Eos Chap2


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Eos Chap2

  1. 1. EH417 임베디드운영체제<br />이동통신 기술 개요<br />Page 1<br />
  2. 2. 목차<br />Basics & Technology Evolution<br />Architecture and Functionality (GSM, 3G and beyond)<br />Cellular future goals (2010 and beyond)<br />Convergence<br />Comparison with Internet<br />Page 2<br />
  3. 3. 기본 구성<br />Multiple Access<br />Downlink<br />Handoff<br />Uplink<br />Base Station<br />Fixed transceiver<br />Mobile Station<br />Distributed transceivers<br />Cells<br />Different Frequencies or Codes<br />Page 3<br />
  4. 4. 다중 채널 서비스 방식<br />Frequency<br />CMDA: Code Division Multiple Access<br />TDMA: Time Division Multiple Access <br />FDMA: Frequency Division Multiple Access <br />Codes<br />Time<br />Page 4<br />
  5. 5. Cellular Technology Evolution<br />0G: Mobile radio telephones (PTT, MTS) <br />1G: Analog <br />2G/3G and beyond - digital:<br />cdmaOne/CDMA2000 Family<br />GSM Family<br />GSM<br />cdmaOne/IS-95<br />GPRS<br />2G<br />EDGE<br />HSCSD<br />WCDMA (UMTS)<br />CDMA2000 EV-DO<br />3G<br />HSPA<br />Page 5<br />
  6. 6. 목차<br />Basics & Technology Evolution<br />Architecture and Functionality (GSM, 3G and beyond)<br />Cellular future goals (2010 and beyond)<br />Convergence<br />Comparison with Internet<br />Page 6<br />
  7. 7. Global System for Mobile communications (GSM)<br />900/1800 MHz band (US: 850/1900 MHz)<br />For 900 MHz band<br />Uplink: 890-915 <br />Downlink: 935-960<br />25 MHz bandwidth - 124 carrier frequency channels, spaced 200KHz apart<br />Time Division Multiplexing for 8 full rate speech channels per frequency channel.<br />Circuit Switched Data with data rate of 9.6 kbps <br />Handset transmission power limited to 2W in GSM850/900 and 1W in GSM1800/1900. <br />Page 7<br />
  8. 8. Architecture<br />Page 8<br />
  9. 9. The Base Station Subsystem (BSS)<br />Base Transceiver Station (BTS) - transceivers serve different frequencies. <br />Frequency hopping by handsets and transceivers<br />Sectorization using directional antennas <br />Base Station Controller (BSC) controls several (tens to hundreds) of BTSs <br />allocation of radio channels<br />handovers between BTSs <br />concentrator of traffic <br />databases with information such as carrier frequencies, frequency hopping lists, power reduction levels, etc. for each cell site<br />Page 9<br />
  10. 10. Network Switching Subsystem (NSS)<br />GSM circuit-switched core network manages communication between mobile phones & PSTN<br />Mobile Switching Center (MSC) : provides circuit switched calling, mobility management, GSM services for users<br />Gateway MSC – interfaces with PSTN, determines which visited MSC the subscriber being called is currently located at<br />Visited MSC - MSC where a customer is currently located. The Visitor Location Register (VLR) associated with this MSC has subscriber's data. <br />Anchor MSC - MSC from which handover initiated. <br />Target MSC- MSC toward which a handover should take place. <br />Page 10<br />
  11. 11. GPRS core network<br />Mobility management, session management, and transport for IP services<br />GPRS Tunneling Protocol, GTP (over UDP) allows end users mobility with continued Internet connectivity<br />GPRS support nodes (GSN) <br />GGSN - Gateway GPRS Support Node <br />SGSN - Serving GPRS Support Node <br />Page 11<br />
  12. 12. GSM Support for Data Services: GPRS<br />User gets pair of uplink and downlink frequencies. <br />Multiple users share the same frequency channel with time domain multiplexing. <br />Packets have constant length corresponding to a GSM time slot. <br />Downlink uses FCFS packet scheduling <br />Uplink <br />Slotted ALOHA for reservation inquiries during contention phase<br />data transferred using dynamic TDMA with FCFS scheduling. <br />Upto 64 kbps (more for EDGE) downlink per user. <br />Page 12<br />
  13. 13. UMTS and 3G technologies (WCDMA & HSPA)<br />Universal Mobile Telecommunications System (UMTS) - WCDMA as the underlying interface<br />Supports up to 14 Mbps rates with HSDPA (typical present deployed rates per user 384kbps)<br />Frequency bands <br />1885-2025 Mhz (uplink), 2110-2200 Mhz (downlink)<br />US: 1710-1755 MHz and 2110-2155 MHz <br />W-CDMA has 5 Mhz wide radio channels (CDMA2000 transmits on one or several pairs of 1.25 Mhz radio channels).<br />HSDPA allows networks based on UMTS to have higher data rates (1.8. 3.6, 7.2, 14.4 Mbps via AMC, and HARQ, fast packet scheduling.<br />UMTS air interface forms Generic Radio Access Network (GeRAN) which can be connected to various backbone networks like the Internet, ISDN, GSM or UMTS. <br />Using PCMCIA or USB card, or cellular router customers are able to access 3G broadband services <br />Page 13<br />
  14. 14. Cellular Evolution<br /><ul><li>WCDMA Evolution (source: SKT)</li></ul>HSDPA: High-Speed Downlink Packet Access <br />HSUPA: High-Speed Uplink Packet Access <br />Page 14<br />
  15. 15. Cellular Evolution<br /><ul><li>Service Evolution</li></ul>Page 15<br />
  16. 16. 1G<br />( Analog )<br />2G<br />( Digital )<br />3G<br />( IMT2000 )<br />3G+<br />(HSDPA, HSUPA)<br />Mobile Communication Roadmap<br />Mobility<br />1995<br />2000<br />2005<br />2010+<br />4 G<br />High<br />Speed<br />WiBro<br />802.16e<br />CDMA2000 EV-DO/DV<br /> W-CDMA/HSDPA<br />Medium<br />Speed<br />CDMA/GSM/TDMA<br />RFID<br />High speed<br />WLAN<br />WPAN<br />ZigBee<br />MANet<br />5 GHz <br />WLAN<br />Wi-Max<br />802.11a/g<br />AMPS<br />ETACS<br />JTACS<br />NMT<br />Low<br />Speed<br />2.4 GHz<br />WLAN<br />Bluetooth<br />802.11b<br />PAN<br />Data <br />Rates<br /><1 Mbps<br /><100 Mbps<br />~ 14.4 kbps<br /><10 Mbps<br />144 kbps<br />384 kbps<br />Page 16<br />
  17. 17. 목차<br />Basics & Technology Evolution<br />Architecture and Functionality (GSM, 3G and beyond)<br />Cellular future goals (2010 and beyond)<br />Convergence<br />Comparison with Internet<br />Page 17<br />
  18. 18. 2010년 이후 전망*<br />Next Generation Mobile Networks (NGMN) Ltd. - Consortium with partnership of major mobile operators<br />Recommendations without specific technology prescriptions<br />Target to establish performance targets, recommendations and deployment scenarios for future wide-area mobile broadband network packet switched core<br />The architecture intended to provide a smooth migration of existing 2G/3G networks towards an IP network that is cost competitive and has broadband performance.<br /> The result is 3GPP LTE<br />Page 18<br />* 주) 2005년 전망 자료임<br />
  19. 19. NGMN: Beyond 3G<br />Video telephony and multimedia conferencing, IM, video streaming – among high drivers for NGMN<br />Essential System recommendations<br />Seamless mobility across all bearers with service continuity through a min of 120 km/h<br />Peak uplink data rates 30-50 Mbps<br />Peak > 100Mbps downlink<br />Latency core < 10ms, RAN <10ms, <30ms e2e<br />QoS based global roaming<br />Broadcast, multicast, and unicast services to subscribers of all environments<br />Real time, conversational and streaming in PS across all required bearers<br />Cost per MB : as close to DSL as possible <br />Page 19<br />
  20. 20. NGMN Envisioned System Architecture<br />Page 20<br />
  21. 21. 목차<br />Basics & Technology Evolution<br />Architecture and Functionality (GSM, 3G and beyond)<br />Cellular future goals (2010 and beyond)<br />Convergence<br />Comparison with Internet<br />Page 21<br />
  22. 22. Convergence<br />Heterogeneous access technologies<br />Multi-mode access devices <br />Dual mode phones (WiFi, 2.5/3G), UMA<br />Heterogeneous Services<br />Cellular Internet access and Internet based voice/video access<br />Challenges<br />Time variant heterogeneous network characteristics<br />Heterogeneous applications with different utilities<br />System design and networking challenges<br />Page 22<br />
  23. 23. 목차<br />Basics & Technology Evolution<br />Architecture and Functionality (GSM, 3G and beyond)<br />Cellular future goals (2010 and beyond)<br />Convergence<br />Comparison with Internet<br />Page 23<br />
  24. 24. Cellular Networks and Internet<br />Circuit Switched Analog<br />Circuit Switched Digital<br />C.S. Voice + P.S. Data<br />Internet<br />Cellular Networks<br />기본 서비스<br />Data<br />Voice<br />Packet Switched<br />Technology<br />Controlled<br />Evolution<br />Semi-Organic<br />Operator initiated or partnered<br />Third party/ independent (largely)<br />New Services<br />Mobility Support<br />Good<br />Poor<br />Page 24<br />
  25. 25. Cellular Networks and Internet<br />Internet<br />Cellular Networks<br />QoS at edges<br />Good Support (voice vs. data)<br />Mostly absent<br />Data rates for supporting broadband services<br />Insufficient as of present<br />Relatively high<br />Cost per MB of data<br />Lower<br />Higher<br />Page 25<br />