1.2_E1_E2_CM_2022_GSM_intro_Architecture.pptx

E1_E2_CM_2022_GSM_intro_Architecture.pptx

1. E1 – E2 (CM) – Core Paper (2022) GSM – Introduction and Architecture For Internal Circulation Within BSNL Only

2. GSM - Introduction GSM stands for Global System for Mobile Communication. GSM is a 2nd Generation Digital Cellular Communication System. GSM is the most widely accepted standard in telecommunications and it is implemented globally. GSM is the name of a standardization group established in 1982 to create a common European mobile telephone standard but it has been rapidly accepted worldwide. GSM is a circuit-switched system that divides each 200 kHz channel into eight 25 kHz time-slots. For Internal Circulation Within BSNL Only

3. GSM – Introduction – Contd ….. GSM operates on the mobile communication bands 900 MHz and 1800 MHz in most parts of the world. In the US, GSM operates in the bands 850 MHz and 1900 MHz GSM makes use of narrowband Time Division Multiple Access (TDMA) technique for transmitting signals. GSM was developed using digital technology. It has an ability to carry 64 kbps to 120 Mbps of data rates. GSM provides basic to advanced voice and data services including roaming service. Roaming is the ability to use your GSM phone number in another GSM network. For Internal Circulation Within BSNL Only

4. GSM RADIO INTERFACE Frequency band 900 Mhz Uplink 890 MHz-915 MHz Downlink 935 MHz-960MHz Duplex distance 45MHz Carrier separation 200KHz Modulation GMSK Air transmission rate 270Kbps Access method FDMA/TDMA For Internal Circulation Within BSNL Only

5. Uplink & Downlink B T S UPLINK DOWNLINK For Internal Circulation Within BSNL Only

6. 890 MHz 915 MHz 935 MHz 960 MHz Uplink Downlink Example: Channel 48 124 channel # 124 channel # Frequency Frequency Duplex spacing = 45 MHz Frequency band spectrum = 2 x 25 MHz Channel spacing = 200 kHz BTS Paired Radio Channels in GSM Case of GSM 900 For Internal Circulation Within BSNL Only

7. ARFCN - Absolute Radio Frequency Channel Number For Internal Circulation Within BSNL Only

8. 1800MHz 1900MHz 900MHz Single Band Dual Band Triple Band In a sense, the network determines the handsets can be selected.But nowadays, most handsets support dual band. Frequency Resource For Internal Circulation Within BSNL Only

9. GSM - SUMMARY Standard or primary GSM 900 Band 1800 band Uplink frequency 890-915 MHz 1710 - 1785 MHz Downlink frequency 935-960 MHz 1805 – 1880MHz Duplex Distance 45 MHz 95 MHz Carrier separation 200 KHz 200 KHz Frequency Channels 124 (+1) 374 (+1) Voice coder bit rate 13 Kbps 13 Kbps Modulation GMSK GMSK Air transmission Rate 270.8333 Kbps 270.8333 Kbps Access Method FDMA/TDMA FDMA/TDMA Speech Coder RPE-LTP RPE-LTP Duplexing FDD FDD For Internal Circulation Within BSNL Only

10. Bandwidth and Duplexing Spacing For Internal Circulation Within BSNL Only

11. Challenge: Need of Simultaneous Communication in both direction Solution : Duplexing Methodology Duplexing is the technique by which the send and receive paths are separated over the medium, since transmission entities (modulator, amplifiers, demodulators) are involved. There are two types of Duplexing . • Frequency Division Duplexing FDD • Time Division Duplexing TDD For Internal Circulation Within BSNL Only

12. Frequency Division Duplexing FDD Different Frequencies are used for send and receive paths and hence there will be a forward band and reverse band. Duplexer is needed if simultaneous transmission (send) and reception (receive) methodology is adopted. Frequency separation between forward band and reverse band is constant Downlink Uplink For Internal Circulation Within BSNL Only

13. Time Division Duplexing (TDD) TDD uses different time slots for transmission and reception paths. Single radio frequency can be used in both the directions instead of two as in FDD. Hence No duplexer is required. Only a fast switching synthesizer, RF filter path and fast antenna switch are needed. It increases the battery life of mobile phones. For Internal Circulation Within BSNL Only

14. Architecture of GSM Network For Internal Circulation Within BSNL Only

15. GSM – Network Areas For Internal Circulation Within BSNL Only

16. International Mobile Equipment Identity [IMEI] The IMEI is used for equipment identification. Am IMEI uniquely identifies a mobile station as a piece or assembly of equipment. IMEI = TAC + FAC + SNR + SP TAC= Type Approval Code (6 digits), determined by GSM body FAC= Final Assembly Code (2 digits), identifies the manufacturer SNR= Serial Number (6 digits), uniquely identifying all equipment within each TAC and FAC SP = Spare for future use (1 digit) For Internal Circulation Within BSNL Only

17. International Mobile Subscriber Identity [IMSI] Subscriber always identified within the GSM network by the IMSI This is used for all signaling in the PLMN stored in SIM and HLR/VLR The IMSI consists of three different parts MCC = Mobile Country Code(3 Digits) MNC = Mobile Network Code(2 Digits) MSIN = Mobile Station Identification Number ( Upto 10 digits) For Internal Circulation Within BSNL Only

18. Mobile Station International Subscriber Directory Number -MSISDN The MSISDN is a GSM directory number which uniquely identifies a mobile subscription in the Public Switched Telephone Network (PSTN). Calls will be routed from the PSTN and other networks based on the Mobile Subscribers’ MSISDN number. MSISDN= CC + NDC + SN CC= Country Code (91) NDC= National Destination Code(98370) SN= Subscriber Number (12345) For Internal Circulation Within BSNL Only

19. Mobile Station Roaming Number [ MSRN] HLR knows in what Service area the subscriber is located. In order to provide a temporary number to be used for routing, the HLR requests the current MSC/VLR to allocate a Mobile Station Roaming Number(MSRN) to the called subscriber and to return it. At reception of the MSRN, HLR sends it to the MSC, which now can route the call to the VLR where the called subscriber is currently registered. For Internal Circulation Within BSNL Only

20. Temporary Mobile Subscriber Identity [TMSI] The TMSI is used for the subscriber’s confidentiality. It should be combined with the LAI to uniquely identify a MS. Since the TMSI has only local significance (that is, within the MSC/VLR area), the structure may be chosen by each administration. The TMSI should not consist of more than four octets. For Internal Circulation Within BSNL Only

21. Location Area Identity (LAI) LAI identifies a location area which is a group of cells.. It is transmitted in the BCCH. When the MS moves into another LA (detected by monitoring LAI transmitted on the BCCH) it must perform a LU. LAI = MCC + MNC + LAC MCC= Mobile Country Code(3 digits), identifies the country MNC= Mobile Network Code(1-2 digits), identifies the GSM-PLMN LAC= Location Area Code, identifies a location area within a GSM PLMN network. The maximum length of LAC is 16 bits,enabling 65536 different location areas to be defined in one GSM PLMN. For Internal Circulation Within BSNL Only

22. Cell Identifier (CI) Cell Identifier (CI) (maximum 2 × 8) bits, Individual cells that are within an LA can be recognized. When the Global Cell Identity (LAI + CI) calls are combined, then it is uniquely defined. For Internal Circulation Within BSNL Only

23. Local Mobile Subscriber Identity (LMSI) LMSI is an original key, assigned by the VLR An LMSI is assigned if the mobile station is registered with the VLR and sent to the HLR. LMSI comprises of four octets (4x8 bits). For Internal Circulation Within BSNL Only

24. Thank YOU For Internal Circulation Within BSNL Only