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Agenda

MAP INFO TOOL BSC PARAMETER & BSC CAPACITY FREQ PLANNING HOPPING SWITCH PARAMETER NEIGHBOUR PLANNING E1 STRUCTURE & TRAFFIC MAPPING

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Site Planning Tool

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Tool View Map info

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Tools Used

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MIPT Tool

OPEN FILE

SECTER SIZE

IMPORT MIPT

CREATE SITE

SEARCH SITE SEARCH FREQ

PLOT SITE

CLEAR COSMATIC LAYER

EDIT NEIGHBOUR DATABASE

SEARCH NEIGHBOUR

TOOLS REQ FOR DT

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Main Tool

POINTER ARROWGROUP SELECTION

ZOOM IN ZOOM OUT

GRABBER

INFO

LAYER CONTROLSCALE

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Drawing Tool

SYMBOL LINE

ARCPOLYLINE

TEXT

SHAPE ICON

STYLE ICON

Normally activated in cosmetic layer.

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Type Of Sites

New town Infill IBS (In Building Solutions) Combined Indoor & Outdoor sites NOW (Network on wheel) Highway Coverage Railway coverage

Showcase Sites Non- showcase Sites

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BSC Parameter BCF (Base Control Function):-

One BCF = one site of three or four sector One BSC= 1 to 248 BCF Ex- one site of 2+2+2 config (6 TRX) One BSC= 6 BCSU ( Base control signaling unit) One BCSU= 110, 200TRX One BSC= 660 TRX , 1000 TRX Etc.. Normally 110 or 166 sites can create in one BSC so One BSC

= 1 to 248 BCF. BCF Id Range= 1 to 660( with this parameter we identify BCF

with a decimal number). With the help of ND111 report we can plan BCF id for new site

planning.

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BTS ( Base Transreciever system)

One BSC (Base station controller) = 1 to 248 BTS One BTS = one sector of any configuration Main BTS Types are

Flexi = Max 24 TRX (cabinet=12, stack mount=24) Ultra = Max 12 TRX Metro = Max 4 TRX

BTS Id Range= 1 to 660 BTS ID= With this parameter we identify the BTS. The identification number must be unique within a BSC. With the help of ND111 report we can plan BTS id for new site

planning.

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LAC (Location Area Code)

One BSC = One or two LAC (mostly one)

One LAC = 367 sites of 2+2+2 configuration

One LAC = 266 sites of 4+4+4 configuration

One LAC = 10, 000 subscriber

One LAC = 100000 Erlangs

Lac range= 0 to 65535

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Objectives of LACBy dividing a PLMN area into various location area paging load is

reduced. This is due to the fact that whenever there is a page for a mobile, it is sent by the MSC to those BSCs which have cells with location area codes same as that of the current location area code of the mobile. If the entire PLMN area has been defined as a single location area then the MSC has to page for each and every mobile in every BSC which increases paging load thereby increasing the signalling load resulting in wastage of resources. Thus the Mobile Station is typically paged only in the cells grouped under one Location Area Code when an incoming call arrives.

The foremost objective is to minimize resource consumption, taking into account the signaling load on the radio path both from paging and from location updates as well as the processing load of the equipment.

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NSEI (Network service entity identifier)

NSEI is hardware device which supports the GPRS( General package radio service) in network.

one NSEI supports 64 BTS and 128 TRX (depends on DAP slot). If any one of them is full then we can assign second NSEI port in same BSC.

With this parameter we define the network service entity identifiers of the routing area. The maximum number of network service entities in a routing area is 16.

NSEI= Network code+ BSC Id + Port no Ex:- 21031 here 2 is unique network code, 103 is BSC & 1 is nsei port 1.With the help of 51 report & neighbouring site we can plan NSEI for

new site.NSEI Range= 0 to 65535

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RAC (Routing Area Code)

This parameter specifies that the network service (NS) in the GPRS. Packet service state performs location management based on the routing area. Each routing area has an ID. The routing area ID is broadcast in the system message.

RAC is basically related to GPRS With this parameter we identify GPRS cells using the

routing area code number. BSC id= RAC (for airtel) Ex:- BSC01WKP

Then, RAC= 01 RAC Range = 0 to 255

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Frequency Planning BCCH (broadcast control channel) Freq

BCCH freq band is distributed district wise. We need to consider BCCH freq band for planning Freq

in any district. TCH ( traffic channel) freq is also distributed & we need to

consider TCH freq band district wise before MAL (mobile allocation list) Planning.

Before starting freq planning we need to Confirm the BSC, Check the utilization of nearby existing site & clutter & Cross verify the required TRX (Transreceiver) config.

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BCCH & TCH Freq Band For Nashik District

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BCCH & TCH Freq Band For Pune & Thane District

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BCCH & TCH Freq Band

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BSC boundry

Raigad

Satara

Ratnagiri

District boundry

Satara & Ratnagiri use different BCCH & TCH band freq.

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Freq Planning Procedure Check district boundary of site, consider Freq band of concern

District boundary.

Search appropriate freq with the use of MapInfo tool.

Check 232 reports for the coverage of existing sites.

Check the Logs.

Take side lobe & back lobe into consideration while freq planning.

Plan freq such that interference won’t take place.

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232- Report

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Logs

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BSIC Planning BSIC (base station identification code)

BSIC= NCC( network colour code) + BCC ( BTS colour code) NCC= Varies from 0 to 7. (0 or 5 for airtel) BCC= varies from 0 to 7 (for airtel) So Bsic varies from 00 to 07 & 50 to 57. Search appropriate NCC & BCC with the use of MapInfo tool. Plan bcch & bsic in such a way that Co-channel & Co-bsic

interference should not be there.

NCC BCC

BSIC

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BCC- Base Station Colour Code

This parameter specifies the base station color code.

The BCC identifies the cells with the same BCCH frequency in the neighborhood.

According to GSM protocols, the TSC (Training Sequence Code) and BCC of a BCCH must be the same.

If co-channel interference occurs, different TSC (the same as BCC) training sequences on TCHs are used to differentiate between interference signals and normal speech signals. Therefore, appropriate planning of the BCC can reduce the impact of interference on speech signals.

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TSC- Training Sequence Code The TSC must be the same as the BCC.

TSC= varies from 0 to 7

The delay equalization is performed by using the specified TSC when the MS or BTS receives the signal. The demodulation cannot be received because the delay equalization cannot be performed for the signals with same frequency using different TSCs. This can effectively prevent incorrectly invalid reception, and prevent the co-channel interference.

In signal processing, delay equalization corresponds to adjusting the relative phases of different frequencies to achieve a constant group delay.

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NCC- Network Colour Code

This parameter specifies the network color code, which is provided by the telecom operator.

The NCC is used to identify networks from area to area.

NCC is unique nationwide.

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What Is What Is INTERFERNCE ?INTERFERNCE ?

Interference is the sum of all signal contributions that are neither noise not the wanted signal.

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Effects Of InterferenceEffects Of Interference Interference is a major limiting factor in the performance of

cellular systems.

It causes degradation of signal quality.

TYPE OF INTERFERNCETYPE OF INTERFERNCE

There are two types of system generated interference

Co-channel interference

Adjacent channel interference

Co- channel & Co-Bsic interference

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Co-Channel Interference This type of interference is the due to frequency reuse , i.e.

several cells use the same set of frequency. These cells are called co-channel cells. Co-channel interference cannot be combated by increasing

the power of the transmitter. This is because an increase in carrier transmit power increases the interference to neighboring co-channel cells.

To reduce co-channel interference, co-channel cells must be physically separated by a minimum distance to provide sufficient isolation due to propagation or reduce the footprint of the cell.

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Co-Channel

611

611

Co- Channel interference

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Co-channel, Co-Bsic

545, bsic=56

545, bsic=56

Co- Channel, Co-bsic interference

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Adjacent-Channel Interference

Interference resulting from signals which are adjacent in frequency to the desired signal is called adjacent channel interference.

Adjacent channel interference results from imperfect receiver filters which allow nearby frequencies to leak into the pass band.

Adjacent channel interference can be minimized through careful filtering and channel assignments.

By keeping the frequency separation between each channel in a given cell as large as possible , the adjacent interference may be reduced considerably.

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Frequency Hopping Process of continuously changing frequency is known as

Frequency Hopping

Freq hopping is principal component of the variable interference planning solution offered by Lucent technologies, & is supported in both GSM 900 & GSM 1800 networks.

Freq hopping increases the probability that all calls will have acceptable quality rather than some having very good quality & other having unacceptable quality

Call is transmitted through several frequencies in order to average the interference minimize the impact of fading

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Type Of Hopping Base Band Hopping

Fixed length( freq) Mal (No of frequency = No of TRX) Uses two HSN( hopping sequence number), HSN1

used for non BCCH TRX and HSN2 used for all TRX including BCCH.

RF or Synthesizer Hopping

Only HSN1 is used BCCH TRX does not hope Up to 64 frequency can hope

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BB Hopping ManagementBB Hopping

Management

BCCH 0 0 0 000

0 1 1 1 111

1 2 2 2 222

2 3 3 3 333

TRX-1

TRX-2

TRX-3

TRX-4

RTSL-0 RTSL-2RTSL-1 RTSL-4RTSL-3 RTSL-5 RTSL-6 RTSL-7

f1

f2

f3

f4

BCCH timeslot, does not hop.BCCH timeslot, does not hop.

0

1

3

2

Timeslot 0 of TRXs 2-4 hop over MA(f2,f3,f4).This hopping group uses HSN-1

Timeslot 0 of TRXs 2-4 hop over MA(f2,f3,f4).This hopping group uses HSN-1

All timeslots 1-7 hop over MA(f1,f2,f3,f4).This hopping group uses HSN-2

All timeslots 1-7 hop over MA(f1,f2,f3,f4).This hopping group uses HSN-2

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RF Hopping ManagementRF Hopping

Management

BCCH 0 0 0 000

0 0 0 0 000

1 1 1 1 111

2 2 2 2 222

TRX-1

TRX-2

TRX-3

TRX-4

RTSL-0 RTSL-2RTSL-1 RTSL-4RTSL-3 RTSL-5 RTSL-6 RTSL-7

MA = {f1}

BCCH TRX, does not hop.BCCH TRX, does not hop.

0

0

2

1

MAIOs have tobe different for different TRXswithin the samehopping group-> no collisions.

MAIOs have tobe different for different TRXswithin the samehopping group-> no collisions.

MA = {f2, f3, f4,..}

HSN-1 HSN-1

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Hopping Planning HSN (Hopping Sequence Number)

The order in which the mobile station should change the freq is called the “freq hopping sequence”.

HSN defines a number that fed into freq hopping algo to generate freq hopping sequence.

Values can be 0 to 63. Value 0 can define cyclic hopping (fixed rotation of freq) & 1-63

generates a pseudo random sequence (random rotation of freq) Normally we use HSN 1-63 for airtel. If a particular site has more than 2 E1, ie such as having 6+6+6

then cells are not synchronized to each other. Only cells that share same bcf id are synchronized and can share same HSN.

Non synchronized cells must be allocated different HSN. Plan the HSN with reference to ND111 & existing sites.

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Random vs Cyclic Hopping Sequences Where To Use?

Cyclic:

In the areas where the interference is NOT a problem (low traffic areas)

Random:

In the areas where the interference is a problem (high traffic areas)

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MAL (Mobile Allocation freq List) Contains the list of freq. With this parameter we define the mobile allocation frequency

list to which the BTS will be attached.

MAIO (Mobile Allocation Index Offset) Defines the starting freq from where transmission will start o

within a hopping sequence. With MAIO offset it is possible to use the same MA frequency

list for two or more sectors of the site without collisions. Value can be 0 to N-1, where N= no. of hopping freq.

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MS (MAIO Step)

Indicate the index of freq from where freq hopping will start for 2nd TRX & onwards.

For Mal planning we use ZEBI dump. Mal freq are adjusted as per the TCH band define in that particular district.

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ZEBI Dump

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Switch Parameter

MSC (MOBILE SWITCHING CENTRE)

We need to define the concern MSC for the BSC in which we are planning new site from MSC Dump.

CLN ( Location number of cell)

Take the neighboring site of same BSC & check the CLN of that site in given MSC dump. Define same CLN for our site.

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BSC-MSC List

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MSC Dump

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Neighbour Definition Neighbour definition is basically for the handover purpose.

For proper neighbour planning we need to consider following

Logs (Clutter)site orientation of new siteArea populationCoverage capacity of existing sitesRoad & railways Antenna height of new site Type of site (new town, Infill, IBS)

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Number Of Neighbours In one SACCH multiframe there are 104 TDMA frames. Out of this 104 frames 4 frames are idle and are used to

decode the BSIC. Remaining 100 TDMA frames are used to measure

RSS( Received Signal Strength) of the neighbour. If 25 neighbours are equipped, then in one SACCH multiframe

each neighbour is measured 100/25 = 4 times and averaged out. This produces a less accurate value.

If 10 neighbors are equipped, then in one SACCH multiframe each neighbor is measured 100/10 = 10 times and averaged out. This produces a more accurate value.

If high numbers of neighbours are equipped, then the accuracy of RSS is decreased as should have 8 to 10 neighbours.

Maximum 32 averaging of RSS takes place. So Minimum 3 neighbour should be defined to one cell.

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Neighbour Planning In Road & Railway Cases.

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Neighbour planning with clutter cases.

AMSL=39M

AMSL=45M

Clutter AMSL= 254M

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Handover Handover is a GSM feature by which the

control/communication of a Mobile is transferred from one cell to another if certain criteria’s are met. It is a network initiated process.

Handover ensures that the connection to the mobile station is maintain as it moves from on BSS (Base station subsystem) area to another.

What is the purpose of HO?Call continuityCall qualityTraffic sharing

Handover process may be triggered by Quality, field strength or distance values fall below/exceed their threshold

BSC or MSC takes the decision for handover depends on the type of handover

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Types Of Handover Intra MSC handover:-

Handover between the base stations connected to the same MSC, is termed as Intra MSC handover.

Intra cell - Intra BSC handover Inter cell - Intra BSC handover Inter cell – Inter BSC handover

Inter MSC handover:-

Handover between the base stations connected to the different MSC, is termed as Inter MSC handover.

This also a part of external handover process.

INTERNAL HANDOVER

EXTERNAL HANDOVER

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INTRA MSC Handover

BASIC EXTERNAL INTRA MSC HANDOVER

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BSS-A sends handover require msg to MSC. MSC Send handover request msg to BSS-B(BSS-A & BSS-B are

same in case of intra cell-intra BSC & Inter Cell- Intra BSC handover)

BSS-B allocates radio resource for MS & send HO request acknowlgement.

Then MSC instruct BSS-A to tune to new radio resource by sending handover command to BSS-A.

Now MS access new radio resource then BSS-B ensures that expected MS has been captured or not.

If MS get verified, BSS-B send an handover detect msg to MSC. When MS successfully communicating with BSS-B then HO

complete msg will get send by MS to BSS-B. After this resources allocated to BSS-A get released by using the

Clear command.

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Intra cell - Intra BSC handover

The smallest of the handovers is the intra cell handover where the subscriber is handed over to another traffic channel (generally in another frequency) within the same cell.

In this case the BSC controlling the cell makes the decision to perform handover without any intimation to the MSC.

Inter cell - Intra BSC handover

In this case subscriber moves from cell 1 to cell 2 Handover process is controlled by BSC and inform MSC about

the same. The traffic connection with cell 1 is released when the

connection with cell 2 is set up successfully

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Inter cell - Inter BSC handover

In this case subscriber moves from cell 2 to cell 3, which is served by another BSC.

Handover process is carried out by the MSC, but, the decision to make the handover is still done by the first BSC.

Connection with the first BSC (and BTS) is released when the connection with the new BSC (and BTS) is set up successfully.

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Inter MSC Handover

BASIC EXTERNAL INTER MSC HANDOVER

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BSS-A sends handover require msg to MSC-A. MSC-A generates handover request msg to MSC-B & MSC-B forwards

this request to BSS-B. BSS-B allocates radio resource for MS & send HO request

acknowlgement. MSC-B now provides this HO response to MSC-A. Then MSC-A instruct BSS-A to tune to new radio resource by sending

handover command to BSS-A. Now MS access new radio resource then BSS-B ensures that expected

MS has been captured or not. If MS get verified, BSS-B send an handover detect msg to MSC-B. MSC-B sends Access signal to ensure that expected & correct MS is

captured. When MS successfully communicating with BSS-B then HO complete

msg will get send by BSS-B to MSC-B. Now MSC-B sends end signal request. After this resources allocated to BSS-A get released by using the Clear

command.

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E1 Basics T-1 and E-1 are digital telephony schemes provided by communication

carriers that multiplex a number of digital voice channels onto a single, higher speed line.

T1 has 24 channels with data rate of 1.544 Mbps E1 has 32 channels with data rate of 2.048 Mbps. The T-1 or E-1 transmission path is bidirectional and transmits and

receives the digital information simultaneously. E-1 is a multiplexing scheme used primarily in Europe and Asia that

allows 30 individual voice channels to be carried on a common transmission medium.

By converting analog voice signals to digital signals using pulse coded modulation (PCM) and the multiplexing these signals onto a high speed digital line, 30 separate phone calls can be transmitted simultaneously over a single transmission path.

Framing given in 0th channel is necessary so any equipment receiving the E1 signal can synchronize identify, and extract the individual channels.

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E1 Structure 32 time slots in one E1. Each one is 64 Kbps. 32 x 64 Kbps = 2.048 Mbps. 0th slot is used for framing purpose. We divide each slot in four part (each

16 kbps). So one TRX needs 2 time slot. Each TRX and BTS needs its

signaling Bits generally mapped at the end.

For normal case we put TRX from 1 to 20th slot, from 21 to 26th slot is used for giving Edge i.e. EDAP Pool and 27 to 31 timeslot is used for TRX and BTS signaling.

Last 31st slot is used for BTS signaling and management purpose

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Traffic Mapping

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Example Of Traffic Mapping

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From the traffic plan we can show how the time slot mapping of E1 channel is done.

We can assign maximum 13 TRX to one E1 in normal mode. Here the traffic channel is allocated in time slot 1 and time slot

0 is given for link management i.e. frame synchronization. Number of TRX used here are 6 in 222 configuration in 3

sectors so the numbers given are 1,2,5,6,9 and 10 i.e. first 2 TRX of all the sectors.

Time slot 27 and 28 is used for signaling of TRX as each TRX requires its own signaling.

Time slot 31 used for BCF signaling, priority bits, MCB/LCB and Q1 management.

P1 indicates the priority for the site.

Details Of Traffic Mapping

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Example Of Traffic Mapping With EDAP

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Example of Traffic Mapping In Case Of Multi Drop

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