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GSM Cellular
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RF PLANNING & MEASURING COVERAGE AREA USING DRIVE TOOL
GLOBALSYSTEM FOR MOBILE COMMUNICATION
BySK.ABDUL SATTAR (06J01A0403)
K.ALTAF (06J01A0415)FAHEEM NASER (06J01A0431)
AZHAR MOHAMMAD (06J01A0433)
MOBILE SPEED 2G GSM/CDMA =>(9.6 – 14.4)kbps 2.5G
GPRS – 115kbpsEDGE - 384kbpsCDMA – 170kbps
3GEVDOEVDV UMTSHASDPA – 14Mbps
WIRELESS INTERFACE CHALLENGES Low bandwidth Interference / Noise NLOS Environment Large Capacity Requirement Huge Demand
OBJECTIVES OF MOBILE COMMUNICATIONS Anytime Anywhere Mobility & Roaming High capacity & subs. density Seamless Network Architecture Low cost Flexibility Innovative Services Standard Interfaces Efficient use of radio spectrum
BANDWIDTH MANAGEMENT TECHNIQUES FDMA TDMA Cellular Technology & Frequency Re-use Scheme
Speech Coding Modulation
FDMA Frequency Division Multiple Access or
FDMA is a channel access method used in multiple-access protocols as a channelization protocol. FDMA gives users an individual allocation of one or several frequency bands, or channels
Uplink Frequency Band = (890 – 915) MHz Downlink Frequency Band = (935 – 960)
MHz Absolute Radio Freq Carrier Number
(ARFCN) Bandwidth = 915 – 890 or 960 – 935
= 25 MHz
Freq
Mhz. 890.2
1
890.4
2
890.6
3
890.8
4
891.0
5 6
914.8
124
• FDMA Access along Frequency axis• Each RF carrier 200khz apart
• Total 124 RF Channels available. One or more carrier assigned to each base station
……...
FDMA Access along Frequency axis
GSMFDMA
25 MHz 25 MHz
Mobile to Base
0 1 2
890.2 890.4 890.6(MHz)
Base to Mobile
0 1 2
935.2 935.4 935.6
200 kHz45MHz
Channel layout and frequency bands of operation
890 935 960915
200 kHz
TDMA
Time Division Multiple Access Scheme One Radio Frequency = Eight Time Slots One TDMA Frame = Eight Time Slots One Time Slot = One Physical Channel One Time Slot Duration = 0.577 msec
FDMA/TDMA SCHEME
890.0
890.2890.4
890.6890.8
891.0891.2 915.8
FREQ
MHz
BURSTF
R
A
M
E
BP1
BP2
BP3
BP4
BP5
BP6
BP7
BP8
BP1
BP2
TIME
8 7 6 5 4 3 2 1 FRAME OF 8 TIME SLOTS
FRAME REPETITION
PHYSICAL CHANNELS
8 7 6 5 4 3 2 1 8 7 6 5 4 3 2 1 8 7 6 5 4 3 2 1
8 7 6 5 4 3 2 1
11
1
1
1
1
2
2
2
2
2
3
3
3
3
3
4
4
4
4
4
6
6
6
6
6
7
7
7
7
7
8
8
8
8
8
5
5
5
5
5
PHYSICAL CHANNELS
12
45
67
8
3
CELLULAR MOBILE CONCEPTS
WHAT IS A CELL ?
A base station (transmitter) having a number of RF channels is called a cell Each cell covers a limited number of mobile subscribers
within the cell boundaries ( Coverage area)
Typical Cell Radius Approx. = 30 Km (Start up), 1 Km (Mature)
Each Cell uses a specific set of radio frequencies Each Base Station contains one or more TRXs
CELL RADIUS (KM)
COVERAGE AREA(KM2)
No. Of MOBILE SUBS.
No. of CHANNELS
REQD.
1 3.14 100 8
3 28.3 900 38
10 314 10,000 @ 360
25 1960 60,000 @ 2,000
ASSUMPTIONS Traffic /User = 30 mE , GOS = 1%
CELLULAR MOBILE CONCEPTS
• 360 * 25 KHz * 2 = 18 000 KHz = 18 MHz FOR A CELL OF 10 KM RADIUS ONLY
• THIS IS IMPOSSIBLE TO BE ALLOCATED
• HENCE FREQUENCY REUSE IS A MUST TO COVER THE TOTAL SERVICE AREA WITH A LIMITED AVAILABLE RF RESOURCES
• HENCE THE NEED FOR A CELLULAR PRINCIPLE
CELLULAR MOBILE CONCEPTS
CELLULAR MOBILE CONCEPTS
CO-CHL INTERFERENCE :Interference caused by another cell/mobile using the same frequency
D
R
Co Chl Interference is a Function of “Q”the re-use ratio:
Q =D / R
Lower Q Increased Co-Chl Interference
Higher Q Reduced Co-Chl Interference
Co– Channel Interference
Q = D /R = 3N
N =Cluster SizeR = Size (Radius of Cell)D = Distance between two Co- Channel Cells
Higher Q Less Interference Higher NMore Cluster SizeLess RF freq/cellLess Traffic HandlingCapacity of the system
LOWER Q Higher Interference Increased System Handling Capacity
Higher Q Less Interference Higher NMore Cluster SizeLess RF freq/cellLess Traffic HandlingCapacity of the system
Co– Channel Interference
MODULATION GMSK = GAUSSIAN MINIMUM SHIFT
KEYING The modulation method in GSM is GMSK
which facilitates the use of narrow bandwidth and coherent detection capability.
Rectangular pulses are passed through a Gaussian filter prior to their passing through a modulator.
GSMVARIOUS SUBSYSTEMS1. Network Subsystem includes the
equipments and functions related to end-to-end call.
2. Radio Subsystem includes the equipments and functions related to the management of the connections on the radio path.
3. Operations and Maintenance subsystem includes the operation and maintenance of GSM equipment for the radio and network interface.
GSMNETWORK STRUCTURE GSM Service Area: Total area served by the
combination of all member countries where a mobile can be served.
PLMN Service Area:It is one N/W area. MSC Service Area:There can many MSC/VLR
in one PLMN area.It is one Mobile Exch. Area.
GMSC: All I/C calls for PLMN N/W will be routed through GMSC. In a GSM/PLMN N/W all mobile terminated calls will be routed to a Gateway MSC. Call connections between PLMNs , or to fixed N/Ws must be routed to a GMSC.The GMSC contains the Inter working functions to make these connections.
Location Area Cells
LOCATION AREA:There are several LA in a MSC/VLR combination A LA is a part of the MSC/VLR service area in which a MS may move freely without updating location information to the MSC/VLR exchange that control the LA. Within a LA a paging message is broadcast in order to find the called mobile subs. LA can be identified by system using the LAI.
CELL.A cell is an identity served by one BTS. The MS distinguishes between cells using the BASE STATION IDENTIFICATION CODE(BSIC) that the cell site broadcast over the air.
GSMRELATION BETWEEN AREAS IN GSM
Location AreaCell
Area served by a BTS
Location Area
MSC Service Area
PLMN Service Area
GSM Service Area
NETWORK ARCHITECTURE
BTS
MSC VLR
HLR
PSTNISDN
DataNetworks
(
Air interface
OSS
BTS
BTS
MSC VLR
BSCBSC
1 MSC=16 BSC
1 BSC=1024 TRU
A Interface
A-bis interface
BSC:BASE STATION CONTROLLER, BTS: BASE TRANSRECEIVER STATION, OSS: OPERATION AND SUPPORT SUBSYSTEM.ss
CALL CONNECTIVITY
ESTABLISHMENT
How the call is connected between End to End Equipment. Irrelevant of end
equipment, it may be land phone or Mobile station
Call And Mobility Management
• RF channel overview & Modes of Mobile Station.• MS Initialization ( Network Attachment )
• Mobility Management and MM Procedures
• Connection Management (CM)
• Call Processing – MO & MT Calls
• Authentication & Location Updating Procedure
Modes Mobile Station ( MS )• MS Switched Off - can not receive incoming paging messages.
- can not make outgoing call.
- No dedicated channel is associated with it.
• MS Switched On - can receive incoming paging messages.
And in Idle Mode - can make outgoing call.
- No dedicated channel is associated with it.• MS in Dedicated Mode -MS is in conversation and a
dedicated traffic channel TCH is
associated with it.
RF Channels Overview
• Broadcast Control Channels - BCCH
P-MP FCCH
SCH• Common Control Channels PCH
P-P RACH
AGCH
• Dedicated Control Channels - SDCCH
P-P FACCH
SACCH
CM
CCSMS
SS
Normal Burst
3
T 57
Encrypted
1S
26
Training
1
S
57
Encrypted
3
T
8.25
GP
CM
CCSMS
SS3
T 142
Fixed Bits
3
T
8.25
GP
FCCH Burst
CM
CCSMS
SS
Possible Channel Combinations On RT in One Cell
RT 0
Timeslots
RT 1
RT 2
RT 3
BCCH CCCH CCCH
TCH
SDCCH
SDCCH TCH
0 1 2 3 4 5 6 7
TCH TCHCCCH
TCH TCH TCH TCH TCH TCH TCH
TCH TCH TCH TCH TCH TCH TCH TCH
TCH TCH TCH TCH TCH TCH TCH
CM
CCSMS
SS
Channel Combination IV :main BCCH ( GSM 05.01)
BCCHDown-link
Up-link
FCCH
SCH
0 1 2 3 4 65 7 9 118 10
CCCH
RACH
RACH
FCCH
SCH
12 13 1514 16
BCCH
5049. . .
IDLE
. . .RACH
Technical Terms Used w.r.t. MM (Mobility Management )
• IMSI – International Mobile Subscriber Identity
• IMSISDN – Mobile Subscriber ISDN number
• IMEI – International Mobile Equipment Identity
• TMSI – Temporary Mobile Subscriber Identity
• MSRN – Mobile Subscriber Roaming Number
• LAI – Location Area Identity
• A3 – Authentication Algorithm
• A5 – Ciphering Algorithm
• A8 – Kc Generation Algorithm
1. MSRN – Mobile Subscriber Roaming Number It is a temporary number used for routing the call to MS.
Format : MSRN = CC + NDC + SN
CC = Country Code
NDC = Network Destination Code
For example for Patna MSC in IMPCS network MSRN looks like 91 95330 24365.
SN = Subscriber Number
Location Related Identities
PSTN GMSC
HLR
MSCVLR
MSISDN
1
MSISDN 2
IMSI
3
IMSI MSRN 4
MSRN
5
MSRN 6MSRN
7
MSRN
Location Related Identities
• Location area consist of one or more than one cell which may be served by one or more BSC s.
• All the cells in a Location area are served by single VLR.
2. Location Area Identity (LAI ) -
• Each location area in a GSM PLMN is identified by a Location Area Identity ( LAI ).
Location Related Identities
HLRSS 7
BSC
MSC 2
VLR 1
VLR 2
BSC
BSC
BSC
LA 1
LA 2
LA 3
BTS
BTS
BTS
BTS
BTS
BTS
Location Area
MSC 1
LAI = MCC + MNC + LAC
MCC - Mobile Country Code.
MNC - Mobile Network Code.
LAC - Location Area Code .
• Maximum length of LAC is 16 bits.
• Thus there can be maximum of 65,536 Location Areas defined in one GSM PLMN.
MCC MNC LAC
3 digits 2 digits 2 octets max
LAI
( 16 bits )
Location Related Identities
MS Initialization / Network Attachment
1. MS Powered on.
- FCCH present in time slot T0 & has a fixed pattern of 142 0’s.
- MS scans entire 124 carriers and monitors RF levels. - several readings are taken to get accurate estimate
the channel power.
- MS then searches for Frequency Correction burst (FCCH) on the channel with strongest RF level.
2. Frequency Synchronization
- After tuning to FCCH MS synchronizes in time with SCH .
- SCH occurs in next frame in same time slot as FCCH.
- The occurrence of SCH is eight burst period ( BP’s ) later than FCCH.
3. Synchronization in Time
- After successful synchronization the MS will read the TDMA frame number and Base Station Identity Code BSIC .
- SCH contains precise timing information and current frame number to which MS is synchronized.
- BSIC consists of - PLMN colour code ( 3 bits )
- BS colour code ( 3 bits ).
MS Initialization / Network Attachment
• MS decodes information on BCCH and gets Location Area Identity ( LAI ).
• If the information stored on SIM does not match with the information MS thinks that it has moved to new location and sends LA update request to BSS.
• MS location is determined by cell identification of strongest BCCH signal received by MS.
• MS regularly measures the received signal strength of BCCH at least once every 6 sec ( Superframe Duration).
• MS stores at least six strongest BCCH and their cell identification in SIM.
MS Initialization / Network Attachment
Network Attachment Process
MS
. Cell should be of selected PLMN.
Switch -on
Measure strongest BCCH channels
PLMN Selection
Cell Selection
Location Update
Idle-Mode
. Cell should not be “ barred “.
. Radio path loss between BTS and the MS must be below a threshold set by the operator. ( Register its presence
to the network. )
Limited Service Mode
MS BTS MSCBSC
RIL3 - CM
LAPD m
Layer 1
RIL3 - MM
RIL3 - RR
Layer 1
LAPD m LAPD
Um
A bis A link BCDEFG
MTP
SCCP
BSSMAP
DTAP MM
TCAP
DTAP CM
U
PSCCP
MAP
Layer 1Layer 1
GSM Signaling Protocols Overview
LAPD MTP
I
S
SCCP
BSSMAP
BTSM
RIL 3-RR
BTSMRR
What is Mobility Management ( MM ) ?
Subscriber Data management at MSC/VLR
• Subscriber data from HLR are retrieved by MM at the time of first location up-dating of a subscriber.
• Dynamic data changes by subscriber are also managed by MM at MSC/VLR.
• Operator initiated data changes for a subscriber are also managed by MM.
Services Provided to Upper Layers
• MM sub-layer provides basic services to upper layer CM sub-layer.
• MM handover procedures provide smooth transition from one radio link to other.
What is Mobility Management ( MM ) ?
Subscriber Authentication and Confidentiality management
• MM procedures ensure authenticity of a subscriber.
• MM procedures ensure data confidentiality at radio interface.
MM Procedures
• TMSI Reallocation Procedure.
• IMSI Detach Procedure.
• Ciphering Procedure.
• Abort Procedure.
MM Common Procedures :
• Authentication Procedure.• Identification Procedure.
MM Specific Procedures :
• Location Updating Procedure.• IMSI Attach Procedure.
• During the lifetime of a MM specific procedure if a MM connection establishment is requested by a CM entity, the request will either be rejected or delayed until the running of MM specific procedure is terminated.• Any MM common procedure Procedure ( except IMSI detach) may be initiated during MM specific procedure.
• A MM specific procedure can only be started if no other MM specific procedure is running.
• The MS side should wait for release of RR connection used for a MM specific procedure before a new MM specific procedure or MM connection establishment is started.
MM Procedures
Authentication
• Authentication is used to check the validity of a mobile subscriber.
At MS At N/W
KiRAND( 128 bits )
Ki
A3 A3
SRES SRES
( 32 bits )=?
AUTHENTICATION
• RAND ( 128 bits ):Random Number
• SRES ( 32 bits) :Signed Response
• Kc ( 64 bits ) : Ciphering Key
- Ki is stored in SIM and HLR.
• Ki ( 128 bits) : Identification Key
- Purpose : Ki is used to calculate SRES and Kc.
- Ki is never transmitted over signaling network.
- Purpose : Kc is used to encrypt data over radio interface.
- Purpose : RAND is used to calculate SRES and Kc.
Ciphering
• Ciphering is used to encrypt data on radio interface.
Frame No. (22 bits )
A5
Information Bits ( 114 bits )
CIPHERING
Kc generation is done at the time of Authentication.
RAND Ki
Kc ( 64 bits)
A8
Ciphering Stream
XORCiphered Bits
1. To check identity provided by the MS.
The purpose of authentication procedure is two fold :
2. To supply n/w parameters to MS to calculate Kc.
• Authentication procedure is always initiated and controlled by the n/w.
TIME
MS N/W
Authentication Request
Authentication Response
Authentication Reject
AUTHENTICATION PROCEDURE
Authentication Procedure
Authentication Procedure
- At n/w side, authentication procedure requires authentication triplets.
Authentication Triplets :
-RAND ( 128 bits ).
- Authentication triplets contains
- SRES ( 32 bits ). - Kc ( 64 bits ). - The network can have more than one triplets. - The operator can allow reuse of triplets. - The index of currently used triplet is called CKSN ( Ciphering Key Sequence Number ).
Location Updating Procedure
• Normal Location Updating -
MS moves to new LA.
This is a general procedure which is used for following purposes -
• Periodic Location Updating -
To notify periodic availability of MS to the network.
• IMSI Attach -
MS switched on for first time in new LA or MS switched off and on.
Each time MS moves to new LA corresponding VLR is informed.
Case - I Old LA and new LA in same VLR area
• MS given new TMSI .
• Location updated in VLR memory.
Case - II Old LA and new LA in different VLR area
• HLR updates.• old VLR erases data.• new VLR records relevant parameters.
• MS is given new TMSI.
Location Update Scenario
Location Update Scenario
Phases of Location Update Scenario
• Request for service.
• Authentication
• TMSI reallocation.
• Ciphering
• HLR/ VLR updation
LOCATION UPDATE SCENARIO - I
MS BSSOld MSC/ VLR
HLR /AUC
New MSC/ VLR
1
2
Channel Request
RACH
AGCH
SDCCH Assignment
Location Update Request ( TMSI , LAI 0 )
SDCCH3
Request IMSI
Send IMSI4
Request For Service
( TMSI )
MS BSSOld MSC/ VLR
HLR/ AUC
New MSC/ VLR
5
6
Get Authentication Parameters
Authentication Response ( SRES )
SDCCH
7
( IMSI )
( RAND,Kc,SRES )
Authentication Parameters
SDCCH
Authenticate MS ( RAND )
Cipher Radio Channel
( Kc )
Cipher Up Link Channel
SDCCH
Authentication and Ciphering
LOCATION UPDATE SCENARIO - II
8
9
BSS Ciphers Down link Channel .
SDCCH
Ciphering Complete
MS BSSOld MSC/ VLR
HLR/ AUC
New MSC/ VLR
LOCATION UPDATE SCENARIO - III
Authentication and Ciphering
Up Link Ciphered
LOCATION UPDATE SCENARIO - IV
10
Update Location
Update HLR/VLR & TMSI Reallocation
De Register Mobile
Mobile De-registered11
MS BSSOld MSC/ VLR
HLR/ AUC
New MSC/ VLR
Location Updated
Location Updated Accept TMSI
SDCCH
12
13
SDCCH
Location Updated Complete
Clear Signaling Connection
Clear Complete
Release Radio Signaling Channel
SDCCH
14
16
15
MS BSSOld MSC/ VLR
HLR/ AUC
New MSC/ VLR
LOCATION UPDATE SCENARIO - V
Update HLR/VLR & TMSI Reallocation
TAX CA
TAX ND
GMSC MSC
GMSC MSC/VLR
ND Mobile moves to CA and Powers on MS
CA
ND
HLR
HLR
ND
MS
9810098111CA
ND
( Update Location/ Authentication )
De register Mobile to Old VLR
ACK from old MSC/VLR
VLR
LOCATION UPDATION
VLR
VPLMN
HPLMN
Location Update
( TMSI, LAI )
LU Accept
( New TMSI)
Update Location
Update Location
LU Accept
(Subs data)
LU Accept
Update Location
LU Accept
LU Accept
New VLR records subscriber data.
• ListensBCCH/FCCH
Mobile To Land Call Set-up Scenario
Phases of Mobile To Land Call
• SETUP PHASE
( Mobile Originated Call- MO Call )
• RINGING PHASE
• CONVERSATION PHASE
• RELEASE PHASE
- REQUEST FOR SERVICE ( CHANNEL ) BY MS
- CM SERVICE REQUEST
- AUTHENTICATION
- CIPHERING
- SETUP MESSAGE
- EQUIPMENT VALIDATION ( EIR CHECK )
- VALIDATION AT VLR
- ASSIGNMENT
Mobile To Land Call Set-up Scenario
• SETUP PHASE
MSMSC/VLR BSS
1
2
3
Channel Request
Request For Service
MOBILE TO LAND CALL - I
RACH
SDCCH Assignment
AGCH
CM Service Accept
SDCCH
4
CM Service Request
Mobile To Land Call Set-up Scenario
• CM SERVICE REQUEST
- The Call Control (CC) entity of MS initiates the establishment of CC connection by requesting MM sub-layer of the mobile to establish MM sub-layer connection.
- Upon establishment of MM connection CM SERVICE ACCEPT message is received from n/w.
• SETUP MESSAGE
- CC entity sends a setup message to its peer entity.
MSMSC/VLR BSS
5
6
Call Setup Request
7
SDCCH
SDCCH
Call SetupMOBILE TO LAND CALL - II
Assign Trunk and radio
Assign TCH
Radio Assignment Complete
Call Proceeding
SDCCH
SDCCH
Trunk and Radio Assignment Complete
Mobile To Land Call Set-up Scenario
MSC/VLR
Call Setup message
Is the requested basic service
provisioned for the subscriber ?
Yes
No
Release Complete
message to MS
Preliminary Digit Analysis
Is the number of digits less than the
minimum expected?
Yes
Release Complete
message to MS
No 1. Check of ODB( BAOC/BOIC/ BOIC Ex HC )
2. Subscriber call barring checks ( BAOC/BOIC etc. )
ASSIGNM ENT
Mobile To Land Call Set-up Scenario
• ASSIGNMENT
- A BSSMAP message ‘Assignment Command ’ is sent by MSC to BSS.
- The message contains a free CIC on A-Interface for terrestrial channel allocated by MSC.
- A free TCH is allocated by the BSS and MS is informed to attach to this TCH.
- On receiving a response from BSS MSC switches the speech path towards the calling MS.
Note : Mobile has not connected user connection as yet.
MSMSC/VLR BSS
8
9
10
11
Call Setup MOBILE TO LAND CALL - III
GMSC PSTN HLR
Network Setup ( Dialed Digits )
FACCH
Network Alerting
Connect
Connect Acknowledge
FACCH
Alerting
Connect
FACCH
Start Billing
MSMSC/VLR BSS
12
13
14
15
Call Release
MOBILE TO LAND CALL - IV
GMSC PSTN HLR
Disconnect
FACCH
Network Release
Release Complete
Release Complete
FACCH
Release
FACCH
Clear Command
Channel Release
Land To Mobile Call Set-up Scenario
Phases of Land To Mobile Call
• Routing Analysis
• Paging
• Authentication
• Call-Setup
• Ciphering
• Call Release
( Mobile Terminating - MT Call )
Architecture For Mobile Terminated Call
GMSC- B BSS-B
MS
VLR-B
MSC-B
VISITING PLMN
A- Interface
Air Interface
AC
K (
MS
RN
)
SR
I ( MS
ISD
N ) P
RN
AC
K ( M
SR
N )
HLR-B
IAM ( ISUP )
LAND TO MOBILE CALL - I
MSC/VLR GMSC PSTN HLR
1
2
Incoming Call
3
4
( MSISDN )Get Route
( MSISDN )Get Route
( IMSI )
Routing Information
( MSRN ) Routing Information
( MSRN )
( MSRN )
Incoming Call5
Routing Analysis
MS MSC BSS
6
7
8
Perform Page
(TMSI)Page
PCH
Channel Request
( RACH )
SDCCH
Paging Response
( TMSI, LAI )9
Access Granted
( AGCH )
Page Response
Paging
LAND TO MOBILE CALL - II
MS MSC BSS
10
11
12
Call Set Up
Call Set Up Confirm
SDCCH
Radio Channel Assigned
Assign Trunk & Radio Channel
Trunk and Radio Channel Assignment Complete
SDCCH
SDCCH
Assign Radio Channel
SDCCH
Call Set-up
LAND TO MOBILE CALL - III
MSMSC/VLR BSS
13
14
15
Connect ( off-hook )
FACCH
Call SetupLAND TO MOBILE CALL - IV
GMSC PSTN HLR
FACCH
Network Alerting
Mobile Alerting
Connect
Connect Acknowledge
Start Billing
MSMSC/VLR BSS
16
17
18
Disconnect
Release
19
FACCH
FACCH
Call ReleaseLAND TO MOBILE CALL - V
GMSC PSTN HLR
Network Release
FACCH Release Complete
Release Complete
Clear Command
Clear Channel
Clear CompleteFACCH
Stop Billing
TAX ND
GMSC MSC/VLR
1. ND PSTN Subscriber Dials ND Mobile Subscriber in ND.
ND
LE TANDEM
HLR
ND
MS
9810098100NDSRI
PRN to MSC/VLR
ND
ACK from MSC/VLR
ND (MSRN)
MSRN
MSISDN
MSISDNMSISDN
Page(TMSI)
TAX ND
TAX CA
GMSC MSC/VLR
GMSC MSC/VLR
2. ND PSTN Subscriber Dials CA Mobile Subscriber in CA.
ND
CA
LE
HLR
HLR
CA
MS
9881098300
ND
CA
SRI
PRN to MSC/VLR
CA
ACK from MSC/VLR CA (MSRN)
MSRN
MSISDN
Page(TMSI)
TANDEM
MSISDN
MSISDNMSISDN
TAX CA
TAX ND
GMSC MSC/VLR
GMSC MSC/VLR
3. ND PSTN Subscriber Dials ND Mobile Subscriber in CA.
CA
ND
LE TANDEM
HLR
HLR
ND
MS
9810098200CA
NDSRI
PRN to MSC/VLR
CA
ACK from MSC/VLR CA (MSRN)
MSRN
MSRN
MSRN
MSRN
MSISDN
MSISDNMSISDN
Page(TMSI)
TAX CA
TAX ND
GMSC MSC/VLR
GMSC MSC/VLR
4. CA PSTN Subscriber Dials ND Mobile Subscriber in CA.
CA
ND
LE
HLR
HLR
ND
MS
9810098400
CA
ND
SRI
PRN to MSC/VLR
CA
ACK from MSC/VLR CA (MSRN)
MSRN
MSISDN
Page(TMSI)
TANDEM
MSISDN
MSISDNMSISDN
MSRN
MSRN
MSRN
What is Optimization ?
- Activity of achieving and maintaining the required quality as designed
Why Optimization ?
- Deviations between plan and reality
Introduction
Optimum utilization of GSM Net work elements for providing Good Coverage and Better Speech Quality for satisfaction of Subscriber and achieving the “TRAI” bench marks of QoS
Objective OF RF OPTIMIZATION
TRAI Bench Marks for QOS 1. Call Setup Success Rate > 98%
2. Handover Success Rate > 98%
3. Co Channel Interference > 98%
4. Rx.Quality(0-5) > 95%
5. Drop Call Rate < 3%
6. TCH Blocking Rate < 2%
7. SDCCH Blocking Rate < 1%
RFOptimization identifies common problems, such as:
1.Missing neighbors
2.Antenna adjustments
3.Issues of inter system handovers, Power control
4.Interference
5.Coverage gap, overlap coverage, etc.
A. VISIT BTS SITE & COLLECT THE FOLLOWING INFO :
1. Height of Antenna
2. Antenna Azimuth – Orientation
3. Antenna tilt
4. Checking of RF connectors
5. Verification of serving area by existing Antenna orientations
6. TX Power of TRX
B. DATA FROM OMC-R :
7.Data Base – Change of cell parameters
8.Cell Wise Performance Reports
a). SDCCH congn. b). TCH congn. C). Call Volume
d). Drop Call Rate e). Handover Success Rate
f). U/L & D/L quality & Interference.
Pre Requirements for Drive Test :
DRIVE TEST :
Tool may be setup for two mobiles –
One for Continuous call and another for short calls(2min)
Conduct the Drive Test –
covering all sectors by observing the following parameters.
1. Rx Level
2. Rx Quality
3. Interference
4. Handovers & Drop Calls
5. Observe whether the nearest sector is serving or not.
No. of BTS in SSA : No. of BTS s covered in the month :
Ch.Gutta-Katedan-Attapur-
M.Patnam-TPBVN
CHRMNR-Ch.Gutta
CTO-Tarnaka-
Uppal
Shivam-VDNR-STPM-
Sec.bad Rly. Stn.-
CTO
Sanath Nagar-
Balkampet-BGMPT-
CTO
TPBVN-MSRBD-
Ramnagar-VDNR
TPBVN-Abids-Koti-
Namply-L.Pool
TPBVN-AfglGunj-CHRMNR
Uppal-AMBRPT-
Chdr.Ghat-Cachiguda-
TPBVN
1 RX LEV. Total no. Of Samples 11309 3537 7776 9586 6715 7731 7886 4961 9553>=-75dBm 11187 3534 7677 9572 6609 7495 7786 4573 9434
%Samples >=-75dBm 99 99.91 99 100 98 97 99 92 99
2 RX. Qual. Total No.Of Samples 11313 3536 7776 9586 6715 7731 7886 4961 95530 to 5 10929 3198 7366 9290 5989 7046 6837 4669 8786
0-5(>=95%) 97% 90% 95% 97% 89% 91% 87% 94% 92%
3 Hand Over H/O Attempts 74 12 39 35 37 34 20 39 39Dropped 42 0 0 0 1 1 0 2 0
H/O Success rate 56% 100% 100.00% 100% 98% 98% 100% 95% 100%
4 Aggregate C/I Total 1755 547 1096 1630 794 982 889 464 1432C/I>9 1737 513 1035 1605 773 952 847 451 1383
%Samples with C/I>9 99% 94% 94% 98% 97% 97% 95% 97% 97%
5 Call Analysis Total calls 25 10 17.00 20 14 13 17 12 22Good 24 8 16 20 14 13 16 11 19
Success Rate 96% 80% 94% 100% 100% 100% 94% 92% 86%
Blocked Calls 0 0 0 0 0 0 1 0 1Dropped 1 2 1 0 1 0 1 1 2
Call Drop rate 4% 20% 6% 0% 7% 0% 6% 8% 9%
6Service Access Delay
9 - 20Seconds (average of 100 calls <=15 Sec.)
7.2 7.3 7.12 7.2 7% 7.4 7.1 7.3 7.9
In addition the above formate Route map also submit with Rx level and Rx qual, & survey markers Like H/o ,Call drop ,H/o failure
Drive Test Results
Name of The SSA : Hyderabad
Details of Parameter Routes/Towns
Sl.No
Analysis of Drive Test Results :Observation Cause Solution
Coverage Poor (Low RX
Level)
1. Antenna Orientations & TiltPhysical check of Orientations & Tilt.
2. High VSWR Value Check RF connectors & RF cables
3. TX PowerCheck the DRX power & connectors
Poor RX Quality
1. Intereference
Check the BCCH & MAIO frequencies
Reduction of Antenna height, Orientation & Tilt
2. Low Rx levelCheck the DRX power & connectors
3. H/O failureCheck the neighbour list & definitions
Check the neghbour parameters
4. Assignment Failure RatioCheck DRX & Check VSWR & RF cable connectivity
5. Hard Ware Problem DRX problem
Analysis of Drive Test Results :Observation Cause Solution
Handover Failure
1. Not defining proper neighbours
Defining the proper neighbours.
2. Improper Neighbour Parameter values
Check the neghbour parameters
3. Due to TCH congn. Augmentation of DRIs
Call Drop
1. Not defining proper neighbours
Defining the proper neighbours.
2. Low Rx level Check the DRX power & connectors
3. Intereference
Check the BCCH & MAIO frequencies
Reduction of Antenna height, Orientation & Tilt
4. H/O failure
Check the neighbour list & definitions
Check the neghbour parameters
5. Assignment Failure RatioCheck DRX & Check VSWR & RF cable connectivity
6. Hard Ware Problem DRX problem