Ch1 Introduction to Wireless Communications & Networks Reading materials: [1]Overview of wireless communications [2] 移动通讯词汇（中英）

Outline  Part 1 Introduction to Wireless Communication & Networks  Part 2 Applications of Wireless Networks

Part 1 Introduction to Wireless Communication & Networks The Wireless Vision Technical Challenges Current Wireless Systems Emerging Wireless Systems Spectrum Regulation Standards

Wireless History First Mobile Radio Telephone 1924

Pre-Cellular Wireless One highly-elevated antenna in a large service area Small number of channels Very low capacity Examples: MJ and MK systems in the United States

The Cellular Concept Basic Principles Frequency Reuse Cell Splitting First proposed by D. H. Ring at Bell Laboratories in 1947

Cellular - Implementation

Cellular Systems: Reuse channels to maximize capacity Geographic region divided into cells Frequencies/timeslots/codes reused at spatially-separated locations. Co-channel interference between same color cells. Base stations/MTSOs coordinate handoff and control functions Shrinking cell size increases capacity, as well as networking burden BASE STATION MTSO

GSM System Architecture

Cellular Phone Networks BS MTSO PSTN MTSO BS San Francisco New York Internet

The Wireless Revolution Cellular is the fastest growing sector of communication industry (exponential growth since 1982, with over 2 billion users worldwide today) Three generations of wireless First Generation (1G): Analog 25 or 30 KHz FM, voice only, mostly vehicular communication Second Generation (2G): Narrowband TDMA and CDMA, voice and low bit-rate data, portable units. 2.5G increased data transmission capabilities Third Generation (3G): Wideband TDMA and CDMA, voice and high bit-rate data, portable units

World Telecom Statistics Crossover has happened in May 2002!

World Cellular Subscribers by Technology as of June Billion Cellular Customers Worldwide GSM/UMTS Totals 82.3%

World Cellular Subscriber Distribution as of June 2006

GSM Growth to June 2006

Exciting Developments Internet and laptop use exploding 2G/3G wireless LANs growing rapidly Huge cell phone popularity worldwide Emerging systems such as Bluetooth, UWB, Zigbee, and WiMAX opening new doors Military and security wireless needs Important interdisciplinary applications

Future Wireless Networks Wireless Internet access Nth generation Cellular Wireless Ad Hoc Networks Sensor Networks Wireless Entertainment Smart Homes/Spaces Automated Highways All this and more… Ubiquitous Communication Among People and Devices Hard Delay Constraints Hard Energy Constraints

Design Challenges Wireless channels are a difficult and capacity- limited broadcast communications medium Traffic patterns, user locations, and network conditions are constantly changing Traffic is nonstationary, both in space and in time Energy and delay constraints change design principles across all layers of the protocol stack

Evolution of Current Systems Wireless systems today 2G Cellular: ~30-70 Kbps. WLANs: ~10 Mbps. Next Generation 3G Cellular: ~300 Kbps. WLANs: ~70 Mbps. Technology Enhancements Hardware: Better batteries. Better circuits/processors. Link: Antennas, modulation, coding, adaptivity, DSP, BW. Network: Dynamic resource allocation. Mobility support.

Migration to 3G

3G: ITU-Developed IMT-2000 Satellite Macrocell Microcell Urban In-Building Picocell Global Suburban Basic Terminal PDA Terminal Audio/Visual Terminal

Future Generations Rate Mobility 2G3G4G b WLAN 2G Cellular Other Tradeoffs: Rate vs. Coverage Rate vs. Delay Rate vs. Cost Rate vs. Energy Fundamental Design Breakthroughs Needed

Gap between the data rate speed of cellular and WLAN

25 Wireless Access: Range of Operation of Different Techniques

Current Wireless Systems Cellular Systems Wireless LANs Satellite Systems Paging Systems Bluetooth Ultrawideband radios Zigbee radios

Cellular Systems － 1G

Cellular Systems － 2G

Cellular Systems 2G － D-AMPS

Cellular Systems 2G － GSM

Cellular Systems 2G － CDMA

Cellular Systems--2.5G

Cellular Systems--3G

Cellular Systems 3G—IMT-2000

Cellular Systems 3G—UMTS

Subscriber Growth

37 Fourth Generation of Mobile Telecommunications

Cellular Systems 3GPP 3GPP(LTE, Long Term Evolution ) and 3GPP2 are currently developing evolutionary revolutionary systems beyond 3G.

什么是 LTE ？ 3GPP(The 3rd Generation Partnership Project) 是一个组织：组织伙伴，市 场代表伙伴和个体会员。 TD- SCDMA 3G3G LTE （ 2004 ） Num. txt WCDMA CDMA2000 LTE Advanced---- 4G （ 2008 ） LTE （ Long Term Evolution ，长期演进 ) 革命 演进

演进路线 合久必分分久比合 铁塔公司 + 虚拟运营商 3GPP IEEE 移动带宽化 带宽移动化 LTE

Cellular Systems--4G

Cellular Systems--4G( 续 )

43 5th Generation Wireless System

WLAN

Wireless Local Area Networks (WLANs) WLANs connect “local” computers (100m range) Breaks data into packets Channel access is shared (random access) Backbone Internet provides best-effort service Poor performance in some apps (e.g. video) Internet Access Point

Wireless LAN Standards b (Current Generation) Standard for 2.4GHz ISM band (80 MHz) Frequency hopped spread spectrum Mbps, 500 ft range a (Emerging Generation) Standard for 5GHz NII band (300 MHz) OFDM with time division Mbps, variable range Similar to HiperLAN in Europe g (New Standard) Standard in 2.4 GHz and 5 GHz bands OFDM Speeds up to 54 Mbps In 200?, all WLAN cards will have all 3 standards

WPAN

Satellite Systems Cover very large areas Different orbit heights GEOs (39000 Km) versus LEOs (2000 Km) Optimized for one-way transmission Radio (XM, DAB) and movie (SatTV) broadcasting Most two-way systems struggling or bankrupt Expensive alternative to terrestrial system A few ambitious systems on the horizon

Inmarsat Satellite MARITIME LAND AERO NCS TT&C RESCUE COORDINATION CENTRE OCC SCC Inmarsat NOC LES National & International Telecom Network voice fax data telex Inmarsat System ( 海事卫星 )

How the Inmarsat System Works The satellites are controlled from the Satellite Control Centre (SCC) at Inmarsat HQ in London. Four tracking, telemetry and control (TT&C) stations located at Fucino, Italy; Beijing in China; Lake Cowichan, western Canada; and Pennant Point, eastern Canada. There are also back-up stations at Eik in Norway and Aukland, New Zealand. A call from an Inmarsat mobile terminal goes directly to the satellite overhead, which routes it back down to a land earth station (LES). The flow of communications traffic through the Inmarsat network is monitored and managed by the Network Operations Centre (NOC) at Inmarsat HQ. The NOC is supported by network co-ordination stations (NCS).

Inmarsat 卫星覆盖图

车载卫星导航系统

中国卫星概况 1970 年 4 月 24 日，第一颗人造卫星 “ 东方红一号 ” 发射成功，使中国成为世界上第五个独立研制 和发射人造地球卫星的国家 1975 年 11 月 26 日，首次发射回收了返回式遥感卫 星 使中国成为世界上第三个掌握卫星返回技术 的国家 1984 年 4 月 8 日发射成功第一颗 “ 东方红二号 ” 地球 静止轨道通信卫星 4 月 16 日定点于东经 125 赤道 上空，使中国成为世界上第五个独立研制和发 射静止轨道卫星的国家

中国卫星系列 返回式遥感卫星系列 “ 东方红 ” 通信广播卫星系列 “ 风云 ” 气象卫星系列 “ 实践 ” 科学探测与技术试验卫星系列 “ 资源 ” 地球资源卫星系列 “ 北斗 ” 导航定位卫星系列

Paging Systems Broad coverage for short messaging Message broadcast from all base stations Simple terminals Optimized for 1-way transmission Answer-back hard Overtaken by cellular

8C Cimini-7/98 Bluetooth Cable replacement RF technology (low cost) Short range (10m, extendable to 100m) 2.4 GHz band (crowded) 1 Data (700 Kbps) and 3 voice channels Widely supported by telecommunications, PC, and consumer electronics companies Few applications beyond cable replacement

Ultrawideband Radio (UWB) UWB is an impulse radio: sends pulses of tens of picoseconds( ) to nanoseconds (10 -9 ) Duty cycle of only a fraction of a percent A carrier is not necessarily needed Uses a lot of bandwidth (GHz) Low probability of detection Excellent ranging capability Multipath highly resolvable: good and bad Can use OFDM to get around multipath problem.

Why is UWB Interesting? Unique Location and Positioning properties 1 cm accuracy possible Low Power CMOS transmitters 100 times lower than Bluetooth for same range/data rate Very high data rates possible 500 Mbps at ~10 feet under current regulations 7.5 Ghz of “free spectrum” in the U.S. FCC recently legalized UWB for commercial use Spectrum allocation overlays existing users, but its allowed power level is very low to minimize interference “Moore’s Law Radio” Data rate scales with the shorter pulse widths made possible with ever faster CMOS circuits

IEEE / ZigBee Radios Low-Rate WPAN Data rates of 20, 40, 250 kbps Star clusters or peer-to-peer operation Support for low latency devices CSMA-CA channel access Very low power consumption Frequency of operation in ISM bands Focus is primarily on radio and access techniques

Data rate 10 kbits/sec 100 kbits/sec 1 Mbit/sec 10 Mbit/sec 100 Mbit/sec 0 GHz2 GHz1GHz3 GHz5 GHz4 GHz6 GHz a UWB ZigBee Bluetooth ZigBee b g 3G UWB

Range 1 m 10 m 100 m 1 km 10 km 0 GHz2 GHz1GHz3 GHz5 GHz4 GHz6 GHz a UWB ZigBee Bluetooth ZigBee b,g 3G UWB

Power Dissipation 1 mW 10 mW 100 mW 1 W 10 W 0 GHz2 GHz1GHz3 GHz5 GHz4 GHz6 GHz a UWB ZigBee Bluetooth ZigBee bg 3G

Emerging Systems Ad hoc wireless networks Sensor networks Distributed control networks

Ad-Hoc Networks Peer-to-peer communications. No backbone infrastructure. Routing can be multihop. Topology is dynamic. Fully connected with different link SINRs

Design Issues Ad-hoc networks provide a flexible network infrastructure for many emerging applications. The capacity of such networks is generally unknown. Transmission, access, and routing strategies for ad-hoc networks are generally ad-hoc. Crosslayer design critical and very challenging. Energy constraints impose interesting design tradeoffs for communication and networking.

Sensor Networks Energy is the driving constraint Nodes powered by nonrechargeable batteries Data flows to centralized location. Low per-node rates but up to 100,000 nodes. Data highly correlated in time and space. Nodes can cooperate in transmission, reception, compression, and signal processing.

Energy-Constrained Nodes Each node can only send a finite number of bits. Transmit energy minimized by maximizing bit time Circuit energy consumption increases with bit time Introduces a delay versus energy tradeoff for each bit Short-range networks must consider transmit, circuit, and processing energy. Sophisticated techniques not necessarily energy-efficient. Sleep modes save energy but complicate networking. Changes everything about the network design: Bit allocation must be optimized across all protocols. Delay vs. throughput vs. node/network lifetime tradeoffs. Optimization of node cooperation.

Spectrum Regulation Spectral Allocation in US controlled by FCC (commercial) or OSM (defense) FCC auctions spectral blocks for set applications. Some spectrum set aside for universal use Worldwide spectrum controlled by ITU-R Regulation can stunt innovation, cause economic disasters, and delay system rollout

Standards Interacting systems require standardization Companies want their systems adopted as standard Alternatively try for de-facto standards Standards determined by TIA/CTIA in US IEEE standards often adopted Process fraught with inefficiencies and conflicts Worldwide standards determined by ITU-T In Europe, ETSI is equivalent of IEEE

Main Points The wireless vision encompasses many exciting systems and applications Technical challenges transcend across all layers of the system design. Cross-layer design emerging as a key theme in wireless. Existing and emerging systems provide excellent quality for certain applications but poor interoperability. Standards and spectral allocation heavily impact the evolution of wireless technology

72 Layer Architecture in Wireless Networks Physical layer Transmission over the propagation channels Modulations, coding/decoding, interferences, multiplexing etc. Link layer Radio resource management such as power control, rate control, and error control. Network resource management such as call admission control and service scheduling Networking layer Handoff management Location management Traffic management

73 Influence of Mobile Communication to the Layer Model service location new applications, multimedia adaptive applications congestion and flow control quality of service addressing, routing, device location hand-over authentication media access multiplexing media access control encryption modulation interference attenuation Frequency Application layer Transport layer Network layer Data link layer Physical layer

74 Effects of Portability Power consumption Limited computing power, low quality displays, small disks due to limited battery capacity l CPU: power consumption l Transceiver power consumption Loss of data Higher probability, has to be included in advance into the design (e.g., defects, theft) Limited user interfaces compromise between size of fingers and portability integration of character/voice recognition, abstract symbols Limited memory limited value of mass memories with moving parts flash-memory as alternative

Some Acronyms in this lecture OFDM: Orthogonal Frequency Division Multiplexing DAB: Digital Audio Broadcasting UAV: Unmanned Aerial Vehicle OSM: Office of Spectrum Management FCC: Federal Communications Commission TIA: Telecommunications Industry Association CTIA: Cellular Telecommunications Industry Association ISM: Industrial, Scientific, and Medical ETSI: European Telecommunications Standards Institute EDGE: Enhanced Data services for GSM Evolution HDR: High Data Rate DSP: Digital Signal Processing SINR: Signal-to-Interference-plus-Noise Ratio

Part 2 Applications of Wireless Networks 概况 美国 欧洲 亚洲 重要厂商

概况 -- 无线通信网络的发展

2011 年中国手机用户概况 用户总数已达 9 亿 2010 年 3.03 亿用户使用手机上网，较 2009 年增加 了 2.3 亿。 2010 年新增 3G 用户数 3.47 亿， 2011 年第 1 季度新 增 3G 用户数 1.35 亿 2010 年购买智能手机 6200 万部，预计 2011 年购买 智能手机 9500 万部

移动智能终端发展态势

概况 -- 无线网络应用

概况 -- 无线网络应用现状

概况 -- 无线热点

美国现状

美国星巴克

欧洲现状

欧洲 —“The Cloud”

欧洲 —“MAGNET”

亚洲现状

重要厂商 -Cisco

重要厂商 -Intel

重要厂商 -Intel( 续 )

重要厂商 -Microsoft

重要厂商 -IBM

重要厂商 - 手机厂商

重要厂商 - 宠物服务 (1)

重要厂商 - 宠物服务 (2)

重要厂商 - 宠物服务 (3) “PetsCell” ，兼容现有的蜂窝网络和卫星 GPS 技 术。 能够让宠物的主人与他们的宠物讲话，以及在 必要时请求别人提供帮助。 如果宠物走失，有人发现这个宠物在大街上徘 徊，按一下宠物身上佩带的设备，自动拨号功 能就可以把电话打到宠物主人的家里，让主人 找回宠物。

智能手机市场概况 (1)

智能手机市场概况 (2)

Mobile Internet

微信 微信（英文名： wechat ）是腾讯公司于 2011 年 1 月 21 日推出的一个为智能终端提供即时通讯服 务的免费应用程序，微信支持跨通信运营商、 跨操作系统平台通过网络快速发送免费（需消 耗少量网络流量）语音短信、视频、图片和文 字，同时，也可以使用通过共享流媒体内容的 资料和基于位置的社交插件 “ 摇一摇 ” 、 “ 漂流瓶 ” 、 “ 朋友圈 ” 、 ” 公众平台 “ 、 ” 语音记事本 “ 等服务 插件。

二. 微信的特点 1. 基本功能：聊天，添加好友，实时对讲机 功能 2. 微信支付 3. 其他功能：朋友圈，语音提醒，通讯录安 全助手等

大道至简 过渡页