GSM RF Planning

Project Supervisor:

Mr.Qazi Zeeshan

Group Members:

Abdul-Raheem

Nargis Sultana

Cellular Communication

Communication between mobile subscribers..

It removes the fixed wiring

Mobile subscriber is able to move around, perhaps

can travel in a vehicle or on foot & still make &

receive call.

The Cell…..

The hexagonal-shaped communication cells are artificial & are generated to simplify the planning & design of a cellular network.

BTS

Fitting of the cellular structure

A

Cellular structure

Base Station

Base Station

Base Station

Base StationBase Station

Base Station

Each cell is served by a base station.

Coverage & Capacity

Cell Size

Large Cells

35 Km

Small Cells

Near about 1 KM

Urban Areas

GSM

one or more RF carriers in each cell. An RF carrier is a pair of radio frequencies

One used in upward direction by MS - Uplink Other used in downward direction by BTS - Downlink The transmit and receive frequencies are separated by a

gap of 45 MHz in GSM of 75 MHz in DCS. There are 124 carries in GSM Band. With each

carrier carrying 8 timeslots, only 124 x 8 = 992 calls can be made!

Frequency Reuse is the solution

Uplink-Downlink

Downlink = 935 to 960 MHz

Uplink = 890 to 915 MHz

BTS Tx MS Rx

BTS Rx MS Tx

dl

ul

Frequency Reuse Pattern

Three types of frequency reuse patterns

7 Cell reuse pattern

4 cell reuse pattern

3 cell reuse pattern

Cell Dia = R

FREQUENCY RE - USE

Frequency Re-use

7 cell cluster

1

2

3

45

6

7D D/R = (3N)1/2

where N is Cluster size

Principal Of Sectorization

Omni Directional Cells 120 degree Sectors 60 Degree sectors

Each Sector in a Site has its own allocation of Radio Carriers.

Advantage By frequent reuse of frequency more capacity can be

achieved.

a1a2

a3a3

a4a6

a5

Cell Sectorisation

OMNI CELL

1 ANTENNA

b1

b2

b3

120O CELLS

3 ANTENNAS

60O CELLS

6 ANTENNAS

3 Site Reuse Pattern

c2

c1

c3

a1

a2

a3

b1

b2

b3

c1c2

c3Cell Re-use

Continued…3 cluster site

3/9 cell cluster 4 cluster site 4/12 cell cluster

Base Station 2

Base Station 3

Base Station 1

Handovers

GSM NETWORK ELEMENTS

PSTNMSC

HLR

AUC

VLR

EIR

TRAU BSC

BTS

Network Switching System

BSS

SIM

ME

MS

GSM Network Components Mobile Station consists of two parts-

Mobile Equipment (ME)

Subscriber Identity Module (SIM)

ME

Hardware e.g. Telephone, Fax Machine,

Computer.

SIM

Smart Card which plugs into the ME.

Mobile Equipment (ME)

A handset

SIM

Subscriber Interface Identity Module

--------------

--------------

Small SIM

Full Size SIM Card

--------------

--------------

SIM stores…

IMSI (International Mobile

Subscriber Identity)Permanently stored on SIM card

15 digit Decimal

MCC (3) MNC (2) MSIN (10)

LAI (Location Area Identity)

MCC-3digit number MNC-2 digit number LAC-3 digit number CI-5digit number Temporary Mobile Subscriber Identity (TMSI)

Temporary number assigned to the subscriber by VLR .used locally. It is a 4 byte code.

LACMCC MNC CI

SIM continued…

MSISDN (Mobile subscriber ISDN) 10 digit number to which a subscriber is being called.

PIN (Personal Identification Number) Four digit PIN An internal security to Protect the SIM from illegal use. Card blocks itself after three wrong entries

PUK (Personal Unblocking Key) 8 digit code to unblock the SIM Card

Ki (Authentication Key), A3 & A8 Algorithms

Base Station System (BSS) BSS (Base Station System)

BSC (Base Site Controller) BTS (Base Transceiver Station) XCDR (Transcoder)

Network Switching System (NSS)

XCDR

BSC

BTS

Base Station System (BSS)

BSCControls upto 40 BTSConveys information to/from BTSControls handovers between BTSs

under itself BTS

1 - 6 carriers in a BTS7 - 48 simultaneous calls per BTS

Network Switching System(NSS)

NSS (Network Switching System)

MSC (Mobile Switching Centre)

HLR (Home Location Register)

VLR (Visitor Location Register)

EIR (Equipment Identity Register)

AUC (Authentication Centre)

o The OMC has access to the (G)MSC, BSC.o Handles error messages being reported from the Networko Controls the traffic load of the BSC, and the BTS.

Operation & Maintenance Centre

GSM Interfaces Um MS - BTS

Abis BTS - BSC

A BSC - MSC

B MSC - VLR

C MSC - HLR

D VLR - HLR

E MSC - MSC

F MSC - EIR

G VLR - VLR

H HLR - AUC

TDMA F

RAME n

+10 7

3

0

5

01

2

0 7

3

0

5

01

2

4.61

5 m

S

TDMA F

RAME n

T D M

A

TDMA & FDMA

F D M A200KHz

Uplink - MS Tx890MHz to 915MHz

Downlink - BTS Tx935MHz to 960MHz

LOGICAL CHANNELS

0 1 2 3 4 5 6 7

3

57 encrypted

57 encrypted

26 training

1S

1S

3T

8.25GP

3T

577S

577S x 8 = 4.615mS

TDMA Frame

Normal Burst

26 Frame Multi-frame

BURST

Five Types of Burst

Normal BurstTraffic & Control Channels

Frequency Correction Burst

FCCH

Synchronization Burst

SCH

Dummy Burst

BCCH Carrier

Access Burst

RACH

GSM Logical Channels

TCH and Control Channels

Frames & Multiframes

Traffic Channel occupy a 26-frame multiframe

(120 ms)

Control Channel occupy a 51-frame multiframe

(235 ms).

Channels On Air InterfaceBCCH

BCCH, FCCH, SCH

CCCH RACH, PCH, AGCH, DCCH

Channels On Air Interface

DCCH SDCCH

FACCH & SACCH

Call Scenarios Mobile to Mobile

Intra-city Inter-city

Mobile to Land Intra-city Inter-city

Land to Mobile Intra-city Inter-city

MULTI-PATH PROPAGATION

FREQUENCY HOPPING

F0

F2

F3

F4

FN

F1

T I M E

FR

EQ

UE

NC

Y

RF Planning Aspects

Coverage

Total sites used are 8.

S333,s22,and s332 site configuration is used.

3/9 Multiplexing mode used. i-e 3x3 frequency reuse.

The radio channel configuration model

Number of TRXs

in a cell Number of control

channels Number of voice channels

Capacity ? Erlang?

2% congestion rate

Capacity ? Erlang?

5% congestion rate

1 1? BCCH+SDCCH? 7 2.94 3.74 2 1BCCH+1SDCCH 14 8.2 9.73 3 1BCCH+1SDCCH 22 14.9 17.1 4 1BCCH+1SDCCH 30 22 24.8 5 1BCCH+2SDCCH 37 28 31.6 6 1BCCH+2SDCCH 45 35.5 39.6 7 1BCCH+2SDCCH 53 43 47.53

3x3 frequency re-use:

continued…

• Capacity:

Number of potential users = 12,000

Average BHCA = 2minutes

mean holding time per call = 45seconds

erlang per subscriber = (45*2)/3600 = 0.25erlang

Design capacity of a network :

10,000*0.025 = 250erlang

Frequency Planning softwares

Softwares used are:

ASSETT PLANET GAIA

FINAL PROJECT

GSM RF PLANNING

Project specifications

5MHz Frequency band used is:

uplink 1780-1785

downlink 1875-1880

Total RF carriers = 25 120degree antenna used

Coverage forecast table

B T S ID B T S N a m e C o n fig u ra t io n T O W N P R O V IN C E L O N L A T G N D H T A z im u t h H e ig h tA B D 0 0 1 S a rb a n C h o w k S 3 3 3 A b b o t t a b a d N W F P 7 3 . 2 2 0 2 3 4 . 1 4 8 2 1 2 3 7 1 4 0 3 5A B D 0 0 2 S u p p ly B a z a r S 3 3 2 A b b o t t a b a d N W F P 7 3 . 2 2 5 3 4 . 1 7 0 9 1 2 0 0 6 0 3 5A B D 0 0 3 S h im la P a h a r i S 3 3 3 A b b o t t a b a d N W F P 7 3 . 2 0 0 8 3 4 . 1 4 8 2 1 3 4 9 1 2 0 3 5A B D 0 0 4 N a w a n S h e h r S 3 3 3 A b b o t t a b a d N W F P 7 3 . 2 6 5 3 3 4 . 1 6 3 4 1 2 3 7 1 8 0 3 5A B D 0 0 5 K a k u l S 3 3 2 A b b o t t a b a d N W F P 7 3 . 2 4 7 9 3 4 . 1 8 2 6 1 2 2 3 9 0 3 5A B D 0 0 6 S I S t a t e S 3 3 3 A b b o t t a b a d N W F P 7 3 . 2 3 4 8 3 4 . 2 0 0 1 1 2 0 0 1 8 0 3 5A B D 0 0 7 S h a h ra h -e -R a is h a m S 2 2 A b b o t t a b a d N W F P 7 3 . 1 7 7 2 3 4 . 1 2 7 1 3 9 7 8 0 3 5A B D 0 0 8 C h in a r R o a d S 3 3 2 A b b o t t a b a d N W F P 7 3 . 2 3 6 5 3 4 . 1 5 9 4 1 2 0 0 1 8 0 3 5

mapped data

Coverage

Mean received power

Path Loss

END OF PRESENTATION

QUESTIONS???