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Wireless Generations 1G, 2G & 3G Syed Azhar Hussain 99-CE-282

Wireless Generations 1G, 2G & 3G Syed Azhar Hussain 99-CE-282. Outline. Cellular Network Concept First Generation AMPS Second Generation Cellular Access Technologies FDMA, TDMA, CDMA GSM Third Generation UMTS. Cell Concept. Cell phone is basically a radio

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Wireless Generations 1G, 2G & 3G Syed Azhar Hussain 99-CE-282

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  1. Wireless Generations1G, 2G & 3GSyed Azhar Hussain99-CE-282

  2. Outline • Cellular Network Concept • First Generation • AMPS • Second Generation • Cellular Access Technologies • FDMA, TDMA, CDMA • GSM • Third Generation • UMTS

  3. Cell Concept • Cell phone is basically a radio • Combination of telephone (Alexander Graham Bell) and wireless communications (Guglielmo Marconi) • Originally used powerful radio telephones • Problems • Needed to be very powerful • Not many distinct frequencies (50) • Finally split cities into cells to allow cell reuse and reduce the required power – the cell concept • Each cell has a tower • About 800 frequencies across a cell • Size of cell is about 10 sq. miles

  4. Basics • Mobile: Any radio terminal that could be moved during operation or a radio • terminal that is attached to a high-speed mobile platform (e.g. a cellular • telephone in a fast moving vehicle) whereas the portable describes a radio • terminal that can be hand-held and used by someone at walking speed. • Subscriber: A mobile or portable user (user pay fee). • Subscriber Unit or Mobile Station: Each user communication device. • Mobiles or Users: Collective group of users in a wireless system. Many users • may actually user portable terminals. • Base Stations: A fixed stations in a mobile radio system used for • communication with mobile stations. They are located at the center or on the • edge of a coverage region and consist of radio channels and transmitter and • receiver antennas mounted on a tower. • Mobile Switching Center: Switching center, which coordinates the routing of • calls in large service area. In a cellular radio system, MSC connects cellular • base station and the mobiles to the PSTN. An MSC is also called a mobile • telephone switching office (MSTSO).

  5. Basics • Control Channel: Radio Channels used for transmission of call setup, call • request, call initiation and other beacon or control purpose. • Forward Channel: Transmission of information from the base to a mobile • station. • Reverse Channel: Transmission of information from the mobile to a base • station. • Roamer: A mobile station, which operates in a service area (market) other • than that from which service has been subscribe. • Handoff: The process of transferring a mobile station from one channel or • base station to another. • Page: A brief message, which is broadcast over the entire service area.

  6. Classification • Simplex: Communication is possible in only one direction (no acknowledge) e.g. Paging Systems. • Half duplex: Communication is bi directional but use same channel for both receiving and transmission (push-to-talk and release-to-listen). • Half duplex: Communication is bi directional but allows simultaneous transmission and reception b/w subscriber and base station. Implemented by FDD (frequency division duplex; separate channel) or TDD (time division duplex; adjacent time slots).

  7. PSTN (Public Switched Telephone Network) Generic WCS (Wireless Communication System) Base Station Base Station Switch Handset Handset

  8. Cellular Communications • Cells • Radio Tower Frequencies • Clusters • Frequency Reuse • Cell Splitting • Handoff PSTN

  9. Cellular Call Setup • 1. Phone scans for towers for strongest signal on control channel • 2.Transmit Mobile Identification Number (MIN), Electronic Serial Number (ESN), and telephone number • 3. MTSO sets up call PSTN Car Phone = 2W Cellular Service Subscriber Mobile Telephone Hand Phone = 0.7W Switching Office MTSO

  10. Wireless “Generations” First Generation (1989) • Analog voice using FM channels • Also called AMPS (Advanced Mobile Phone System) • Solved the issue of “mobility”

  11. Multiple Access The basis for any mobile system is its air interface design, and particularly the way the common transmission medium is shared between users, that is, multiple access scheme. Multiple access scheme defines how the radio spectrum is divided into channels, and how the channels separate the different users of the system. FDMA, TDMA, CDMA

  12. AMPS • AMPS – Advanced Mobile Phone System • Analog cell phone standard deployed across North America • Approved by FCC in 1983 – first deployed in Chicago • Utilizes 824MHz-894MHz frequencies • 832 available frequencies • 790 Voice • 42 Data (signaling) • 30 KHz wide – voice quality • FDMA • NAMPS – Narrowband AMPS – • 3x AMPS capacity

  13. Wireless “Generations” 2G - Second Generation (1998) • Digital modulation used for speech compression • Still a voice-only network, except for limited circuit switched data capability • Several different system types: • TDMA - time division multiple access • CDMA - code division multiple access • GSM - global mobile system (the original acronym is French) – Group Special Mobile. • Solved the issue of “capacity”

  14. Cellular Access Technologies • There are three common technologies used by cell phone networks for transmitting information: • Frequency Division Multiple Access (FDMA) • FDMA puts each call on a separate frequency. • Time Division Multiple Access (TDMA) • TDMA assigns each call a certain portion of time on a designated frequency. • Code Division Multiple Access (CDMA) • CDMA gives a unique code to each call and spreads it over the available frequencies. • The last part of each name is multiple access. This simply means that more than one user (multiple) can use (access) each cell.

  15. FDMA • In a FDMA system, the total system bandwidth is divided into several frequency channels that are allocated to users. 824.04 MHz 45 MHz 893.7 MHz

  16. TDMA • In a TDMA system, one frequency channel is divided into time slots that are allocated to users, and the users only transmit during their assigned timeslots. Examples of demand-assignment contention less protocols are token bus and token ring LANs described by the IEEE in the 802.4 and 802.5 standards. 6.7MS 824.04 MHz Digital decoding Digital encoding 893.7 MHz

  17. CDMA • CDMA takes an entirely different approach from TDMA. CDMA, after digitizing data, spreads it out over the entire bandwidth it has available. Multiple calls are overlaid over each other on the channel, with each assigned a unique sequence code. CDMA is a form of spread spectrum, which simply means that data is sent in small pieces over a number of the discrete frequencies available for use at any time in the specified range. 1850MHz Digital decoding Digital decoding 1990MHz CDMA

  18. GSM GSM – Groupe Spécial Mobile • GSM is an international digital cellular standard in Europe, Asia, Australia, and Africa • Originally, the acronym GSM stood for Groupe Spécial Mobile, a group formed by the Conference of European Posts and Telegraphs (CEPT) in 1982 to research the merits of a European standard for mobile telecommunications. • Commercial service using the GSM system did not actually start until 1991. • GSM was developed as a digital system using TDMA technology.

  19. GSM • GSM uses TDMA • 900 MHz – 1800 MHz (Europe and Asia) • 1900 MHz (North America) • Used for digital PCS services • One phone for all standard GSM worldwide except North America • To switch providers – switch SIM (subscriber identification modules) cards

  20. GSM Features • Uses encryption to make phone calls more secure • Data networking • Short Message Service (SMS) for text messages and paging • Call forwarding • Caller ID • Call waiting

  21. VLR HLR/ AuC BTS GSM Network Architecture BSS NSS Um MSC BSC TRAU A Abis Ater PSTN MS C MS – Mobile Station BSS – Base Station Subsystem BTS – Base Trans Station BSC – Base Station Controller TRAU - Transcoder / Rate Adaptation Unit MSC – Mobile Switching Centre NSS – Network Switching Subsystem VLR – Visitor Location Register HLR – Home Location Register AuC – Authentication Centre D

  22. Evolving Standards and Terminology • 1st Generation • AMPS • Bell Wireless Alliance • Cantel • 2nd Generation • IS-95A (CDMA) and IS-136 (TDMA) • Bell Wireless Alliance(CDMA) • ATT Rogers (Cantel)(TDMA) • Clearnet (CDMA) • Microcell (GSM)

  23. Wireless “Generations” 2.5 Generation • Packet switched data at rates up to 144 kbps • Several different types: • GPRS - evolved from GSM • 1xRTT - evolved from CDMA • Will require a Core IP Network • Solves the issue of “mobility” with packet data

  24. GPRS GPRS – General Packet Radio Services • An evolution of GSM • Higher speed data services • GPRS has seamless interface capabilities to TCP/IP

  25. MSC Um PSTN TRAU BSC VLR A Abis Ater C MS HLR/ AuC D Agprs GGSN Gr Frame Relay Backbone Gb Private IP Backbone BTS Gn Gn Gb SGSN PCU Gi External Packet Networks Intranet, Internet From GSM to GSM/GPRS Network MS – Mobile Station BSS – Base Station Subsystem BTS – Base Trans Station BSC – Base Station Controller TRAU - Transcoder / Rate Adaptation Unit MSC – Mobile Switching Centre NSS – Network Switching Subsystem VLR – Visitor Location Register HLR – Home Location Register AuC – Authentication Centre\ SGSN – Serving GPRS Support Node GGSN – Gateway GPRS Support Node

  26. Research in Motion • GPRS in Canada/US • BlackBerry

  27. Wireless “Generations” 3G -Third Generation (future) • Packet switched data at rates up to 2.4 Mbps • ITU standard - standards still evolving • Adds the high data rate component and quality of service parameters • Introduces an Open Standard concept that will foster increased development of wireless applications, much like the Internet.

  28. UMTS Universal Mobile Telecommunications System • Third Generation (3G) Technology • Uses W-CDMA, FDD, TDD • Phase 1, called Release 1999 (R99) is an evolution of the GSM network architecture • Key features: • Open standards based • all IP in the core • decentralized network • service based • In plain English : a network that will allow IP devices to roam while providing 384 kbps to 2 Mbps access rates. • If successful, may become the “World Standard”

  29. UMTS • Will provide 2 Mbps in a local environment • Will provide 384 kbps at highway velocities • Will use IP over ATM to control different data types: • controlling data latency and quality • Will use W-CDMA-FDD for macro mobility at 144 kbps • Will use W-CDMA-TDD for micro mobility at 2 Mbps

  30. ATM Backbone Node B (BTS) Node B (BTS) ATM Backbone UMTS Architecture • UMTS Terrestrial Radio Access Network (UTRAN) Core Network Access Network RNC - Radio Network Controller Uu Iu (CS & PS) Iub(ATM) Circuit Domain UE Iur Uu Iur Packet Domain Iu (CS & PS) Iub (ATM) UE RNC

  31. PSTN ATM Backbone GGSN Private IP Backbone Node B (BTS) Node B (BTS) SGSN External Packet Networks UMTS Interfaces Access Network Core Network Uu MSC TRAU RNC Iu CS Iu (CS & PS) Iub(ATM) UE C Iur VLR D ATM Backbone HLR/AuC Gr Uu Iur Iu PS Iu (CS & PS) Iub(ATM) Gn Gn UE Gi RNC

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