tài liệu giáo trình gms

tài liệu giáo trình gms tài liệu, giáo án, bài giảng , luận văn, luận án, đồ án, bài tập lớn về tất cả các lĩnh vực kinh...

04/2009 Overview 1. INTRODUCTION TO GSM 2. GSM ARCHITECTURE 3. GEOGRAPHICAL NETWORK ORGANIZATION 4. GSM NUMBERING 5. GSM CALLING (MOC, MTC) Overview 1. INTRODUCTION TO GSM a. What is GSM b. GSM services c. History d. GSM advantages and disadvantages What is GSM?  GSM (Global System for Mobile communication) is a Worldwide Digital Cellular Communications Network  formerly: Groupe Spéciale Mobile (founded 1982)  used in over 184 countries  The GSM network provides for  mobile voice communication  international roaming  mobile fax  text messaging  data services What is GSM?  GSM is a Second Generation (2G) digital radio cellular network  Time Division Multiplexing / Multiple access (TDM/TDMA) are employed  TDM / TDMA allows:  One frequency channel to be subdivided  Multiple conversations over a single physical channel GSM Subscriber Services Two basic types: 1. Telephony (Teleservices) Mainly voice services providing capability to communicate with other subscribers 2. Data (Bearer services) Capacity necessary to transmit appropriate data signals between two access points creating an interface to the network GSM Subscriber Services GSM supports the following subscriber services: 1. Dual tone multi frequency (DTMF) tone signaling scheme used for control purposes E.g. Remote control of an answering machine 2. Facsimile group III GSM supports CCITT group III Facsimile Special fax converter forms junction between standard analogue fax and GSM FAX GSM Subscriber Services 3. Short Message Services (SMS) Messaging facility consisting of maximum 160 alphanumeric characters to or from a mobile station to another 4. Cell Broadcast Variation of SMS where maximum number of alphanumeric characters is 93 Can be broadcast to users in a certain geographical area. E.g. Traffic congestion warnings GSM Subscriber Services 5. Voice Mail Answering machine within the network controlled by the subscriber Security code needed to access 6. Fax Mail Subscriber can receive fax messages at any fax machine 7. Emergency number common number mandatory for all service providers free of charge connection with the highest priority (pre-emption of other connections possible) GSM Supplementary Services  GSM supports comprehensive list of supplementary services supporting both data and voice services  The following compromises a partial list: 1. Call forwarding 2. Barring of outgoing calls 3. Advice of charge (AoC) [...]... Band Uplink: 890 MHz – 915 MHz / 1710 MHz – 1785 MHz Downlink: 935 MHz – 960 MHz / 1805 MHz – 1880 MHz Duplex distance 45MHz / 95MHz Carrier Separation 200 kHz Modulation Gaussian Minimum Shift Keying (GMSK) Transmission rate 270 kbit/s Access Method Time Division Multiple Access (TDMA) (narrow band) Speech coder Regular Pulse Excitation - Long Term Prediction (RPE-LPC) 13kbit/s Diversity Channel coding,... Controller BTS : Base Transceiver Station MS : Mobile Station PLMN : Public Land Mobile Network Radio Subsystem Radio Subsystem Components ISC : International Switching Center MSC : Mobile Switching Center GMSC : Gateway Mobile Switching Center HLR : Home Location Register VLR : Visitor Location Register PLMN : Public Land Mobile Network Network and Switching Subsystem NSS is the main component of the public