchronisation code

(SSC). There are 64 unique SSC sequences. Each SSC sequence

has 15 SSCs. The UE needs to know 15 successive SSCs from the

S-SCH, then it can determine the code group in order to know the

frame boundary (frame synchronisation).

• Each code group has 8 primary scrambling. The correct one is

found by each possible scrambling code in turn over the CPICH

of that cell.

Synchronisation Channel (SCH) – Cell Searching

Cell search using SCH has three basic steps:

• The UE searches the 256-chip primary synchronisation code,

which is common to all cells and is the same in every slot. Detect

peaks in the output of the filter corresponds to the slot boundary

(slot synchronisation).

• The UE seeks the largest peak secondary synchronisation code

(SSC). There are 64 unique SSC sequences. Each SSC sequence

has 15 SSCs. The UE needs to know 15 successive SSCs from the

S-SCH, then it can determine the code group in order to know the

frame boundary (frame synchronisation).

• Each code group has 8 primary scrambling. The correct one is

found by each possible scrambling code in turn over the CPICH

of that cell.



Primary Common Control Physical Channel (Primary CCPCH)

Carries broadcast channel (BCH).

• Needs to be demodulated by all terminals within the cell.

• Fixed rate of 30 kbps with a spreading factor of 256.

• Contains no power control information.

• Primary CCPCH is time-multiplexed with SCH; thus, it does not use

the first 256 chips. Channel bit rate is reduced to 27 kbps.

Secondary Common Control Physical Channel (Secondary CCPCH)

Carries two transport channels: FACH and PCH, which can be

mapped to the same or separate channels.

• Variable bit rate.

• Fixed spreading factor is used. Data rate may vary with DTX or rate

matching parameters.

• Contains no power control information.

Power Control Procedure



Power Control (PC)

Fast Closed Loop PC – Inner Loop PC

• Feedback information.

• Uplink PC is used for near-far problem. Downlink PC is to ensure

that there is enough power for mobiles at the cell edge

.

• One PC command per slot – 1500 Hz

• Step 1 dB or 0.5 dB (1 PC command in every two slots).

• The SIR target for fast closed loop PC is set by the outer loop PC.

• Two special cases for fast closed loop PC:

• Soft handover: how to react to multiple power control commands

from several sources. At the mobile, a “power down” command

has higher priority over “power up” command.

• Compressed mode: Large step size is used after a compressed

frame to allow the power level to converge more quickly to the

correct value after the break.

Closed Loop PC - Outer Loop PC

• Set the SIR target in order to maintain a certain frame error rate

(FER). Operated at radio network controller (RNC).

• Open loop PC

• No feedback information.

• Make a rough estimate of the path loss by means of a downlink

beacon signal.

• Provide a coarse initial power setting of the mobile at the

beginning of a connection.

• Apply only prior to initiating the transmission on RACH or CPCH.



Transmit Diversity (BS)

Antenna diversity means that the same signal is transmitted or

received via more than one antenna.

• It can create multipath diversity against fading and shadowing.

• Transmit diversity at the BS - open-loop and closed-loop.

• Open Loop Mode

• No feedback information from the UE to the BS.

• BS decides the appropriate parameters for the TX diversity.

• Normally use for common channels because feedback

information from a particular UE may not be good for others

using the same common channel.

• Uses space-time-block-coding-based transmit diversity (STTD).

Closed Loop Mode

• Feedback information from the UE to the BS to optimize the

transmission from the diversity antenna.

• Normally use for dedicated channels because they have the

feedback information bits (FBI).

• Based on FBI, the BS can adjust the phase and/or amplitude of

the antennas.

Handover

Intra-mode handover

• Include soft handover, softer handover and hard handover.

• Rely on the Ec/No measurement performed from the CPICH.

• Inter-mode handover

• Handover to the UTRA TDD mode.



• Inter-system handover

• Handover to other system, such as GSM.

• Make measurement on the frequency during compressed mode.

PLANNING OF 3G SITES IN PATNA CIRCLE USUNG

MENTUM PLANET 5.5

STEP:1



STEP:2

STEP:3



STEP:4

STEP:5



STEP:6

STEP:7



STEP:8

STEP:9



STEP:10

STEP:11



STEP:12

STEP:13



STEP:14

STEP:15



STEP:16

STEP:17



STEP:18

STEP:19



STEP:20

STEP:21



REFERENCES

I. 3G Basics

II. gsmadvanced_aircomm

III. John.Wiley.and.Sons.WCDMA.for.UMTS.Radio.Access.for.Third.Generation.Mobile.Communi

cations

IV. WCDMA_systems_003

V. GSM Systra

VI. WIKIPEDIA

VII. www.umts-forum.org

http://www.umts-forum.org/

2g n 3g planning doc

Education

3g aircel

rf link design

prepare generic

company bought

base station

base transceiver

antenna mounting

base station