Tài liệu Mobile & wireless networking – lecture 6 cellular systems umts lte 2 - geert heijenk

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262001 Mobile & Wireless Networking Lecture 6: Cellular Systems (UMTS / LTE) (2/2) & Other systems [Reader, Part 5] [Optional: Schiller, Section 4.2, 4.3, 5, 6] Geert Heijenk Mobile and Wireless Networking 2009 / 2010 Outline of Lecture 6   Cellular Systems (UMTS / LTE) (2/2)         UMTS High Speed Downlink Packet Access (HSDPA) UMTS High Speed Uplink Packet Access (HSUPA) Long Term Evolution Other systems         IEEE 802.16 WiMAX DECT TETRA Satellite Systems 2 Mobile and Wireless Networking 2009 / 2010 HSDPA (The downlink) Main improvements:     MAC-layer: from RNC to base station Improved radio: higher order modulation initially 16-QAM, newer releases 64 QAM Techniques used:       Fast Adaptive Modulation & Coding Fast Channel-Dependent Scheduling Fast Hybrid ARQ Result:         increases throughput (→14.4 Mbps) reduces latency increases data capacity newer releases promise throughputs up to 86.4 Mbps (with MIMO, 64-QAM, and multiple carriers (dual-cell)) Introduction:   2006 (in NL, max 7.2 Mbps) 3 Mobile and Wireless Networking 2009 / 2010 Fast Channel-Dependent Scheduling Schedule a packet for transmission to a certain user when it has a “good” channel •  Increases throughput •  May decrease fairness between users  trade-off 4 Mobile and Wireless Networking 2009 / 2010 HSUPA (the enhanced uplink) Main improvements:   MAC-layer: from RNC to base station (as HSDPA)   no higher order modulation Techniques used:     Fast Channel-Dependent Scheduling Fast Hybrid ARQ Result:         increases throughput (→5.76 Mbps) reduces latency increases data capacity newer releases promise throughputs up to 23 Mbps (with higher order modulation, and multiple carriers (dual-cell)) Introduction:   2008 (in NL, max 2 Mbps) 5 Mobile and Wireless Networking 2009 / 2010 GSM / UMTS Coverage (2009) 6 Mobile and Wireless Networking 2009 / 2010 Long Term Evolution: Background •  Evolution of 3G UMTS radio access technology Supporting (only) (IP) packet-based services •  Targets: •  •  •  •  •  •  •  Increased data rates (100 Mbit/s, 50 Mbit/s) Increased capacity (3 – 4 x Rel. 6 (HSDPA)) Improved spectrum efficiency (x3) Reduced latency: <10 ms RTT, <100ms channel setup, Reduced cost Spectrum flexibility 7 Mobile and Wireless Networking 2009 / 2010 LTE Characteristics •  Flexible channel bandwidth: •  •  Duplexing: •  •  multiple parallel stop-and-wait, with soft combining / incremental redundancy Max Data Rates: •  •  up to 4x4 in downlink, or multi-user MIMO (down-/uplink) Hybrid ARQ: •  •  Single Carrier FDMA (OFDMA with extra Discrete Fourier Transform) MIMO: •  •  OFDMA Uplink: •  •  FDD, TDD, and combined FDD/TDD (half duplex) Downlink: •  •  1.4, 3, 5, 10, 15, 20 MHz 75 Mbit/s (uplink), 300 Mbit/s (downlink, with MIMO) New core network: •  Evolved Packet Core 8 Mobile and Wireless Networking 2009 / 2010 Duplexing in LTE 9 Mobile and Wireless Networking 2009 / 2010 OFDMA vs SC-FDMA OFDMA SC-FDMA 180 15 kHz 10 Mobile and Wireless Networking 2009 / 2010 Evolved Packet Core 11 Mobile and Wireless Networking 2009 / 2010 Outline of Lecture 6   Cellular Systems (UMTS / LTE) (2/2)         UMTS High Speed Downlink Packet Access (HSDPA) UMTS High Speed Uplink Packet Access (HSUPA) Long Term Evolution Other systems         IEEE 802.16 WiMAX DECT TETRA Satellite Systems 12 Mobile and Wireless Networking 2009 / 2010 IEEE 802.16 / WiMAX   WiMAX: Worldwide Interoperability for Microwave Access   Fixed WiMAX     Mobile WiMAX     targeted at fixed wireless Similar market as UMTS with HSDPA / HSUPA Standards:   IEEE 802.16-2004: Fixed WiMAX     Based on 2001 standard: a, b, c, and d amendments IEEE 802.16-2009: Mobile WiMAX     Includes 2005 extensions for mobility, and newer extensions MAC Modifications for limited mobility: handover & low power operations 13 Mobile and Wireless Networking 2009 / 2010 WiMAX overview of techniques               Orthogonal Frequency Division Multiple Access (OFDMA) Flexible (scalable) number of sub-carriers (up to 2048) Adaptive Modulation Smart Antenna possible (e.g., MIMO: multiple input, multiple output) Fast Scheduling (for both uplink and downlink) Hybrid ARQ Fast Channel Feedback 14 Mobile and Wireless Networking 2009 / 2010 WiMAX OFDMA Frame Structure Source: Mobile WiMAX - Part I: A Technical Overview and Performance Evaluation, WiMAX Forum  A sub-channel is a group of 48 sub-carriers  Frame duration is 5 ms (symbol time ~ 0.1 ms) 15 Mobile and Wireless Networking 2009 / 2010 Outline of Lecture 6   Cellular Systems (UMTS / LTE) (2/2)         UMTS High Speed Downlink Packet Access (HSDPA) UMTS High Speed Uplink Packet Access (HSUPA) Long Term Evolution Other systems         IEEE 802.16 WiMAX DECT TETRA Satellite Systems 16 Mobile and Wireless Networking 2009 / 2010 Digital Enhanced Cordless Telecommunication (DECT)   DECT (Digital European Cordless Telephone) standardized by ETSI for cordless telephones, renamed for international marketing reasons into „Digital Enhanced Cordless Telecommunication“   standard describes air interface between base-station and mobile phone Characteristics                 frequency: 1880-1990 MHz channels: 120 full duplex duplex mechanism: TDD (Time Division Duplex) with 10 ms frame length multiplexing scheme: FDMA with 10 carrier frequencies, TDMA with 2x 12 slots modulation: digital, Gaußian Minimum Shift Key (GMSK) power: 10 mW average (max. 250 mW) range: approx. 50 m in buildings, 300 m open space 17 Mobile and Wireless Networking 2009 / 2010 DECT Dynamic Channel Allocation       periodically (< 30s) measure RSSI on all frequency/timeslot combinations keep list of combinations with least RSSI for setting up new channels listen to channels with high RSSI to see what is strongest basestation 18 Mobile and Wireless Networking 2009 / 2010 Outline of Lecture 6   Cellular Systems (UMTS / LTE) (2/2)         UMTS High Speed Downlink Packet Access (HSDPA) UMTS High Speed Uplink Packet Access (HSUPA) Long Term Evolution Other systems         IEEE 802.16 WiMAX DECT TETRA Satellite Systems 19 Mobile and Wireless Networking 2009 / 2010 Trunked Radio Systems           many different radio carriers assign single carrier for a short period to one user/group of users police, ambulance, rescue teams, taxi service, fleet management interfaces to public networks, voice and data services very reliable, fast call setup, local operation 20 Mobile and Wireless Networking 2009 / 2010
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