中国科学技术大学 个人通信与扩频实验室 邱玲，赵明 助教：董逸天

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1 中国科学技术大学 个人通信与扩频实验室 邱玲，赵明 助教：董逸天
移动通信原理 Reference: Theodore S. Rappaport, Wireless Communications Principles and Practice, Second Edition 中国科学技术大学 个人通信与扩频实验室 邱玲，赵明 助教：董逸天

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3 Contents 1. Introduction 2. Modern Wireless Systems
3. Cellular Concept 4. Mobile Radio Propagation: Large-Scale Path Loss 5. Mobile Radio Propagation: Small-Scale fading and multipath 6. Mobile Modulation Techniques 7. Equalization, Diversity, and channel coding 8. Speech coding 9. Multiple Access Techniques 10. Wireless Networking 11. Wireless Systems and Standards

4 Chapter Introduction

5 Contents 1.1 Evolution of Wireless Communication
1.2 Wireless Communication Systems 1.2.1 Cellular Systems 1.2.2 Cordless Telephone 1.2.3 Wireless Access (WLL & W-LAN) 1.2.4 Satellite Systems 1.3 Concept of Mobile System 1.3.1 Basic Concept Call Process

6 1.1 Evolution of Wireless Communication
Evolution of Mobile Radio Communications 1897年马可尼发明无线电 上世纪二十年代至四十年代初期：移动通信的早期发展阶段 1921年美国底特律警察移动通信系统，1926年西德列车移动电话系统 上世纪四十年代中期至六十年代初期：公用移动通信业务开始问世 1946年美国贝尔“城市系统”，1950（西德）、1956（法国）、1959（英国），50年代中期，美国贝尔系统完成了人工交换系统 上世纪六十年代中期至七十年代中期：移动电话系统的改进和完善阶段 美国的IMTS和西德的B网路：直接拨号、自动选择无线频道并自动接入公用电话网 上世纪七十年代中期以后：无线通信开始进入新时代 用于无线通信的高可靠、小型化的晶体射频硬件的出现，无线设备朝小型化和功能多样化方面发展；另一方面，开始了公用移动通信系统新体制的论证与实验

7 A little bit of wireless history
Maxwell’s Equation published in 1865

8 It predicted the existence of electromagnetic wave!
A solution to the Maxwell’s Equation It predicted the existence of electromagnetic wave!

9 All in the family!

10 Experiments of Hertz Hertz’s experiment to generate microwave in 1888
Validated Maxwell’s prediction

11 Experiments of Hertz

12 Experiments of Hertz (cont.)
A simple schematic Feasibility of microwave communication demonstrated

13 The Big Step Forward from Marconi
Transmitted telegraph signals in 1890 at his home Wireless telegraph between ships and shore in 1897 Trans-Atlantic communication in Dec 14, 1901 from Poldhu, Cornwall (UK) to St John’s, Newfoundland, (Is the earth round?) From

14 The Big Step Forward from Marconi (cont.)
The letter “S” (Morse code …) was transmitted from a 25,000 W station Jan 18, 1903, wireless telegram and a reply LONDON  ENGLAND  IN TAKING ADVANTAGE OF THE WONDERFUL TRIUMPH OF SCIENTIFIC RESEARCH AND INGENUITY WHICH HAS BEEN ACHIEVED IN PERFECTING A SYSTEM OF WIRELESS TELEGRAPHY I EXTEND ON BEHALF OF THE AMERICAN MOST CORDIAL GREETINGS AND GOOD WISHES TO YOU AND TO ALL THE PEOPLE OF THE BRITISH EMPIRE       THEODORE ROOSEVELT  WELLFLEET MASS JAN

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16 1.2 Wireless Communication Systems
Cellular Systems Cordless Telephone Wireless Access Systems Paging System Satellite Systems

17 Cellular Systems

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20 First generation mobile communication --- 1G Analog System
basic technical feature: analog technology analog circuit units Cellular structure, roaming, handover Second generation mobile communication G Digital system digital technology digital process units SIM card, light handset, high capacity Third generation mobile communication G Smart system intelligent process technology smart process units Multimedia, higher capacity, intelligent network

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22 4G LTE-Release8/9: OFDM, MIMO, with a total of 32 million users
(August 2012) and expectations of close to two billion users in 2018. LTE-A-Release10, finalized in 2010, the possibility for transmission bandwidth beyond 20 MHz carrier aggregation, enhanced multi-antenna transmission, and the introduction of relaying functionality. R11 Dec. 2012, In addition to further refining some of the features introduced as part of Rel-10, CoMP, enhanced support for heterogeneous deployments, advanced terminal receivers and for multistandard base stations supporting. R12 June-Sept. 2014, not only increased capacity and enhanced end-user experience, Enhanced local area access, Multi-antenna enhancements, Improved support for machine-type communication (MTC), Direct device-to-device communication 5G:系统数据业务支撑能力达10Gbps，频谱及功率效率较4G提升10倍，网络覆盖的单位面积吞吐率较4G提升25倍。

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24 Cordless Telephone

25 1.2.3 Wireless Access Systems ---- Wireless Local Loop
S-CDMA PHS IEEE 802.XX

26 Paging Systems

27 To provide ultra-reliable coverage
Paging transmitters are located on tall buildings Small RF bandwidths (to which the noise level is proportional) are used to maximize SNR of each paging receiver Low data rates are used(6400bps)

28 1.2.5 Satellite Systems Properties Disadventages Seamless coverage
Large coverage area Long distance Reliable communication link Large bandwidth Large capacity Disadventages Large delay (270ms，100ms)

29 System composing Space part Ground part terminal Types Synchronous Asynchronous: middle orbit, ellipse orbit, low orbit Applications Navigation (Position, transportation…) Digital film Satellite radio, Satellite remote sensing

30 1.3 Concept of Mobile Systems
1.3.1 Basic Concept 1.3.2 Call Processing

31 1.3.1 Basic Concept Cellular Structure

32 Simplex Multiple access MS – BS – BSC – MSC Link Roaming, Handover

33 Some Definitions

34 Call Process How a Cellular Telephone Call is Made

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36 作业： 1. 列举常见的无线通信系统。    2. 为什么寻呼系统需要提供较低的数据传输速率？较低的数据速率如何实现更好的覆盖？ 3. 列举主要的第二代至第四代蜂窝网络标准。 4. 假设蜂窝电话使用容量为1安培小时的电池。假设蜂窝电话在空闲时耗电35mA，通话时耗电250mA。如果用户一直开机，并且每天通话3分钟，那么这个电池能用多久？每天通话6小时呢？该电池最多能通话多久。