![GSM Frequency Spectrum
1] GSM 900
1] GSM 900
Uplink
Uplink : 890 MHz to 915 MHz
: 890 MHz to 915 MHz
GSM Spectrum
Downlink : 935 MHz to 960 MHz
Downlink : 935 MHz to 960 MHz
ARFCN
ARFCN : 124
: 124
2] EGSM 900
2] EGSM 900
Uplink
Uplink : 880 MHz to 915 MHz
: 880 MHz to 915 MHz 3] GSM 1800 (DCS 1800)
3] GSM 1800 (DCS 1800)
Downlink : 925 MHz to 960 MHz
Downlink : 925 MHz to 960 MHz Uplink
Uplink : 1710 MHz to 1795 MHz
: 1710 MHz to 1795 MHz
ARFCNs : 174
ARFCNs : 174 Downlink : 1805 MHz to 1880 MHz
Downlink : 1805 MHz to 1880 MHz
ARFCNs : 374
ARFCNs : 374
Absolute Radio Frequency Channels : 4] PCS 1900
4] PCS 1900
BW - 200 KHz, TDMA Slots - 8 Uplink
Uplink : 1850 MHz to 1910 MHz
: 1850 MHz to 1910 MHz
Downlink : 1930 MHz to 1990 MHz
Downlink : 1930 MHz to 1990 MHz
ARFCNs : 299
ARFCNs : 299 GGRajan](https://image.slidesharecdn.com/gsmtechnology-110929125504-phpapp02/85/Gsm-technology-4-320.jpg)
![GSM Frequency Spectrum
GSM Spectrum [900 MHz]
Time
Code
• UL band : 890 - 915 MHz
• DL band : 935 - 960 MHz TS-8
• Duplex spacing: 45 MHz
A
FDMA structure: 124 RFs (ARFCN) TS-2
M
•
TD
TS-1
• RF Band width: 200 KHz
Freq
• TDMA structure: 8 Timeslots/ RF RF-1 RF-2 RF-3
FDMA
960 Mhz
124
•
•
RF • 1 2 3 4 5 6 7 8
•
2 TDMA structure of each ARFCN
1
935 Mhz
GGRajan](https://image.slidesharecdn.com/gsmtechnology-110929125504-phpapp02/85/Gsm-technology-5-320.jpg)
![SIM Anatomy
Programs in SIM
1 . IMSI (International Mobile Station Identity)
2 . Ki (Individual Subscriber authentication Key)
3 . A3 (Authentication Algorithm )
4 . A8 [ Cipher Key (Kc) Algorithm ]
IMSI
Ki
5 . A5 (Encryption Algorithm ) A3
A8
• IMSI & Ki are specific to each MS A5
• A3 & A8 can be different for different operators
• A5 - Unique, used across GSM operators
GGRajan](https://image.slidesharecdn.com/gsmtechnology-110929125504-phpapp02/85/Gsm-technology-27-320.jpg)
More Related Content
Gsm technology
- 1. Presentation by G. Govindarajan Dy. General Manager (Rtd) Mahanagar Telephone Nigam Limited (MTNL) Mumbai GGRajan
- 2. GSM Spectrum Cell Principles Sectorisation Frequency Planning GGRajan
- 3. RADIO SPECTRUM GGRajan
- 4. GSM Frequency Spectrum 1]GSM 900 1] GSM 900 Uplink Uplink : 890 MHz to 915 MHz : 890 MHz to 915 MHz GSM Spectrum Downlink : 935 MHz to 960 MHz Downlink : 935 MHz to 960 MHz ARFCN ARFCN : 124 : 124 2] EGSM 900 2] EGSM 900 Uplink Uplink : 880 MHz to 915 MHz : 880 MHz to 915 MHz 3] GSM 1800 (DCS 1800) 3] GSM 1800 (DCS 1800) Downlink : 925 MHz to 960 MHz Downlink : 925 MHz to 960 MHz Uplink Uplink : 1710 MHz to 1795 MHz : 1710 MHz to 1795 MHz ARFCNs : 174 ARFCNs : 174 Downlink : 1805 MHz to 1880 MHz Downlink : 1805 MHz to 1880 MHz ARFCNs : 374 ARFCNs : 374 Absolute Radio Frequency Channels : 4] PCS 1900 4] PCS 1900 BW - 200 KHz, TDMA Slots - 8 Uplink Uplink : 1850 MHz to 1910 MHz : 1850 MHz to 1910 MHz Downlink : 1930 MHz to 1990 MHz Downlink : 1930 MHz to 1990 MHz ARFCNs : 299 ARFCNs : 299 GGRajan
- 5. GSM Frequency Spectrum GSM Spectrum [900 MHz] Time Code • UL band : 890 - 915 MHz • DL band : 935 - 960 MHz TS-8 • Duplex spacing: 45 MHz A FDMA structure: 124 RFs (ARFCN) TS-2 M • TD TS-1 • RF Band width: 200 KHz Freq • TDMA structure: 8 Timeslots/ RF RF-1 RF-2 RF-3 FDMA 960 Mhz 124 • • RF • 1 2 3 4 5 6 7 8 • 2 TDMA structure of each ARFCN 1 935 Mhz GGRajan
- 6. GSM Frequency Spectrum B T S 890 MHz 915 MHz 935 MHz 960 MHz 1 2 3 124 1 2 3 124 UPLINK FREQUENCY DOWNLINK FREQUENCY GGRajan
- 7. Cell Principles CELL :a Base Station (Transmitter) having number of RF channels. Usually a Hexagonal shape. 2 7 3 CLUSTER: Group of cells. 1 Size > 3, 4, 7, 9 or 12 6 4 5 GGRajan
- 8. Cell Principles COVERAGE AREA Each Cell covers a limited number of - 70 dBm Mobile Subs within the Cell boundaries. - 80 dBm - 90 dBm - 100 dBm GGRajan
- 9. Cell Principles CELL RADIUS: Radial distance of a Cell Approximately : 25 KMs ( Start up ) 1 KM ( Mature ) CELL SIZE : Large Cells are employed in: Remote areas Coastal regions Areas with few subscribers Small cells are used in: Urban areas Areas with high subscriber density GGRajan
- 10. Cell Principles Frequency Reuse GSM has 124 frequencies for use in network Allocated to more than one network operator If 4 operators, then each will get only 31 frequencies Maximum cell radius is approximately 35 KMs Network provider must re-use the same frequencies 2 7 3 Q = D/R = 3N (if all cells 1 with same Radius) R 6 4 N - Cluster size, R - Cell Radius D - Distance between two co-channels 5 D High Q > Less interference – Less Traffic capacity 1 Low Q > Higher interference – Higher capacity GGRajan
- 11. Cell Sectorisation Omni Antenna 3 Sectored Cell Site 6 Sectored Cell Site F2 1 1 6 2 3 F1 5 3 2 4 F3 Sectorisation splits a single site into a number of cells Each sector cell has TX and RX antennas Each sector behaves as an independent cell GSM = 4/12 : 4 Cell Sites, each with 3 Sectors DAMPS = 7/21 : 7 Cell Sites, each with 3 Sectors CDMA = 1/3 : 1 Cell Site, each with 3 Sectors GGRajan
- 12. Cell Sectorisation 3 SectoredCell Site GGRajan
- 13. Frequency Planning 4 / 12 Layout A1 B1 C1 D1 A2 B2 C2 D2 A3 B3 C3 D3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 A1 A2 D1 A3 B1 D2 B2 A1 C1 D3 B3 A2 C2 D1 A3 B1 C3 D2 B2 D3 C1 B3 C2 C3 GGRajan
- 14. Frequency Planning A1 B1C1 A2 B2 C2 A3 B3 C3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 3 / 9 Layout 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 A1 A1 A2 A2 A3 B1 A3 B1 B2 B2 C1 B3 C1 B3 C2 C2 C3 A1 C3 A2 A3 B1 B2 C1 B3 C2 C3 GGRajan
- 15. Frequency Planning Typical CellularRadio Plan GGRajan
- 16. GSM Architecture SIM Anatomy BSS Architecture NSS Architecture GGRajan
- 17. GSM Architecture GSM SYSTEM Base Station Switching OMC /NMC Subsystem Subsystem Subsystem Base Station Mobile Switching Controller (BSC) Centre (MSC) Base Transceiver Registers AUC Station (BTS) HLR VLR EIR GGRajan
- 18. GSM Architecture NSS MSC/VLR BSS Architecture BSC BSC Abis BTS BTS BTS BTS MS MS MS MS GGRajan
- 19. GSM Architecture BTS: Base Transceiver Station NSS Architecture BSC: Base Station Controller MSC: Mobile Switching Center PSTN PSTN VLR: Visiting Location Register HLR: Home Location Register GMSC NSS IWF: InterWorking Function HLR / AuC SS7 SS7 VLR STP MSC EIR CSE IWF SM-SC MSC / VLR VMS Internet Internet BSS BSC BTS BTS MS GGRajan
- 20. GSM Architecture BTS Functions ◄Encodes, Encrypts, Multiplexes, Modulates and feeds RF to Antenna ◄Received signals is Decoded, Decrypted and Demodulate ◄Trans-coding and Rate Adoption Functionality ◄11 power classes from .01 watts (Micro cell) to 320 watts ◄Frequency hopping NOKIA BTS ◄Up-link radio channel measurements ◄Multiple Antennas for Diversity LUCENT BTS GGRajan
- 21. GSM Architecture BSC Functions Allocation of radio channels Receives MS measurements Inter-cell handovers from BTS to BTS Concentrator for low capacity BTSs Reduce the number of connections to MSC Data stored in BSC ►Carrier frequencies ►Frequency hopping lists ►Power reduction levels ►Levels for cell border calculation GGRajan
- 22. GSM Architecture MSC Functions Paging, specifically call handling Dynamic allocation of resources in coordination with BSS Location registration Handover management Billing for all subscribers based in its area Reallocation of frequencies to BTSs to meet heavy demands Signaling interface to databases like HLR, VLR. Gateway to SMS between SMS centers and subscribers Handle inter working function while working as GMSC GGRajan
- 23. GSM Architecture Visitor Location Register IMSI & TMSI IMSI & TMSI MSISDN MSISDN VLR Data MSRN MSRN Location Area Location Area MS category MS category Authentication Key Authentication Key Main task of VLR is to reduce the number of queries to HLR Controls those mobiles Roaming in its area. One VLR may be in-charge of one or more LA. VLR gets updated from HLR, whenever a new MS enters its area. Authentication along with HLR and AUC. Relays ciphering key from HLR to BSS. Assign TMSI and periodically changes to secure MS’s identity. IMSI detach and attach operation GGRajan
- 24. GSM Architecture Home Location Register ►Stores ►Stores MS MS Parameters, Parameters, Numbers, Numbers, Authentication & Encryption values. Authentication & Encryption values. ►Current MS status and associated VLR. ►Current MS status and associated VLR. ►One PLMN may contain one or several HLR. ►One PLMN may contain one or several HLR. Authentication Centre ►Protect against intruders in air interface ►Protect against intruders in air interface ►Authentication (Ki) and Ciphering (Kc) keys stored ►Authentication (Ki) and Ciphering (Kc) keys stored securely securely ►Cipher key changes randomly with each phone call ►Cipher key changes randomly with each phone call ►A separate entity and physically included in HLR ►A separate entity and physically included in HLR GGRajan
- 25. GSM Architecture Equipment Identity Register Stores IMEI for all registered MS and is unique to every MS. Only one EIR per PLMN. White list : IMEI, assigned to valid MS. Black list : IMEI reported stolen Gray list : IMEI having problems like faulty software, wrong make of equipment etc. GGRajan
- 26. SIM Anatomy SIM (Subscriber Identification Module) A removable card. Contains an IC chip with a microprocessor. Contains RAM and ROM. It is inserted in ME at the time of making or receiving a call. GGRajan
- 27. SIM Anatomy Programs in SIM 1 . IMSI (International Mobile Station Identity) 2 . Ki (Individual Subscriber authentication Key) 3 . A3 (Authentication Algorithm ) 4 . A8 [ Cipher Key (Kc) Algorithm ] IMSI Ki 5 . A5 (Encryption Algorithm ) A3 A8 • IMSI & Ki are specific to each MS A5 • A3 & A8 can be different for different operators • A5 - Unique, used across GSM operators GGRajan
- 28. SIM Anatomy SIM AuthenticationProcess VLR IMSI RAND RAND Ki Ki Ki Ki A3 A8 A3 A8 Kc Kc SRES SRES SIM in MS NET WORK GGRajan
- 29. SIM Anatomy MSISDN Numbering for Cellular Mobile Network ACCESS MSC CODE MOBILE CODE NUMBER 2-digit 3-digit 5-digit 98/94 etc. ABC XXXXX GGRajan
- 30. GSM Architecture -Review NMC NMC VLR VLR HLR AUC OMC OMC EIR MSC MSC Terrestrial Interfaces MSC MSC XC IWF EC EC IWF XC BTS BTS BSC BSC BTS BTS BSC BSC BTS BTS PSTN PSTN BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS GGRajan
- 31. Physical & LogicalChannels Traffic & Control Channels TDMA Frames Super & Hyper Frames GGRajan
- 32. GSM Channels Physical Channels GSM RF carrier can support up to 8 MS simultaneously Each MS occupy 1 Time Slot Information carried in TS is “BURST” Each TS carrying Burst is a “Physical Channel” 8 Time Slots forms 1 TDMA Frame GGRajan
- 33. GSM Channels Logical Channels One or more logical channels are transmitted on a Physical channel. Determined by the information transmitted over it. Types of Logical Channels Logical Channels Logical Channels Traffic Channels Control Channels Broadcast Common Control Dedicated Control GGRajan
- 34. GSM Channels Traffic Channels on Air Interface TCH (Traffic Channel) TCH (Traffic Channel) NB NB SPEECH SPEECH DATA DATA TCH/FS TCH/FS TCH/HS TCH/HS TCH/9.6 TCH/9.6 TCH/2.4 TCH/2.4 TCH/EFR TCH/EFR TCH/4.8 TCH/4.8 SACCH SACCH NB: NB: Normal Burst Normal Burst TCH TCH SACCH: Slow Associated Control Chl. SACCH: Slow Associated Control Chl. FACCH: Fast Associated Control Chl. FACCH: Fast Associated Control Chl. FACCH FACCH GGRajan
- 35. GSM Channels Traffic channel Types Traffic channels are used to send Speech or Data services. May also be used for sending information. Example: call forwarding and short messages Traffic channel Types based on transmission rates TCH/FS (Full rate Speech) - gross bit rate of 22.8 kbps TCH/HS (Half rate Speech) - gross bit rate of 11.4 kbps GGRajan
- 36. GSM Channels Control Channels CCH (Control Channel) CCH (Control Channel) NB NB/AB BCCH- BCCH- DCCH DCCH Downlink Only Downlink Only NB/DB SDCCH SDCCH ACCH ACCH BCCH BCCH SYNC. CHLS. SYNC. CHLS. SB FB CCCH CCCH FACCH FACCH SACCH SACCH SCH SCH FCCH FCCH AB NB RACH RACH NB CBCH CBCH FB: Freq. Burst FB: Freq. Burst Uplink Uplink Downlink Downlink SB: Sync. Burst SB: Sync. Burst AB: Access Burst AB: Access Burst PCH/AGCH PCH/AGCH DB: Dummy Burst DB: Dummy Burst Downlink Downlink GGRajan
- 37. GSM Channels BCCH Broadcast Control Channel Parameters, LAI, CI, Neighbor Cells, Frequencies used in cell etc are transmitted to MS. FCCH (Frequency Correction Channel) BCCH- BCCH- FCCH transmits a constant frequency Downlink Only Downlink Only shift of the RF carrier that can be used NB/DB by the MS for frequency correction. BCCH SYNC. CHLS. BCCH SYNC. CHLS. SB FB SCH SCH SCH FCCH FCCH Synchronization Channel SCH is used to time synchronize the MSs, carries TDMA frame number and BSIC (Base Station Identity Code). GGRajan
- 38. GSM Channels CCCH Types RACH Used in uplink by MSs for requesting a channel for a connection. CCCH CCCH CBCH AB NB Used for the transmission of Short RACH RACH CBCH CBCH Messages as broadcast messages to Uplink Uplink Downlink Downlink all MSs. PCH PCH/AGCH PCH/AGCH Downlink Downlink Used in Down link by BTS to page IMSI, TMSI or IMEI to the MS. AGCH Used in downlink to allot DCCH, if MS requested via RACH. GGRajan
- 39. GSM Channels DCCH DCCH DCCH Dedicated Control CHannel SDCCH ACCH SDCCH ACCH Fully duplex, Point to Point channels. FACCH SACCH FACCH SACCH Used for signaling between BTS and a certain MS. Assigned to a single MS for call setup & subs. validation. DCCH, a single TS on an RF carrier used to convey 8 SDCCHs. SDCCH Stand-alone Dedicated Control Channel A duplex channel which is always allocated to a TCH or SDCCH. Used for transmission of signaling data, radio link supervision measurements, TX power control and timing advance data. GGRajan
- 40. GSM Channels ACCH ACCH ACCH Associated Control Channel Can be associated with either SDCCH or TCH. FACCH SACCH FACCH SACCH Used for carrying information associated with the process being carried out on either SDCCH or the TCH. SACCH Slow Associated Control CHannel Conveys power control & timing information in downlink. SACCH is used for non urgent procedures. FACCH Fast Associated Control Channel Used for handovers, assignments, for call set-up and release. GGRajan
- 41. GSM Frames TDMA Frame TDMA FRAME - 1 TDMA FRAME - 2 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 Time Slot BURST TIME SLOT – 0.577 ms GGRajan
- 42. GSM Frames TDMA Multi Frame 26-TDMA multi-frame Succession of 26 TDMA frames, and corresponds to the 26 x 8 BP or 120 ms. 51-TDMA multi-frame Succession of 51 TDMA frames, and corresponds to the 51 x 8 BP cycle. Superframe Sccession of 51 x 26 TDMA frames (6.12 sec). Hyperframe Numbering period, 2048 x 51 x 26 x 8 Broadcast Period long, or 3 hours, 28 minutes, 53 seconds and 760 milliseconds. GGRajan
- 43. GSM Frames Low Capacity Cell Combined BCCH / CCCH / DCCH 0 1 2 3 4 5 6 7 1 to 7 TRAFFIC GGRajan
- 44. GSM Frames Higher Capacity Cell Combined BCCH / CCCH 0 1 2 3 4 5 6 7 1 to 7 TRAFFIC DCCH 0 1 2 3 4 5 6 7 1 to 7 TRAFFIC GGRajan
- 45. GSM Frames 26 Frame Traffic Channel Multiframe 0 . 577 ms TIMESLOT TS-4 TDMA FRAME 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 4 . 615 ms MF0 ~ MF11 & MF13 ~ MF24 : Traffic : MF12 : SACCH : MF25 : Idle Idle 0 1 2 3 --- 12 -- 25 120 ms SACCH MULTIFRAME MS needs to send information about signal strength from surrounding cells to the network, Capacity required to send measurement info is 1/24 the capacity required to send voice. GGRajan
- 46. GSM Frames 51 Frame Control Channel Multiframe TS-4 0 . 577 ms TIMESLOT TDMA FRAME 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 4 . 615 ms IDLE 0 1 2 3 -- -- -- 12 --- -- 25 -- -- 49 50 MULTIFRAME 235.365 ms 51 Frame structure occurs in several forms, depending on the type of control channel and the network provider’s requirements GGRajan
- 47. GSM Frames Superframe & Hyperframe 0 1 2 3 4 5 6 7 4 . 615 ms TDMA Frame 26 Frames Multiframe 51 Frames Multiframe 0 1 2 -- --- -- -- 49 50 0 1 2 3 --- 12 -- 25 120 ms 235.65 ms Traffic Channel Control Channel Repeat 51 times Repeat 26 times 0 1 2 3 --- 12 -- 25 Superframe - 6 . 12 Sec - 1326 TDMA frames 0 25 50 2048 Superframes = 2715648 TDMA Frames 0 1 2 ---- Hyperframe ---- ----- 2046 2047 3 H 28 M 53 S 760 ms GGRajan
- 48. Mobile Originated Call MobileTerminated Call GSM Call Handover GGRajan
- 49. Mobile Call Phases Phasesof Mobile Originated Call / Setup phase. / Ringing phase. / Conversation phase. / Release phase. Phases of Mobile Terminated Call Routing analysis Paging. Call setup. Call release. GGRajan
- 50. GSM Call flow Base Station Subsystem BSC-1 Voice Call Switching Centre HLR VLR VLR MSC AUC AUC EIR EIR FIBER LINK BTS-1 NK LI W M BTS-2 BTS-1 BSC-2 PSTN BTS contains TX and RX BSC Manages Radio resources, Radio channels and Local connection management GGRajan
- 51. GSM Call flow Circuit-Switched Data Call Public Switched Telephone Network HLR MS MSC / BSC VLR BTS Wireless Network Internet IWF MS GGRajan
- 52. Handover Management Mobile Hand-off Signal Strength Handoff Zone B B T T S S Distance GGRajan
- 53. Handover Management Four types of handovers in GSM ..Channels (TS) in the same Cell Channels (TS) in the same Cell (Intra-BTS) (Intra-BTS) ..Cells under the control of same BSC Cells under the control of same BSC (Inter-BTS) (Inter-BTS) ..Cells under the control of different BSCs Cells under the control of different BSCs (Intra-MSC) (Intra-MSC) ..Cells under the control of different MSCs Cells under the control of different MSCs (Inter-MSC) (Inter-MSC) GGRajan
- 54. Handover Management MSC MSC BSC BSC BSC LAI-B LAI-A Inter MSC hand Off Intra BSC handoff Inter BSC hand Off GGRajan
- 55. Handover Management BSC MSCVLR BTS-A HLR BTS-B BSC MSC VLR •BSC-A informs MSC-A that MS needs handover from BTS-A to BTS-B •MSC-A informs MSC-B that a handover from BTS-A to BTS-B is underway •MSC-A commands BSC/BTS-A to proceed with handover to BTS-B. Hanover from BTS-A to BTS-B is underway •BTS-A commands MS to change to a specified channel on BTS-B •BTS-B informs BSC/MSC that hand over is complete • MSC-B informs the old MSC-A that hand over to BTS-B is complete GGRajan
- 56. General Packet RadioService (GPRS) Enhanced Data rate for GSM Evolution (EDGE) GGRajan
- 57. What is GPRS? / GPRS is a new bearer service for GSM / Packet Data Network (PDN) to the Internet. GPRS benefit from shorter access times and higher data rates. “online” over a long period of time, but billed for data volume. GPRS improves the utilization of the radio resources, Offers volume-based billing, Higher data transfer rates, Shorter access times, Simplifies the access to packet data networks. GPRS includes GSNs SGSN : Serving GPRS Support Node GGSN : Gateway GPRS Support Node GPRS Register GGRajan
- 58. GSM vs GPRS GPRS Architecture GSM Core BSC Network PSTN/ISP Air Interface Solution GPRS Core Network IP SGSN IP GGSN PDN Network Solution GGRajan
- 59. GPRS System Architecture GPRS in GSM Networks Packets Same Radio BSS for Packet and Circuit Traffic Circuit BSC IP GPRS GGSN PLMN SGSN MSC/VLR Intra PLMN IP HLR SS7 Backbone SGSN GGSN GSM PLMN X.25 MSC GGRajan
- 60. EDGE Features EDGE acts as a bolt-on enhancement to 2G and 2.5G, ie GPRS EDGE is also known as Enhanced GPRS, a superset to GPRS Can carry data speeds up to 384 Kbps in packet mode Meet the ITU's requirement for a 3G network EDGE requires no H/W changes in GSM core networks BSSs must be modified EDGE can be introduced in two ways : 1) Packet-switched enhancement (called EGPRS) 2) Circuit-switched data enhancement (called ECSD). GGRajan
- 61. GPRS - EDGEcompared Technical Differences - GPRS and EDGE Technology Data Rates Spectrum Services Voice and circuit data GSM/HSCSD 9.6 to 57.6 kbps 200 kHz services GPRS 171.6 kpbs 200 kHz Packet data services EDGE 473.6 kbps 200 kHz Packet data services GGRajan
- 62.