Practical Digital Wireless Signals

Half-title......Page 3
Series-title......Page 4
Title......Page 5
Copyright......Page 6
Dedication......Page 7
Contents......Page 9
Preface......Page 19
Definitions and acronyms......Page 22
Terminology and notation......Page 27
1 Keying, states, and block diagram construction......Page 29
1.1 Radio communications: what really happens?......Page 30
1.2 Modulation states: “keyed”......Page 31
1.3.2 Polar representation......Page 34
1.3.3 Quadrature representation......Page 35
1.3.4 Transformations between signal representations......Page 37
1.4 Frequency domain representations......Page 39
1.5.1 Symbol construction......Page 41
1.5.2 Symbol-to-signal-state mapping......Page 42
1.5.3 State transitions......Page 43
1.5.5 Power amplifier (PA)......Page 45
Simplex......Page 46
Duplex......Page 47
Duplexer vs. diplexer......Page 48
For further reading......Page 50
2.1 Power spectral density (PSD)......Page 51
2.2 Occupied bandwidth......Page 56
Bounded power-spectral-density (B-PSD) bandwidth......Page 57
Fractional power-containment bandwidth......Page 59
Null-to-null bandwidth......Page 61
Equivalent white-noise signal bandwidth (ENSB)......Page 62
2.3 Bandlimiting filtering......Page 63
2.3.2 Filtering pulses......Page 65
2.3.3 Superposition......Page 66
2.3.5 Nyquist filters......Page 68
2.3.6 Matched filtering......Page 71
2.4.1 Constellation diagram......Page 75
2.4.3 “Eye” diagram......Page 76
2.5 Interference and near-far interference (NFI)......Page 78
2.6 Signals and noise......Page 80
2.6.3 Information bit-energy-to-noise density (IBEND) Eb/N0......Page 81
2.7 Channel (Shannon) capacity......Page 84
Bandwidth efficiency......Page 86
Energy (DC) efficiency......Page 87
Backoff efficiency......Page 89
Supply-referenced efficiency......Page 90
Power efficiency......Page 91
2.8.2 Error vector......Page 93
2.8.3 Off-channel power ratio......Page 94
Peak-to-average power ratio (PAPR)......Page 95
PDF/CDF/CCDF curves......Page 96
2.9 Circuitry impacts from the signal selection......Page 98
Envelope-varying (EV) signals......Page 99
For further reading......Page 100
3.1 DWC channel capacity – the fundamental work of Claude Shannon......Page 102
3.1.1 Basic capacity relationships to SNR......Page 103
3.1.2 Basic capacity relationships with respect to IBEND......Page 106
3.1.4 Power vs. bandwidth for a set capacity......Page 109
3.1.5 Signal design region: adaptive modulation......Page 111
3.2 Equivalent noise bandwidth (ENB)......Page 113
3.2.1 ENB of filters......Page 114
3.2.2 Limitations of the ENB concept......Page 115
Infinite-impulse-response (IIR) filters......Page 116
3.3.2 Generalized Nyquist filter construction (GNFC)......Page 117
3.3.3 The DZ (derivative-zeroed) pulse family......Page 123
3.3.4 Superposition lowpass filtering (SLPF)......Page 126
For further reading......Page 128
4.1.1 Amplitude shift keying definition......Page 130
4.1.2 Modulation index and envelope dynamic range......Page 131
4.1.4 Spectrum and signal bandwidth......Page 132
4.1.5 ASK bandwidth efficiency......Page 134
4.1.6 ASK power efficiency......Page 135
4.1.7 PAPR characteristics......Page 136
4.1.8 Additive noise......Page 137
4.2.1 Variable gain amplifier (VGA)......Page 139
4.2.2 PA DC-power modulation......Page 140
4.2.3 Complete-power keying for OOK......Page 141
4.3 ASK signal demodulation principles......Page 142
4.3.1 Diode......Page 146
4.3.2 Demodulating logamp/received-signal-strength indication (RSSI)......Page 147
4.3.3 Automatic gain control (AGC)......Page 148
4.3.4 Coherent......Page 149
For further reading......Page 151
5.1.1 Frequency shift keying definition......Page 152
5.1.2 Modulation index......Page 155
Important special case: minimum shift keying (MSK)......Page 158
5.1.3 Spectrum and signal bandwidth......Page 159
Important special cases: Gaussian-filtered FSK......Page 164
5.1.4 FSK bandwidth efficiency......Page 166
5.1.6 Doppler shift......Page 168
Threshold effect......Page 170
Clicks and doublets......Page 171
5.2.1 Switched oscillators......Page 173
5.2.2 Voltage-controlled oscillator (VCO)......Page 174
5.2.3 Fractional-division loop......Page 175
5.2.4 Two-point modulation......Page 176
5.2.5 Opened-loop modulation......Page 177
5.2.6 Direct digital (frequency) synthesis (DDS, or also DDFS)......Page 178
5.3 FSK signal demodulation principles......Page 179
5.3.1 Limiters: compression and capture effects......Page 180
5.3.3 Frequency discriminators......Page 183
Delay line......Page 184
5.3.4 D-flipflop (DFF)......Page 185
References......Page 186
For further reading......Page 187
6.1.1 Phase shift keying......Page 188
6.1.2 Vector diagrams......Page 191
CDF examples for linear transitions......Page 193
6.1.3 PSK phase diagram......Page 194
6.1.5 Offset modulation (O-PSK)......Page 195
6.1.6 Rotated modulation......Page 197
6.1.7 Spectrum and signal bandwidth......Page 198
6.1.8 Bandwidth efficiency......Page 202
6.1.10 Doppler effects......Page 203
6.1.11 Additive noise......Page 205
6.2 PSK signal generation......Page 206
6.2.2 Mixer (BPSK)......Page 207
6.3 PSK signal demodulation principles......Page 208
6.3.1 Quadrature demodulation......Page 209
6.3.2 Differential demodulation......Page 210
6.3.3 Direct phase demodulation......Page 211
For further reading......Page 212
7.2 Quadrature amplitude modulation (QAM)......Page 213
7.2.1 Constellation diagrams......Page 214
7.2.2 Spectrum and signal bandwidth......Page 217
7.2.4 Power efficiency......Page 218
7.2.5 PAPR characteristics......Page 220
7.2.7 Doppler sensitivity......Page 221
7.2.8 Additive noise performance......Page 223
7.2.9 Demodulation principles for QAM......Page 230
7.2.10 Tradeoff summary......Page 231
Why does OFDM exist?......Page 232
Basic OFDM principles......Page 234
7.3.1 OFDM fundamentals......Page 236
7.3.2 Waveform discontinuity......Page 238
7.3.3 Cyclic prefix......Page 239
7.3.4 OFDM constellation diagrams......Page 240
7.3.5 Spectrum and signal bandwidth......Page 241
7.3.6 Bandwidth efficiency......Page 242
7.3.7 PAPR characteristics......Page 244
7.3.8 Energy efficiency......Page 246
7.3.9 Doppler sensitivity......Page 247
7.3.10 Signal generation and demodulation......Page 248
Important special case: 3G long-term evolution (LTE)......Page 249
7.3.11 Demodulation principles for OFDM......Page 251
7.3.12 Tradeoff summary......Page 252
For further reading......Page 253
8.1 General principles and characteristics......Page 254
8.1.2 Synchronization......Page 256
8.1.3 Interference suppression......Page 259
8.1.4 Process gain......Page 260
8.1.5 Jamming margin......Page 261
8.1.6 Spreading codes, and chips......Page 262
8.2.1 Basic operation......Page 263
8.2.2 Synchronization......Page 265
8.2.4 Modulation selection......Page 266
8.2.6 Interference suppression......Page 267
8.3.1 Basic operation......Page 268
Negative input SNR......Page 269
8.3.2 Synchronization......Page 270
8.3.3 De-spreader location......Page 271
8.3.5 Process gain......Page 272
8.3.7 Jamming margin......Page 273
References......Page 274
For further reading......Page 275
9 Wireless propagation and antenna fundamentals......Page 276
9.1 Free-space propagation......Page 277
9.2 Antenna properties......Page 278
9.2.1 Antenna gain......Page 279
9.2.2 Directivity......Page 281
9.2.3 Near and far fields......Page 282
9.2.4 Polarization......Page 283
9.3 Path loss......Page 284
9.4 Optical equivalence of propagation......Page 286
9.4.1 Reflections......Page 287
9.4.2 Shadowing, diffraction, and refraction......Page 289
9.6 Fading......Page 290
Block errors and fade margin......Page 291
9.7 Diversity......Page 292
Polarization diversity......Page 293
9.8 Level diagrams......Page 294
GEO satellite system example......Page 295
Personal-area communication example......Page 296
For further reading......Page 297
10.1 Why do coding? And what is coding anyway?......Page 298
10.2 Basic principles of coding......Page 299
10.3 Coding for bandwidth efficiency......Page 301
10.4 Coding for spectrum control and link operation......Page 302
10.5.1 Approaching the Shannon Limit......Page 305
10.5.2 New tradeoffs......Page 308
Block coding for error detection......Page 309
Block coding for error correction......Page 310
10.5.4 Convolutional coding......Page 312
10.5.5 Interleaving: coding for burst errors......Page 315
10.5.6 Iteratively decoded coding (e.g. Turbo, LDPC)......Page 317
10.5.7 Combination coding: inner and outer codes......Page 318
Trellis diagrams......Page 320
10.6 Coding for channel throughput......Page 323
10.7 Equalization......Page 324
For further reading......Page 325
11.1 Carrier sense (CSMA)......Page 327
11.1.2 Hidden node problem......Page 328
11.2 Frequency division (FDMA)......Page 329
11.2.1 Channel designations......Page 330
11.2.2 Coverage strategies......Page 331
Duplexing......Page 332
11.3.1 Framing......Page 333
11.3.2 Burst ramp-up and ramp-down spectral effects......Page 335
11.4.1 Signal separation......Page 336
11.4.2 Multiple access interference (MAI)......Page 338
11.4.3 Power control is essential......Page 339
11.5 Orthogonal FDMA......Page 342
11.5.2 Orthogonality in the uplink......Page 343
11.6 Space division (SDMA)......Page 344
References......Page 346
For further reading......Page 347
12 Signal tradeoffs and system evolution......Page 348
12.1 Receiver implications of modulation choice......Page 350
12.2 Signal-bandwidth efficiency comparison......Page 355
12.3 Power amplifier cost issues......Page 358
12.4 Signal tolerance of channel-induced problems......Page 359
12.5 Keep-it-Simple ranking of DWC signals......Page 360
12.6 Existing systems and their modulation selections......Page 363
Long, long ago in a place not very far away…......Page 364
For further reading......Page 368
Appendix A: Phasor review......Page 369
Appendix B: Decibels (dB) really are simple......Page 371
Relative decibel measures......Page 373
C.1 Amplitude modulation (AM)......Page 375
C.2 Frequency modulation (FM)......Page 379
C.3 Phase modulation (PM)......Page 382
Narrowband PM (small phase excursions)......Page 384
Asymmetrical sideband magnitudes......Page 385
References......Page 386
D.1 Ideal quadrature modulation and demodulation......Page 387
D.2 First-order sources of error......Page 389
D.3 Error term analysis......Page 393
D.4 Conclusion......Page 399
Appendix E: Polar modulation and demodulation principles......Page 400
E.1 Polar modulation......Page 402
E.3 Threshold effect problem......Page 405
References......Page 406
F.1 Maximum-flatness derivation......Page 407
F.3 DZ pulse family-member examples......Page 411
F.4 Derivative-zeroed-even family......Page 412
Acknowledgments......Page 415
References......Page 416
Appendix G: Selected DWC standards and their modulations......Page 417
Index......Page 429