Cover image for Smart antennas
Title:
Smart antennas
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Publication Information:
Boca Raton : CRC Press, 2004
ISBN:
9780849312069
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30000010081829 TK7871.67.A33 G 64 2004 Open Access Book Book
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Summary

Summary

The use of smart antennas to increase mobile communications channels has re-ignited research and development in the field. Practicing engineers are eager to discover more about this subject, and need a comprehensive book that can provide a learning platform and prevent the loss of time spent on searches through journal literature.

Smart Antennas examines nearly all aspects of array signal processing and presents them in a logical manner. It delivers a detailed treatment of antenna array processing schemes, adaptive algorithms to adjust weighting, direction of arrival (DOA) estimation methods, diversity-combining methods that combat fading and reduce errors.

The book introduces the various processor structures suitable for the narrowband field, examining the behavior of both element space and beamspace processors. It then explores adaptive processing, focusing on the simple matrix inversion algorithm, constrained least mean squares (LMS), the neural network approach, and more. The text also describes smart antennas that are suitable for broadband signals, and presents analyses and techniques suitable for correlated fields in narrowband and broadband signals.

This volume supplements its content with extensive references, enabling you to further investigate smart antenna array schemes and application.


Table of Contents

1 Introductionp. 1
1.1 Antenna Gainp. 1
1.2 Phased Array Antennap. 2
1.3 Power Patternp. 2
1.4 Beam Steeringp. 2
1.5 Degree of Freedomp. 3
1.6 Optimal Antennap. 4
1.7 Adaptive Antennap. 4
1.8 Smart Antennap. 4
1.9 Book Outlinep. 5
Referencesp. 6
2 Narrowband Processingp. 7
2.1 Signal Modelp. 11
2.1.1 Steering Vector Representationp. 14
2.1.2 Eigenvalue Decompositionp. 17
2.2 Conventional Beamformerp. 18
2.2.1 Source in Look Directionp. 19
2.2.2 Directional Interferencep. 20
2.2.3 Random Noise Environmentp. 23
2.2.4 Signal-to-Noise Ratiop. 23
2.3 Null Steering Beamformerp. 25
2.4 Optimal Beamformerp. 26
2.4.1 Unconstrained Beamformerp. 27
2.4.2 Constrained Beamformerp. 28
2.4.3 Output Signal-to-Noise Ratio and Array Gainp. 30
2.4.4 Special Case 1: Uncorrelated Noise Onlyp. 31
2.4.5 Special Case 2: One Directional Interferencep. 32
2.5 Optimization Using Reference Signalp. 33
2.6 Beam Space Processingp. 36
2.6.1 Optimal Beam Space Processorp. 38
2.6.2 Generalized Side-Lobe Cancelerp. 41
2.6.3 Postbeamformer Interference Cancelerp. 44
2.6.4 Comparison of Postbeamformer Interference Canceler with Element Space Processorp. 60
2.6.5 Comparison in Presence of Look Direction Errorsp. 61
2.7 Effect of Errorsp. 67
2.7.1 Weight Vector Errorsp. 68
2.7.2 Steering Vector Errorsp. 71
2.7.3 Phase Shifter Errorsp. 81
2.7.4 Phase Quantization Errorsp. 88
2.7.5 Other Errorsp. 89
2.7.6 Robust Beamformingp. 90
Notation and Abbreviationsp. 90
Referencesp. 94
3 Adaptive Processingp. 101
3.1 Sample Matrix Inversion Algorithmp. 103
3.2 Unconstrained Least Mean Squares Algorithmp. 104
3.2.1 Gradient Estimatep. 105
3.2.2 Covariance of Gradientp. 105
3.2.3 Convergence of Weight Vectorp. 107
3.2.4 Convergence Speedp. 110
3.2.5 Weight Covariance Matrixp. 112
3.2.6 Transient Behavior of Weight Covariance Matrixp. 114
3.2.7 Excess Mean Square Errorp. 116
3.2.8 Misadjustmentp. 118
3.3 Normalized Least Mean Squares Algorithmp. 120
3.4 Constrained Least Mean Squares Algorithmp. 120
3.4.1 Gradient Estimatep. 122
3.4.2 Covariance of Gradientp. 122
3.4.3 Convergence of Weight Vectorp. 123
3.4.4 Weight Covariance Matrixp. 124
3.4.5 Transient Behavior of Weight Covariance Matrixp. 125
3.4.6 Convergence of Weight Covariance Matrixp. 127
3.4.7 Misadjustmentp. 128
3.5 Perturbation Algorithmsp. 130
3.5.1 Time Multiplex Sequencep. 131
3.5.2 Single-Receiver Systemp. 132
3.5.3 Dual-Receiver Systemp. 134
3.5.4 Covariance of Weightsp. 135
3.5.5 Misadjustment Resultsp. 138
3.6 Structured Gradient Algorithmp. 139
3.6.1 Gradient Estimatep. 140
3.6.2 Examples and Discussionp. 141
3.7 Recursive Least Mean Squares Algorithmp. 143
3.7.1 Gradient Estimatesp. 144
3.7.2 Covariance of Gradientp. 145
3.7.3 Discussionp. 147
3.8 Improved Least Mean Squares Algorithmp. 147
3.9 Recursive Least Squares Algorithmp. 150
3.10 Constant Modulus Algorithmp. 152
3.11 Conjugate Gradient Methodp. 153
3.12 Neural Network Approachp. 154
3.13 Adaptive Beam Space Processingp. 156
3.13.1 Gradient Estimatep. 157
3.13.2 Convergence of Weightsp. 158
3.13.3 Covariance of Weightsp. 158
3.13.4 Transient Behavior of Weight Covariancep. 159
3.13.5 Steady-State Behavior of Weight Covariancep. 160
3.13.6 Misadjustmentp. 161
3.13.7 Examples and Discussionp. 162
3.14 Signal Sensitivity of Constrained Least Mean Squares Algorithmp. 163
3.15 Implementation Issuesp. 166
3.15.1 Finite Precision Arithmeticp. 166
3.15.2 Real vs. Complex Implementationp. 167
Notation and Abbreviationsp. 174
Referencesp. 178
Appendicesp. 182
4 Broadband Processingp. 201
4.1 Tapped-Delay Line Structurep. 203
4.1.1 Descriptionp. 203
4.1.2 Frequency Responsep. 206
4.1.3 Optimizationp. 207
4.1.4 Adaptive Algorithmp. 209
4.1.5 Minimum Mean Square Error Designp. 212
4.2 Partitioned Realizationp. 216
4.2.1 Generalized Side-Lobe Cancelerp. 218
4.2.2 Constrained Partitioned Realizationp. 222
4.2.3 General Constrained Partitioned Realizationp. 223
4.3 Derivative Constrained Processorp. 225
4.3.1 First-Order Derivative Constraintsp. 225
4.3.2 Second-Order Derivative Constraintsp. 228
4.3.3 Optimization with Derivative Constraintsp. 228
4.3.4 Adaptive Algorithmp. 234
4.3.5 Choice of Originp. 234
4.4 Correlation Constrained Processorp. 236
4.5 Digital Beamformingp. 237
4.6 Frequency Domain Processingp. 240
4.6.1 Descriptionp. 241
4.6.2 Relationship with Tapped-Delay Line Structure Processingp. 243
4.6.3 Transformation of Constraintsp. 248
4.7 Broadband Processing Using Discrete Fourier Transform Methodp. 252
4.7.1 Weight Estimationp. 254
4.7.2 Performance Comparisonp. 255
4.7.3 Computational Requirement Comparisonp. 259
4.7.4 Schemes to Reduce Computationp. 260
4.7.5 Discussionp. 265
4.8 Performancep. 267
Notation and Abbreviationsp. 267
Referencesp. 271
5 Correlated Fieldsp. 275
5.1 Correlated Signal Modelp. 276
5.2 Optimal Element Space Processorp. 278
5.3 Optimized Postbeamformer Interference Canceler Processorp. 280
5.4 Signal-to-Noise Ratio Performancep. 283
5.4.1 Zero Uncorrelated Noisep. 286
5.4.2 Strong Interference and Large Number of Elementsp. 287
5.4.3 Coherent Sourcesp. 287
5.4.4 Examples and Discussionp. 288
5.5 Methods to Alleviate Correlation Effectsp. 289
5.6 Spatial Smoothing Methodp. 292
5.6.1 Decorrelation Analysisp. 293
5.6.2 Adaptive Algorithmp. 296
5.7 Structured Beamforming Methodp. 297
5.7.1 Decorrelation Analysisp. 297
5.7.2 Structured Gradient Algorithmp. 301
5.8 Correlated Broadband Sourcesp. 310
5.8.1 Structure of Array Correlation Matrixp. 310
5.8.2 Correlated Field Modelp. 312
5.8.3 Structured Beamforming Methodp. 313
5.8.4 Decorrelation Analysisp. 314
Notation and Abbreviationsp. 321
Referencesp. 323
6 Direction-of-Arrival Estimation Methodsp. 325
6.1 Spectral Estimation Methodsp. 326
6.1.1 Bartlett Methodp. 326
6.2 Minimum Variance Distortionless Response Estimatorp. 326
6.3 Linear Prediction Methodp. 327
6.4 Maximum Entropy Methodp. 327
6.5 Maximum Likelihood Methodp. 329
6.6 Eigenstructure Methodsp. 329
6.7 MUSIC Algorithmp. 330
6.7.1 Spectral MUSICp. 331
6.7.2 Root-MUSICp. 331
6.7.3 Constrained MUSICp. 331
6.7.4 Beam Space MUSICp. 332
6.8 Minimum Norm Methodp. 332
6.9 CLOSEST Methodp. 333
6.10 ESPRIT Methodp. 336
6.11 Weighted Subspace Fitting Methodp. 336
6.12 Review of Other Methodsp. 338
6.13 Preprocessing Techniquesp. 340
6.14 Estimating Source Numberp. 341
6.15 Performance Comparisonp. 343
6.16 Sensitivity Analysisp. 347
Notation and Abbreviationsp. 347
Referencesp. 348
7 Single-Antenna System in Fading Channelsp. 359
7.1 Fading Channelsp. 359
7.1.1 Large-Scale Fadingp. 361
7.1.2 Small-Scale Fadingp. 363
7.1.3 Distribution of Signal Powerp. 366
7.2 Channel Gainp. 367
7.3 Single-Antenna Systemp. 368
7.3.1 Noise-Limited Systemp. 368
7.3.2 Interference-Limited Systemp. 370
7.3.3 Interference with Nakagami Fading and Shadowingp. 373
7.3.4 Error Rate Performancep. 376
Notation and Abbreviationsp. 377
Referencesp. 379
8 Diversity Combiningp. 381
8.1 Selection Combinerp. 385
8.1.1 Noise-Limited Systemsp. 386
8.1.2 Interference-Limited Systemsp. 391
8.2 Switched Diversity Combinerp. 395
8.2.1 Outage Probabilityp. 395
8.2.2 Average Bit Error Ratep. 396
8.2.3 Correlated Fadingp. 398
8.3 Equal Gain Combinerp. 400
8.3.1 Noise-Limited Systemsp. 400
8.3.2 Interference-Limited Systemsp. 406
8.4 Maximum Ratio Combinerp. 408
8.4.1 Noise-Limited Systemsp. 409
8.4.2 Interference-Limited Systemsp. 415
8.5 Optimal Combinerp. 418
8.5.1 Mean Signal Power to Interference Power Ratiop. 419
8.5.2 Outage Probabilityp. 420
8.5.3 Average Bit Error Ratep. 420
8.6 Generalized Selection Combinerp. 421
8.6.1 Moment-Generating Functionsp. 422
8.6.2 Mean Output Signal-to-Noise Ratiop. 423
8.6.3 Outage Probabilityp. 425
8.6.4 Average Bit Error Ratep. 426
8.7 Cascade Diversity Combinerp. 428
8.7.1 Rayleigh Fading Environmentp. 429
8.7.2 Nakagami Fading Environmentp. 433
8.8 Macroscopic Diversity Combinerp. 435
8.8.1 Effect of Shadowingp. 435
8.8.2 Microscopic Plus Macroscopic Diversityp. 437
Notation and Abbreviationsp. 439
Referencesp. 441
Indexp. 445