OFDM for Wireless Communications Systems(Universal Personal Communications Series)

by Ramjee Prasad

Overview

OFDM (Orthogonal Frequency Division Multiplexing) is a key technology which allows for robust, high capacity, high speed wireless broadband multimedia networks. Written by leading authority and best-selling author Ramjee Prasad, this timely new work offers today's wireless professionals a complete understanding of OFDM technology and applications in wireless communications systems, placing emphasis on wireless LANs (local area networks) and PANs (personal area networks). The book offers an in-depth treatment of the underlying technologies and applications of PANs and describes and evaluates a practical OFDM system concept. Invaluable for wireless engineers and researchers, this cutting edge new book is a must-have for anyone who needs to understand this critical technology and its implementation in today's wireless systems.

Product Details

ISBN-13:	9781580537964
Publisher:	Artech House, Incorporated
Publication date:	09/28/2004
Series:	Artech House Universal Personal Communications Library
Pages:	292
Product dimensions:	7.00(w) x 10.00(h) x 0.69(d)

Table of Contents

	Preface	xiii
	Acknowledgments	xv
Chapter 1	Introduction	1
1.1	Wireless Technology in the Future	1
1.1.1	WWANs	3
1.1.2	WLANs	4
1.1.3	WPANs	5
1.1.4	WB-PANs	6
1.1.5	The Next Generation	7
1.2	Orthogonal Frequency-Division Multiplexing	11
1.2.1	History of OFDM	11
1.3	Concluding Remarks	14
	References	16
Chapter 2	WLANs	19
2.1	Introduction	19
2.1.1	WLANs in a Nutshell	21
2.1.2	IEEE 802.11, HIPERLAN/2, and MMAC WLAN Standards	23
2.2	MAC in WLAN Standards	27
2.2.1	IEEE 802.11	27
2.2.2	HIPERLAN/2	31
2.3	QoS over WLANs	33
2.3.1	IEEE 802.11e	33
2.3.2	Interframe Spacing	35
2.3.3	Other QoS-Related Developments	36
2.4	Security in IEEE 802.11	36
2.4.1	Current IEEE 802.11	36
2.4.2	IEEE 802.11i and IEEE 802.11f	39
	References	43
Appendix 2A	ISM Bands	46
Appendix 2B	Comparison of WLAN and WPAN Standards	47
Chapter 3	WPANs	49
3.1	Introduction	49
3.1.1	Emergence of Personal Area Networking (The Person-Centered Concept)	49
3.2	Technical Challenges of a WPAN Technology	54
3.2.1	Ad Hoc Connectivity	55
3.2.2	Service Discovery and Resource Selection	56
3.3	Enabling Technologies	57
3.3.1	Comparison of Short-Range Wireless Technologies	60
3.4	Ongoing Research	60
3.4.1	Architecture and Middleware Issues	60
3.5	Research Issues for Future WPAN Technology	73
	References	76
Chapter 4	Appropriate Channel Model for OFDM Systems	83
4.1	Introduction	83
4.2	Characterization of the Mobile Radio Channel	84
4.2.1	Components of a Multipath Channel Model	84
4.2.2	Definitions	85
4.2.3	Variation of Channel Parameters Due to Bandwidth Limitation	90
4.3	FD Channel Modeling	90
4.3.1	The WSSUS Channel Model	91
4.3.2	Channel Description	94
4.3.3	Relation to (Physical) Channel Parameters	95
4.4	FD Channel Simulation	97
4.4.1	Model Description	98
4.4.2	Implementation of the Simulation Scheme	99
4.4.3	FD Simulation Results	100
4.4.4	Differences from Time-Domain Simulation Schemes	104
4.5	Application to Millimeter-Wave Radio Channels	104
4.5.1	Discussion of Measurement Results	105
4.5.2	Discussion of Channel Parameters	106
4.5.3	Overview of Channel Models	110
4.5.4	Applicability of the FD Model	111
4.6	Conclusions	112
	References	114
Chapter 5	Basics of OFDM and Synchronization	117
5.1	Introduction	117
5.2	OFDM Introduction and System Model	117
5.2.1	OFDM Introduction and Block Diagram	118
5.2.2	Design of the OFDM Signal	120
5.2.3	OFDM System Model	123
5.2.4	Synchronization Errors	128
5.3	Performance of an Uncoded OFDM System	133
5.3.1	Mathematical Modeling	133
5.3.2	Analytical Evaluation of the BER	134
5.3.3	Performance Results	141
5.4	Conclusions and Recommendations	144
	References	146
Chapter 6	The Peak Power Problem	149
6.1	Introduction	149
6.2	Distribution of the PAP Ratio	150
6.3	Clipping and Peak Windowing	152
6.3.1	Required Backoff with a Nonideal Power Amplifier	155
6.3.2	Coding and Scrambling	158
6.4	Peak Cancellation	160
6.5	PAP Reduction Codes	166
6.5.1	Generating Complementary Codes	167
6.5.2	Minimum Distance of Complementary Codes	171
6.5.3	Maximum-Likelihood Decoding of Complementary Codes	172
6.5.4	Suboptimal Decoding of Complementary Codes	174
6.5.5	Large Code Lengths	177
6.6	Symbol Scrambling	177
	References	180
Chapter 7	A Novel Hybrid OFDM Concept	183
7.1	Introduction	183
7.2	Detailed Structure of Various Multiple-Access Schemes	184
7.2.1	Overview of Various Modulation Schemes	184
7.2.2	DS-CDMA	187
7.2.3	SFH Interface	188
7.2.4	OFDM/CDMA/SFH System Description	191
7.2.5	Summary	197
7.3	Comparison to MC-CDMA	197
7.3.1	Background	198
7.3.2	Basic Principles of MC-CDMA	198
7.3.3	The Hybrid System	201
7.3.4	Comments on the MC-CDMA Technique	202
7.3.5	Summary	205
7.4	Analytical Performance in Fading Channels and Simulation in AWGN Channels	206
7.4.1	Comparison of DS-CDMA and DS-CDMA-SFH (DS-SFH) Systems	206
7.4.2	Noncoherent Class of Signals (DS-CDMA)	206
7.4.3	DS-CDMA-SFH	208
7.4.4	Coherent Class of Signals	211
7.4.5	OFDM-CDMA-SFH (Hybrid)	211
7.4.6	Simulations	213
7.4.7	Summary	214
7.5	Performance in Fading Channels with Perfect Estimation	215
7.5.1	FD Modeling	215
7.5.2	Analytical Evaluation of the BER	216
7.5.3	Coherent Detection with Perfect Channel Estimation	218
7.5.4	Calculation of the Parameters	219
7.5.5	Simulations with Perfect Channel Estimation	220
7.5.6	Summary	229
7.6	Performance in Fading Channels with Realistic Estimation	229
7.6.1	Baseband Model	230
7.6.2	Channel Estimation with TDP Method	231
7.6.3	Simulated OFDM System Parameters	235
7.6.4	Simulation Results for QPSK/16-QAM	235
7.6.5	Summary	237
7.7	Conclusions	239
	References	239
Chapter 8	A Practical OFDM System: Fixed Broadband Wireless Access (FBWA)	243
8.1	Introduction	243
8.2	Motivation	243
8.2.1	Cell-Based Infrastructure	244
8.2.2	Mesh Topology-Based Infrastructure	245
8.3	Proposed FBWA	245
8.4	Systems Requirements	248
8.4.1	Parameter Selection	249
8.4.2	Communications Protocol	249
8.4.3	Duplex Schemes	250
8.4.4	Downlink Transmission	250
8.4.5	Uplink Transmission	252
8.4.6	Frame Structure	253
8.4.7	MAC Consideration and Conformance	254
8.4.8	Adaptability of the Proposed Kernel Architecture to BWAS	256
8.4.9	Summary	256
8.5	Ubiquitous Connectivity	256
	References	258
	About the Author	261
	Index	263