1 / 17

GSM

GSM. BY, Murali Iyengar +91 9894 3247 10. GSM. INTRODUCTION GSM FACTS GOALS OF GSM SERVICES & FEATURES SYSTEM ARCHITECTURE CHANNEL TYPES FRAME STRUCTURE SIGNAL PROCESSING. Murali Iyengar +91 9894 3247 10. INTRODUCTION.

nadda
Download Presentation

GSM

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. GSM BY, Murali Iyengar +91 9894 3247 10

  2. GSM • INTRODUCTION • GSM FACTS • GOALS OF GSM • SERVICES & FEATURES • SYSTEM ARCHITECTURE • CHANNEL TYPES • FRAME STRUCTURE • SIGNAL PROCESSING Murali Iyengar +91 9894 3247 10

  3. INTRODUCTION • GSM:- ESTI standard for 2G pan- European digital cellular with international roaming. • Developed to solve the fragmentation problem of first cellular system. • First introduced in European market in 1991. Murali Iyengar

  4. GSM FACTS - Used in over 170 countries - Over 400 GSM network operators - Over 550 million People Were subscribers to GSM TDMA pdk GSM 550 million CDMA 90 million Murali Iyengar

  5. GOALS OF GSM • Improved spectrum efficiency • High quality speech • International roaming • Low cost mobile set & base station • Support for new services • Compatibility with ISDN & other telephone company services Murali Iyengar

  6. SERVICES User services : # Telephone services - emergency calling & facsimile. # Bearer services or data services – packet switched protocols data rates from 300bps to 9.6kbps. # Supplementary ISDN services – call diversion , caller identification SMS Murali Iyengar

  7. FEATURES • SIM:-Memory device stores information( subscriber’s identification no. , networks , countries) • On air privacy :- made possible by encrypting the digital bit stream sent by GSM transmitter Murali Iyengar

  8. SYSTEMARCHITECTURE Consist of three major parts: # base transceiver station # base station controller # the transcoder & adaptation unit Murali Iyengar

  9. SYSTEM ARCHITECTURE HLR VLR AUC PSTN BSC MSC ISDN BSC DATA OMC NETWORK SWITCHING SUBSYSTEM PUBLIC NETWORK BASE STATION SUBSYSTEM

  10. BASE TRANSRECIVERSTATION • Serves a single cell • Usually placed in center of a cell • Coding • Crypting • Multiplexing • Modulating • synchronizing Murali Iyengar

  11. BASE STATION CONTROLLER BTS BSC • Translates the 13 kbps voice • Frequency hopping • Time and frequency • Power management • Time delay measurement To MSC 2 mbps Abis

  12. TRANSCODER & ADAPTATION UNIT • (13 kbps speech or data + 3 kbps additional synchronizing data) *4 = 64 kbps (TRAU) standard rate BSD 64 kbps TRAU MSC Murali Iyengar

  13. The various interfaces used in GSM MS BTS BTS BSC MSC PSTN MS SS7 BTS A interface (standardized) GSM radio air interface Abis interface Murali Iyengar

  14. FRAME STRUCTURE 6.12 SUPERFRAME 51 MULTIFRAME Murali Iyengar 120 MULTI FRAME 26 FRAME 4.615 8 TIME SLOTS FRAME 5 0 1 2 4 6 3 7 576.92 TM 1 3 57 1 26 57 3 8.25

  15. SIGNAL PROCESSING • Speech coding • Channel coding for data channels • Channel coding for control channels • Interleaving • Ciphering Murali Iyengar

  16. GSM operationsfrom speechinput to speech output Digitizing & source coding Source decoding Channelcoding Channel decoding SPEECH SPEECH interleaving De- interleaving Burstformatting Burst formatting ciphering De- ciphering Radio channel demodulation modulation

  17. CONCLUSION Murali Iyengar +91 9894 3247 10

More Related