dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1 | /* |
kurtis.heimerl | a198d45 | 2011-11-26 03:19:28 +0000 | [diff] [blame] | 2 | * Copyright 2008, 2011 Free Software Foundation, Inc. |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 3 | * |
| 4 | * This software is distributed under the terms of the GNU Affero Public License. |
| 5 | * See the COPYING file in the main directory for details. |
| 6 | * |
| 7 | * This use of this software may be subject to additional restrictions. |
| 8 | * See the LEGAL file in the main directory for details. |
| 9 | |
| 10 | This program is free software: you can redistribute it and/or modify |
| 11 | it under the terms of the GNU Affero General Public License as published by |
| 12 | the Free Software Foundation, either version 3 of the License, or |
| 13 | (at your option) any later version. |
| 14 | |
| 15 | This program is distributed in the hope that it will be useful, |
| 16 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | GNU Affero General Public License for more details. |
| 19 | |
| 20 | You should have received a copy of the GNU Affero General Public License |
| 21 | along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 22 | |
| 23 | */ |
| 24 | |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 25 | #include "sigProcLib.h" |
| 26 | #include "GSMCommon.h" |
kurtis.heimerl | a198d45 | 2011-11-26 03:19:28 +0000 | [diff] [blame] | 27 | #include "sendLPF_961.h" |
| 28 | #include "rcvLPF_651.h" |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 29 | |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 30 | extern "C" { |
| 31 | #include "convolve.h" |
| 32 | } |
| 33 | |
Alexander Chemeris | d734e2d | 2013-06-16 14:30:58 +0400 | [diff] [blame] | 34 | using namespace GSM; |
| 35 | |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 36 | #define TABLESIZE 1024 |
| 37 | |
| 38 | /** Lookup tables for trigonometric approximation */ |
| 39 | float cosTable[TABLESIZE+1]; // add 1 element for wrap around |
| 40 | float sinTable[TABLESIZE+1]; |
| 41 | |
| 42 | /** Constants */ |
| 43 | static const float M_PI_F = (float)M_PI; |
| 44 | static const float M_2PI_F = (float)(2.0*M_PI); |
| 45 | static const float M_1_2PI_F = 1/M_2PI_F; |
| 46 | |
| 47 | /** Static vectors that contain a precomputed +/- f_b/4 sinusoid */ |
| 48 | signalVector *GMSKRotation = NULL; |
| 49 | signalVector *GMSKReverseRotation = NULL; |
| 50 | |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 51 | /* |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 52 | * RACH and midamble correlation waveforms. Store the buffer separately |
| 53 | * because we need to allocate it explicitly outside of the signal vector |
| 54 | * constructor. This is because C++ (prior to C++11) is unable to natively |
| 55 | * perform 16-byte memory alignment required by many SSE instructions. |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 56 | */ |
| 57 | struct CorrelationSequence { |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 58 | CorrelationSequence() : sequence(NULL), buffer(NULL) |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 59 | { |
| 60 | } |
| 61 | |
| 62 | ~CorrelationSequence() |
| 63 | { |
| 64 | delete sequence; |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 65 | free(buffer); |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 66 | } |
| 67 | |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 68 | signalVector *sequence; |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 69 | void *buffer; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 70 | float TOA; |
| 71 | complex gain; |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 72 | }; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 73 | |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 74 | /* |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 75 | * Gaussian and empty modulation pulses. Like the correlation sequences, |
| 76 | * store the runtime (Gaussian) buffer separately because of needed alignment |
| 77 | * for SSE instructions. |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 78 | */ |
| 79 | struct PulseSequence { |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 80 | PulseSequence() : c0(NULL), c1(NULL), empty(NULL), |
| 81 | c0_buffer(NULL), c1_buffer(NULL) |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 82 | { |
| 83 | } |
| 84 | |
| 85 | ~PulseSequence() |
| 86 | { |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 87 | delete c0; |
| 88 | delete c1; |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 89 | delete empty; |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 90 | free(c0_buffer); |
| 91 | free(c1_buffer); |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 92 | } |
| 93 | |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 94 | signalVector *c0; |
| 95 | signalVector *c1; |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 96 | signalVector *empty; |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 97 | void *c0_buffer; |
| 98 | void *c1_buffer; |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 99 | }; |
| 100 | |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 101 | CorrelationSequence *gMidambles[] = {NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL}; |
| 102 | CorrelationSequence *gRACHSequence = NULL; |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 103 | PulseSequence *GSMPulse = NULL; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 104 | |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 105 | void sigProcLibDestroy() |
| 106 | { |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 107 | for (int i = 0; i < 8; i++) { |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 108 | delete gMidambles[i]; |
| 109 | gMidambles[i] = NULL; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 110 | } |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 111 | |
| 112 | delete GMSKRotation; |
| 113 | delete GMSKReverseRotation; |
| 114 | delete gRACHSequence; |
| 115 | delete GSMPulse; |
| 116 | |
| 117 | GMSKRotation = NULL; |
| 118 | GMSKReverseRotation = NULL; |
| 119 | gRACHSequence = NULL; |
| 120 | GSMPulse = NULL; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 121 | } |
| 122 | |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 123 | // dB relative to 1.0. |
| 124 | // if > 1.0, then return 0 dB |
| 125 | float dB(float x) { |
| 126 | |
| 127 | float arg = 1.0F; |
| 128 | float dB = 0.0F; |
| 129 | |
| 130 | if (x >= 1.0F) return 0.0F; |
| 131 | if (x <= 0.0F) return -200.0F; |
| 132 | |
| 133 | float prevArg = arg; |
| 134 | float prevdB = dB; |
| 135 | float stepSize = 16.0F; |
| 136 | float dBstepSize = 12.0F; |
| 137 | while (stepSize > 1.0F) { |
| 138 | do { |
| 139 | prevArg = arg; |
| 140 | prevdB = dB; |
| 141 | arg /= stepSize; |
| 142 | dB -= dBstepSize; |
| 143 | } while (arg > x); |
| 144 | arg = prevArg; |
| 145 | dB = prevdB; |
| 146 | stepSize *= 0.5F; |
| 147 | dBstepSize -= 3.0F; |
| 148 | } |
| 149 | return ((arg-x)*(dB-3.0F) + (x-arg*0.5F)*dB)/(arg - arg*0.5F); |
| 150 | |
| 151 | } |
| 152 | |
| 153 | // 10^(-dB/10), inverse of dB func. |
| 154 | float dBinv(float x) { |
| 155 | |
| 156 | float arg = 1.0F; |
| 157 | float dB = 0.0F; |
| 158 | |
| 159 | if (x >= 0.0F) return 1.0F; |
| 160 | if (x <= -200.0F) return 0.0F; |
| 161 | |
| 162 | float prevArg = arg; |
| 163 | float prevdB = dB; |
| 164 | float stepSize = 16.0F; |
| 165 | float dBstepSize = 12.0F; |
| 166 | while (stepSize > 1.0F) { |
| 167 | do { |
| 168 | prevArg = arg; |
| 169 | prevdB = dB; |
| 170 | arg /= stepSize; |
| 171 | dB -= dBstepSize; |
| 172 | } while (dB > x); |
| 173 | arg = prevArg; |
| 174 | dB = prevdB; |
| 175 | stepSize *= 0.5F; |
| 176 | dBstepSize -= 3.0F; |
| 177 | } |
| 178 | |
| 179 | return ((dB-x)*(arg*0.5F)+(x-(dB-3.0F))*(arg))/3.0F; |
| 180 | |
| 181 | } |
| 182 | |
| 183 | float vectorNorm2(const signalVector &x) |
| 184 | { |
| 185 | signalVector::const_iterator xPtr = x.begin(); |
| 186 | float Energy = 0.0; |
| 187 | for (;xPtr != x.end();xPtr++) { |
| 188 | Energy += xPtr->norm2(); |
| 189 | } |
| 190 | return Energy; |
| 191 | } |
| 192 | |
| 193 | |
| 194 | float vectorPower(const signalVector &x) |
| 195 | { |
| 196 | return vectorNorm2(x)/x.size(); |
| 197 | } |
| 198 | |
| 199 | /** compute cosine via lookup table */ |
| 200 | float cosLookup(const float x) |
| 201 | { |
| 202 | float arg = x*M_1_2PI_F; |
| 203 | while (arg > 1.0F) arg -= 1.0F; |
| 204 | while (arg < 0.0F) arg += 1.0F; |
| 205 | |
| 206 | const float argT = arg*((float)TABLESIZE); |
| 207 | const int argI = (int)argT; |
| 208 | const float delta = argT-argI; |
| 209 | const float iDelta = 1.0F-delta; |
| 210 | return iDelta*cosTable[argI] + delta*cosTable[argI+1]; |
| 211 | } |
| 212 | |
| 213 | /** compute sine via lookup table */ |
| 214 | float sinLookup(const float x) |
| 215 | { |
| 216 | float arg = x*M_1_2PI_F; |
| 217 | while (arg > 1.0F) arg -= 1.0F; |
| 218 | while (arg < 0.0F) arg += 1.0F; |
| 219 | |
| 220 | const float argT = arg*((float)TABLESIZE); |
| 221 | const int argI = (int)argT; |
| 222 | const float delta = argT-argI; |
| 223 | const float iDelta = 1.0F-delta; |
| 224 | return iDelta*sinTable[argI] + delta*sinTable[argI+1]; |
| 225 | } |
| 226 | |
| 227 | |
| 228 | /** compute e^(-jx) via lookup table. */ |
| 229 | complex expjLookup(float x) |
| 230 | { |
| 231 | float arg = x*M_1_2PI_F; |
| 232 | while (arg > 1.0F) arg -= 1.0F; |
| 233 | while (arg < 0.0F) arg += 1.0F; |
| 234 | |
| 235 | const float argT = arg*((float)TABLESIZE); |
| 236 | const int argI = (int)argT; |
| 237 | const float delta = argT-argI; |
| 238 | const float iDelta = 1.0F-delta; |
| 239 | return complex(iDelta*cosTable[argI] + delta*cosTable[argI+1], |
| 240 | iDelta*sinTable[argI] + delta*sinTable[argI+1]); |
| 241 | } |
| 242 | |
| 243 | /** Library setup functions */ |
| 244 | void initTrigTables() { |
| 245 | for (int i = 0; i < TABLESIZE+1; i++) { |
| 246 | cosTable[i] = cos(2.0*M_PI*i/TABLESIZE); |
| 247 | sinTable[i] = sin(2.0*M_PI*i/TABLESIZE); |
| 248 | } |
| 249 | } |
| 250 | |
Thomas Tsou | e01e1b3 | 2013-09-02 13:24:13 +0800 | [diff] [blame] | 251 | void initGMSKRotationTables(int sps) |
| 252 | { |
| 253 | GMSKRotation = new signalVector(157 * sps); |
| 254 | GMSKReverseRotation = new signalVector(157 * sps); |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 255 | signalVector::iterator rotPtr = GMSKRotation->begin(); |
| 256 | signalVector::iterator revPtr = GMSKReverseRotation->begin(); |
| 257 | float phase = 0.0; |
| 258 | while (rotPtr != GMSKRotation->end()) { |
| 259 | *rotPtr++ = expjLookup(phase); |
| 260 | *revPtr++ = expjLookup(-phase); |
Thomas Tsou | e01e1b3 | 2013-09-02 13:24:13 +0800 | [diff] [blame] | 261 | phase += M_PI_F / 2.0F / (float) sps; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 262 | } |
| 263 | } |
| 264 | |
Thomas Tsou | 9520ecd | 2013-08-20 18:55:33 -0400 | [diff] [blame] | 265 | bool sigProcLibSetup(int sps) |
Thomas Tsou | e01e1b3 | 2013-09-02 13:24:13 +0800 | [diff] [blame] | 266 | { |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 267 | if (sps != 4) |
Thomas Tsou | 9520ecd | 2013-08-20 18:55:33 -0400 | [diff] [blame] | 268 | return false; |
| 269 | |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 270 | initTrigTables(); |
Thomas Tsou | e01e1b3 | 2013-09-02 13:24:13 +0800 | [diff] [blame] | 271 | initGMSKRotationTables(sps); |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 272 | generateGSMPulse(sps, 2); |
Thomas Tsou | 9520ecd | 2013-08-20 18:55:33 -0400 | [diff] [blame] | 273 | |
| 274 | if (!generateRACHSequence(sps)) { |
| 275 | sigProcLibDestroy(); |
| 276 | return false; |
| 277 | } |
| 278 | |
| 279 | return true; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 280 | } |
| 281 | |
| 282 | void GMSKRotate(signalVector &x) { |
| 283 | signalVector::iterator xPtr = x.begin(); |
| 284 | signalVector::iterator rotPtr = GMSKRotation->begin(); |
| 285 | if (x.isRealOnly()) { |
| 286 | while (xPtr < x.end()) { |
| 287 | *xPtr = *rotPtr++ * (xPtr->real()); |
| 288 | xPtr++; |
| 289 | } |
| 290 | } |
| 291 | else { |
| 292 | while (xPtr < x.end()) { |
| 293 | *xPtr = *rotPtr++ * (*xPtr); |
| 294 | xPtr++; |
| 295 | } |
| 296 | } |
| 297 | } |
| 298 | |
| 299 | void GMSKReverseRotate(signalVector &x) { |
| 300 | signalVector::iterator xPtr= x.begin(); |
| 301 | signalVector::iterator rotPtr = GMSKReverseRotation->begin(); |
| 302 | if (x.isRealOnly()) { |
| 303 | while (xPtr < x.end()) { |
| 304 | *xPtr = *rotPtr++ * (xPtr->real()); |
| 305 | xPtr++; |
| 306 | } |
| 307 | } |
| 308 | else { |
| 309 | while (xPtr < x.end()) { |
| 310 | *xPtr = *rotPtr++ * (*xPtr); |
| 311 | xPtr++; |
| 312 | } |
| 313 | } |
| 314 | } |
| 315 | |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 316 | signalVector *convolve(const signalVector *x, |
| 317 | const signalVector *h, |
| 318 | signalVector *y, |
| 319 | ConvType spanType, int start, |
| 320 | unsigned len, unsigned step, int offset) |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 321 | { |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 322 | int rc, head = 0, tail = 0; |
| 323 | bool alloc = false, append = false; |
| 324 | const signalVector *_x = NULL; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 325 | |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 326 | if (!x || !h) |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 327 | return NULL; |
| 328 | |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 329 | switch (spanType) { |
| 330 | case START_ONLY: |
| 331 | start = 0; |
| 332 | head = h->size(); |
| 333 | len = x->size(); |
| 334 | append = true; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 335 | break; |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 336 | case NO_DELAY: |
| 337 | start = h->size() / 2; |
| 338 | head = start; |
| 339 | tail = start; |
| 340 | len = x->size(); |
| 341 | append = true; |
| 342 | break; |
| 343 | case CUSTOM: |
| 344 | if (start < h->size() - 1) { |
| 345 | head = h->size() - start; |
| 346 | append = true; |
| 347 | } |
| 348 | if (start + len > x->size()) { |
| 349 | tail = start + len - x->size(); |
| 350 | append = true; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 351 | } |
| 352 | break; |
| 353 | default: |
| 354 | return NULL; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 355 | } |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 356 | |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 357 | /* |
| 358 | * Error if the output vector is too small. Create the output vector |
| 359 | * if the pointer is NULL. |
| 360 | */ |
| 361 | if (y && (len > y->size())) |
| 362 | return NULL; |
| 363 | if (!y) { |
| 364 | y = new signalVector(len); |
| 365 | alloc = true; |
| 366 | } |
| 367 | |
| 368 | /* Prepend or post-pend the input vector if the parameters require it */ |
| 369 | if (append) |
| 370 | _x = new signalVector(*x, head, tail); |
| 371 | else |
| 372 | _x = x; |
| 373 | |
| 374 | /* |
| 375 | * Four convovle types: |
| 376 | * 1. Complex-Real (aligned) |
| 377 | * 2. Complex-Complex (aligned) |
| 378 | * 3. Complex-Real (!aligned) |
| 379 | * 4. Complex-Complex (!aligned) |
| 380 | */ |
| 381 | if (h->isRealOnly() && h->isAligned()) { |
| 382 | rc = convolve_real((float *) _x->begin(), _x->size(), |
| 383 | (float *) h->begin(), h->size(), |
| 384 | (float *) y->begin(), y->size(), |
| 385 | start, len, step, offset); |
| 386 | } else if (!h->isRealOnly() && h->isAligned()) { |
| 387 | rc = convolve_complex((float *) _x->begin(), _x->size(), |
| 388 | (float *) h->begin(), h->size(), |
| 389 | (float *) y->begin(), y->size(), |
| 390 | start, len, step, offset); |
| 391 | } else if (h->isRealOnly() && !h->isAligned()) { |
| 392 | rc = base_convolve_real((float *) _x->begin(), _x->size(), |
| 393 | (float *) h->begin(), h->size(), |
| 394 | (float *) y->begin(), y->size(), |
| 395 | start, len, step, offset); |
| 396 | } else if (!h->isRealOnly() && !h->isAligned()) { |
| 397 | rc = base_convolve_complex((float *) _x->begin(), _x->size(), |
| 398 | (float *) h->begin(), h->size(), |
| 399 | (float *) y->begin(), y->size(), |
| 400 | start, len, step, offset); |
| 401 | } else { |
| 402 | rc = -1; |
| 403 | } |
| 404 | |
| 405 | if (append) |
| 406 | delete _x; |
| 407 | |
| 408 | if (rc < 0) { |
| 409 | if (alloc) |
| 410 | delete y; |
| 411 | return NULL; |
| 412 | } |
| 413 | |
| 414 | return y; |
| 415 | } |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 416 | |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 417 | bool generateC1Pulse(int sps) |
| 418 | { |
| 419 | int len; |
| 420 | |
| 421 | switch (sps) { |
| 422 | case 4: |
| 423 | len = 8; |
| 424 | break; |
| 425 | default: |
| 426 | return false; |
| 427 | } |
| 428 | |
| 429 | GSMPulse->c1_buffer = convolve_h_alloc(len); |
| 430 | GSMPulse->c1 = new signalVector((complex *) |
| 431 | GSMPulse->c1_buffer, 0, len); |
| 432 | GSMPulse->c1->isRealOnly(true); |
| 433 | |
| 434 | /* Enable alignment for SSE usage */ |
| 435 | GSMPulse->c1->setAligned(true); |
| 436 | |
| 437 | signalVector::iterator xP = GSMPulse->c1->begin(); |
| 438 | |
| 439 | switch (sps) { |
| 440 | case 4: |
| 441 | /* BT = 0.30 */ |
| 442 | *xP++ = 0.0; |
| 443 | *xP++ = 8.16373112e-03; |
| 444 | *xP++ = 2.84385729e-02; |
| 445 | *xP++ = 5.64158904e-02; |
| 446 | *xP++ = 7.05463553e-02; |
| 447 | *xP++ = 5.64158904e-02; |
| 448 | *xP++ = 2.84385729e-02; |
| 449 | *xP++ = 8.16373112e-03; |
| 450 | } |
| 451 | |
| 452 | return true; |
| 453 | } |
| 454 | |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 455 | void generateGSMPulse(int sps, int symbolLength) |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 456 | { |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 457 | int len; |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 458 | float arg, avg, center; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 459 | |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 460 | delete GSMPulse; |
| 461 | |
| 462 | /* Store a single tap filter used for correlation sequence generation */ |
| 463 | GSMPulse = new PulseSequence(); |
| 464 | GSMPulse->empty = new signalVector(1); |
| 465 | GSMPulse->empty->isRealOnly(true); |
| 466 | *(GSMPulse->empty->begin()) = 1.0f; |
| 467 | |
Thomas Tsou | 98e58b9 | 2013-08-21 13:59:52 -0400 | [diff] [blame] | 468 | /* |
| 469 | * For 4 samples-per-symbol use a precomputed single pulse Laurent |
| 470 | * approximation. This should yields below 2 degrees of phase error at |
| 471 | * the modulator output. Use the existing pulse approximation for all |
| 472 | * other oversampling factors. |
| 473 | */ |
| 474 | switch (sps) { |
| 475 | case 4: |
| 476 | len = 16; |
| 477 | break; |
| 478 | default: |
| 479 | len = sps * symbolLength; |
| 480 | if (len < 4) |
| 481 | len = 4; |
| 482 | } |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 483 | |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 484 | GSMPulse->c0_buffer = convolve_h_alloc(len); |
| 485 | GSMPulse->c0 = new signalVector((complex *) |
| 486 | GSMPulse->c0_buffer, 0, len); |
| 487 | GSMPulse->c0->isRealOnly(true); |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 488 | |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 489 | /* Enable alingnment for SSE usage */ |
| 490 | GSMPulse->c0->setAligned(true); |
| 491 | |
| 492 | signalVector::iterator xP = GSMPulse->c0->begin(); |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 493 | |
Thomas Tsou | 98e58b9 | 2013-08-21 13:59:52 -0400 | [diff] [blame] | 494 | if (sps == 4) { |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 495 | *xP++ = 0.0; |
Thomas Tsou | 98e58b9 | 2013-08-21 13:59:52 -0400 | [diff] [blame] | 496 | *xP++ = 4.46348606e-03; |
| 497 | *xP++ = 2.84385729e-02; |
| 498 | *xP++ = 1.03184855e-01; |
| 499 | *xP++ = 2.56065552e-01; |
| 500 | *xP++ = 4.76375085e-01; |
| 501 | *xP++ = 7.05961177e-01; |
| 502 | *xP++ = 8.71291644e-01; |
| 503 | *xP++ = 9.29453645e-01; |
| 504 | *xP++ = 8.71291644e-01; |
| 505 | *xP++ = 7.05961177e-01; |
| 506 | *xP++ = 4.76375085e-01; |
| 507 | *xP++ = 2.56065552e-01; |
| 508 | *xP++ = 1.03184855e-01; |
| 509 | *xP++ = 2.84385729e-02; |
| 510 | *xP++ = 4.46348606e-03; |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 511 | generateC1Pulse(sps); |
Thomas Tsou | 98e58b9 | 2013-08-21 13:59:52 -0400 | [diff] [blame] | 512 | } else { |
| 513 | center = (float) (len - 1.0) / 2.0; |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 514 | |
Thomas Tsou | 98e58b9 | 2013-08-21 13:59:52 -0400 | [diff] [blame] | 515 | /* GSM pulse approximation */ |
| 516 | for (int i = 0; i < len; i++) { |
| 517 | arg = ((float) i - center) / (float) sps; |
| 518 | *xP++ = 0.96 * exp(-1.1380 * arg * arg - |
| 519 | 0.527 * arg * arg * arg * arg); |
| 520 | } |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 521 | |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 522 | avg = sqrtf(vectorNorm2(*GSMPulse->c0) / sps); |
| 523 | xP = GSMPulse->c0->begin(); |
| 524 | for (int i = 0; i < len; i++) |
| 525 | *xP++ /= avg; |
| 526 | } |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 527 | } |
| 528 | |
| 529 | signalVector* frequencyShift(signalVector *y, |
| 530 | signalVector *x, |
| 531 | float freq, |
| 532 | float startPhase, |
| 533 | float *finalPhase) |
| 534 | { |
| 535 | |
| 536 | if (!x) return NULL; |
| 537 | |
| 538 | if (y==NULL) { |
| 539 | y = new signalVector(x->size()); |
| 540 | y->isRealOnly(x->isRealOnly()); |
| 541 | if (y==NULL) return NULL; |
| 542 | } |
| 543 | |
| 544 | if (y->size() < x->size()) return NULL; |
| 545 | |
| 546 | float phase = startPhase; |
| 547 | signalVector::iterator yP = y->begin(); |
| 548 | signalVector::iterator xPEnd = x->end(); |
| 549 | signalVector::iterator xP = x->begin(); |
| 550 | |
| 551 | if (x->isRealOnly()) { |
| 552 | while (xP < xPEnd) { |
| 553 | (*yP++) = expjLookup(phase)*( (xP++)->real() ); |
| 554 | phase += freq; |
| 555 | } |
| 556 | } |
| 557 | else { |
| 558 | while (xP < xPEnd) { |
| 559 | (*yP++) = (*xP++)*expjLookup(phase); |
| 560 | phase += freq; |
| 561 | } |
| 562 | } |
| 563 | |
| 564 | |
| 565 | if (finalPhase) *finalPhase = phase; |
| 566 | |
| 567 | return y; |
| 568 | } |
| 569 | |
| 570 | signalVector* reverseConjugate(signalVector *b) |
| 571 | { |
| 572 | signalVector *tmp = new signalVector(b->size()); |
| 573 | tmp->isRealOnly(b->isRealOnly()); |
| 574 | signalVector::iterator bP = b->begin(); |
| 575 | signalVector::iterator bPEnd = b->end(); |
| 576 | signalVector::iterator tmpP = tmp->end()-1; |
| 577 | if (!b->isRealOnly()) { |
| 578 | while (bP < bPEnd) { |
| 579 | *tmpP-- = bP->conj(); |
| 580 | bP++; |
| 581 | } |
| 582 | } |
| 583 | else { |
| 584 | while (bP < bPEnd) { |
| 585 | *tmpP-- = bP->real(); |
| 586 | bP++; |
| 587 | } |
| 588 | } |
| 589 | |
| 590 | return tmp; |
| 591 | } |
| 592 | |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 593 | /* soft output slicer */ |
| 594 | bool vectorSlicer(signalVector *x) |
| 595 | { |
| 596 | |
| 597 | signalVector::iterator xP = x->begin(); |
| 598 | signalVector::iterator xPEnd = x->end(); |
| 599 | while (xP < xPEnd) { |
| 600 | *xP = (complex) (0.5*(xP->real()+1.0F)); |
| 601 | if (xP->real() > 1.0) *xP = 1.0; |
| 602 | if (xP->real() < 0.0) *xP = 0.0; |
| 603 | xP++; |
| 604 | } |
| 605 | return true; |
| 606 | } |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 607 | |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 608 | static signalVector *rotateBurst(const BitVector &wBurst, |
| 609 | int guardPeriodLength, int sps) |
| 610 | { |
| 611 | int burst_len; |
| 612 | signalVector *pulse, rotated, *shaped; |
| 613 | signalVector::iterator itr; |
| 614 | |
| 615 | pulse = GSMPulse->empty; |
| 616 | burst_len = sps * (wBurst.size() + guardPeriodLength); |
| 617 | rotated = signalVector(burst_len); |
| 618 | itr = rotated.begin(); |
| 619 | |
| 620 | for (unsigned i = 0; i < wBurst.size(); i++) { |
| 621 | *itr = 2.0 * (wBurst[i] & 0x01) - 1.0; |
| 622 | itr += sps; |
| 623 | } |
| 624 | |
| 625 | GMSKRotate(rotated); |
| 626 | rotated.isRealOnly(false); |
| 627 | |
| 628 | /* Dummy filter operation */ |
| 629 | shaped = convolve(&rotated, pulse, NULL, START_ONLY); |
| 630 | if (!shaped) |
| 631 | return NULL; |
| 632 | |
| 633 | return shaped; |
| 634 | } |
| 635 | |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 636 | /* Assume input bits are not differentially encoded */ |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 637 | signalVector *modulateBurst(const BitVector &wBurst, int guardPeriodLength, |
| 638 | int sps, bool emptyPulse) |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 639 | { |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 640 | int burst_len; |
| 641 | float phase; |
| 642 | signalVector *c0_pulse, *c1_pulse, c0_burst, c1_burst, *c0_shaped, *c1_shaped; |
| 643 | signalVector::iterator c0_itr, c1_itr; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 644 | |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 645 | if (emptyPulse) |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 646 | return rotateBurst(wBurst, guardPeriodLength, sps); |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 647 | |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 648 | /* |
| 649 | * Apply before and after bits to reduce phase error at burst edges. |
| 650 | * Make sure there is enough room in the burst to accodmodate the bits. |
| 651 | */ |
| 652 | if (guardPeriodLength < 4) |
| 653 | guardPeriodLength = 4; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 654 | |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 655 | c0_pulse = GSMPulse->c0; |
| 656 | c1_pulse = GSMPulse->c1; |
| 657 | |
| 658 | burst_len = sps * (wBurst.size() + guardPeriodLength); |
| 659 | |
| 660 | c0_burst = signalVector(burst_len); |
| 661 | c0_burst.isRealOnly(true); |
| 662 | c0_itr = c0_burst.begin(); |
| 663 | |
| 664 | c1_burst = signalVector(burst_len); |
| 665 | c1_burst.isRealOnly(true); |
| 666 | c1_itr = c1_burst.begin(); |
| 667 | |
| 668 | /* Padded differential start bits */ |
| 669 | *c0_itr = 2.0 * (0x00 & 0x01) - 1.0; |
| 670 | c0_itr += sps; |
| 671 | |
| 672 | /* Main burst bits */ |
| 673 | for (unsigned i = 0; i < wBurst.size(); i++) { |
| 674 | *c0_itr = 2.0 * (wBurst[i] & 0x01) - 1.0; |
| 675 | c0_itr += sps; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 676 | } |
| 677 | |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 678 | /* Padded differential end bits */ |
| 679 | *c0_itr = 2.0 * (0x01 & 0x01) - 1.0; |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 680 | |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 681 | GMSKRotate(c0_burst); |
| 682 | c0_burst.isRealOnly(false); |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 683 | |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 684 | c0_itr = c0_burst.begin(); |
| 685 | c0_itr += sps * 2; |
| 686 | c1_itr += sps * 2; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 687 | |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 688 | /* Start magic */ |
| 689 | phase = 2.0 * ((0x01 & 0x01) ^ (0x01 & 0x01)) - 1.0; |
| 690 | *c1_itr = *c0_itr * Complex<float>(0, phase); |
| 691 | c0_itr += sps; |
| 692 | c1_itr += sps; |
| 693 | |
| 694 | /* Generate C1 phase coefficients */ |
| 695 | for (unsigned i = 2; i < wBurst.size(); i++) { |
| 696 | phase = 2.0 * ((wBurst[i - 1] & 0x01) ^ (wBurst[i - 2] & 0x01)) - 1.0; |
| 697 | *c1_itr = *c0_itr * Complex<float>(0, phase); |
| 698 | |
| 699 | c0_itr += sps; |
| 700 | c1_itr += sps; |
| 701 | } |
| 702 | |
| 703 | /* End magic */ |
| 704 | int i = wBurst.size(); |
| 705 | phase = 2.0 * ((wBurst[i-1] & 0x01) ^ (wBurst[i-2] & 0x01)) - 1.0; |
| 706 | *c1_itr = *c0_itr * Complex<float>(0, phase); |
| 707 | |
| 708 | /* Primary (C0) and secondary (C1) pulse shaping */ |
| 709 | c0_shaped = convolve(&c0_burst, c0_pulse, NULL, START_ONLY); |
| 710 | c1_shaped = convolve(&c1_burst, c1_pulse, NULL, START_ONLY); |
| 711 | |
| 712 | /* Sum pulse shaped outputs */ |
| 713 | c0_itr = c0_shaped->begin(); |
| 714 | c1_itr = c1_shaped->begin(); |
| 715 | for (unsigned i = 0; i < c0_shaped->size(); i++ ) |
| 716 | *c0_itr++ += *c1_itr++; |
| 717 | |
| 718 | delete c1_shaped; |
| 719 | |
| 720 | return c0_shaped; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 721 | } |
| 722 | |
| 723 | float sinc(float x) |
| 724 | { |
| 725 | if ((x >= 0.01F) || (x <= -0.01F)) return (sinLookup(x)/x); |
| 726 | return 1.0F; |
| 727 | } |
| 728 | |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 729 | bool delayVector(signalVector &wBurst, float delay) |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 730 | { |
| 731 | |
| 732 | int intOffset = (int) floor(delay); |
| 733 | float fracOffset = delay - intOffset; |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 734 | |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 735 | // do fractional shift first, only do it for reasonable offsets |
| 736 | if (fabs(fracOffset) > 1e-2) { |
| 737 | // create sinc function |
| 738 | signalVector sincVector(21); |
| 739 | sincVector.isRealOnly(true); |
Thomas Tsou | 0c260ae | 2013-08-22 18:40:43 -0400 | [diff] [blame] | 740 | signalVector::iterator sincBurstItr = sincVector.end(); |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 741 | for (int i = 0; i < 21; i++) |
Thomas Tsou | 0c260ae | 2013-08-22 18:40:43 -0400 | [diff] [blame] | 742 | *--sincBurstItr = (complex) sinc(M_PI_F*(i-10-fracOffset)); |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 743 | |
| 744 | signalVector shiftedBurst(wBurst.size()); |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 745 | if (!convolve(&wBurst, &sincVector, &shiftedBurst, NO_DELAY)) |
| 746 | return false; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 747 | wBurst.clone(shiftedBurst); |
| 748 | } |
| 749 | |
| 750 | if (intOffset < 0) { |
| 751 | intOffset = -intOffset; |
| 752 | signalVector::iterator wBurstItr = wBurst.begin(); |
| 753 | signalVector::iterator shiftedItr = wBurst.begin()+intOffset; |
| 754 | while (shiftedItr < wBurst.end()) |
| 755 | *wBurstItr++ = *shiftedItr++; |
| 756 | while (wBurstItr < wBurst.end()) |
| 757 | *wBurstItr++ = 0.0; |
| 758 | } |
| 759 | else { |
| 760 | signalVector::iterator wBurstItr = wBurst.end()-1; |
| 761 | signalVector::iterator shiftedItr = wBurst.end()-1-intOffset; |
| 762 | while (shiftedItr >= wBurst.begin()) |
| 763 | *wBurstItr-- = *shiftedItr--; |
| 764 | while (wBurstItr >= wBurst.begin()) |
| 765 | *wBurstItr-- = 0.0; |
| 766 | } |
| 767 | } |
| 768 | |
| 769 | signalVector *gaussianNoise(int length, |
| 770 | float variance, |
| 771 | complex mean) |
| 772 | { |
| 773 | |
| 774 | signalVector *noise = new signalVector(length); |
| 775 | signalVector::iterator nPtr = noise->begin(); |
| 776 | float stddev = sqrtf(variance); |
| 777 | while (nPtr < noise->end()) { |
| 778 | float u1 = (float) rand()/ (float) RAND_MAX; |
| 779 | while (u1==0.0) |
| 780 | u1 = (float) rand()/ (float) RAND_MAX; |
| 781 | float u2 = (float) rand()/ (float) RAND_MAX; |
| 782 | float arg = 2.0*M_PI*u2; |
| 783 | *nPtr = mean + stddev*complex(cos(arg),sin(arg))*sqrtf(-2.0*log(u1)); |
| 784 | nPtr++; |
| 785 | } |
| 786 | |
| 787 | return noise; |
| 788 | } |
| 789 | |
| 790 | complex interpolatePoint(const signalVector &inSig, |
| 791 | float ix) |
| 792 | { |
| 793 | |
| 794 | int start = (int) (floor(ix) - 10); |
| 795 | if (start < 0) start = 0; |
| 796 | int end = (int) (floor(ix) + 11); |
| 797 | if ((unsigned) end > inSig.size()-1) end = inSig.size()-1; |
| 798 | |
| 799 | complex pVal = 0.0; |
| 800 | if (!inSig.isRealOnly()) { |
| 801 | for (int i = start; i < end; i++) |
| 802 | pVal += inSig[i] * sinc(M_PI_F*(i-ix)); |
| 803 | } |
| 804 | else { |
| 805 | for (int i = start; i < end; i++) |
| 806 | pVal += inSig[i].real() * sinc(M_PI_F*(i-ix)); |
| 807 | } |
| 808 | |
| 809 | return pVal; |
| 810 | } |
| 811 | |
Thomas Tsou | fb6e757 | 2013-09-02 14:39:35 +0800 | [diff] [blame] | 812 | static complex fastPeakDetect(const signalVector &rxBurst, float *index) |
| 813 | { |
| 814 | float val, max = 0.0f; |
| 815 | complex amp; |
| 816 | int _index = -1; |
| 817 | |
| 818 | for (int i = 0; i < rxBurst.size(); i++) { |
| 819 | val = rxBurst[i].norm2(); |
| 820 | if (val > max) { |
| 821 | max = val; |
| 822 | _index = i; |
| 823 | amp = rxBurst[i]; |
| 824 | } |
| 825 | } |
| 826 | |
| 827 | if (index) |
| 828 | *index = (float) _index; |
| 829 | |
| 830 | return amp; |
| 831 | } |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 832 | |
| 833 | complex peakDetect(const signalVector &rxBurst, |
| 834 | float *peakIndex, |
| 835 | float *avgPwr) |
| 836 | { |
| 837 | |
| 838 | |
| 839 | complex maxVal = 0.0; |
| 840 | float maxIndex = -1; |
| 841 | float sumPower = 0.0; |
| 842 | |
| 843 | for (unsigned int i = 0; i < rxBurst.size(); i++) { |
| 844 | float samplePower = rxBurst[i].norm2(); |
| 845 | if (samplePower > maxVal.real()) { |
| 846 | maxVal = samplePower; |
| 847 | maxIndex = i; |
| 848 | } |
| 849 | sumPower += samplePower; |
| 850 | } |
| 851 | |
| 852 | // interpolate around the peak |
| 853 | // to save computation, we'll use early-late balancing |
| 854 | float earlyIndex = maxIndex-1; |
| 855 | float lateIndex = maxIndex+1; |
| 856 | |
| 857 | float incr = 0.5; |
| 858 | while (incr > 1.0/1024.0) { |
| 859 | complex earlyP = interpolatePoint(rxBurst,earlyIndex); |
| 860 | complex lateP = interpolatePoint(rxBurst,lateIndex); |
| 861 | if (earlyP < lateP) |
| 862 | earlyIndex += incr; |
| 863 | else if (earlyP > lateP) |
| 864 | earlyIndex -= incr; |
| 865 | else break; |
| 866 | incr /= 2.0; |
| 867 | lateIndex = earlyIndex + 2.0; |
| 868 | } |
| 869 | |
| 870 | maxIndex = earlyIndex + 1.0; |
| 871 | maxVal = interpolatePoint(rxBurst,maxIndex); |
| 872 | |
| 873 | if (peakIndex!=NULL) |
| 874 | *peakIndex = maxIndex; |
| 875 | |
| 876 | if (avgPwr!=NULL) |
| 877 | *avgPwr = (sumPower-maxVal.norm2()) / (rxBurst.size()-1); |
| 878 | |
| 879 | return maxVal; |
| 880 | |
| 881 | } |
| 882 | |
| 883 | void scaleVector(signalVector &x, |
| 884 | complex scale) |
| 885 | { |
| 886 | signalVector::iterator xP = x.begin(); |
| 887 | signalVector::iterator xPEnd = x.end(); |
| 888 | if (!x.isRealOnly()) { |
| 889 | while (xP < xPEnd) { |
| 890 | *xP = *xP * scale; |
| 891 | xP++; |
| 892 | } |
| 893 | } |
| 894 | else { |
| 895 | while (xP < xPEnd) { |
| 896 | *xP = xP->real() * scale; |
| 897 | xP++; |
| 898 | } |
| 899 | } |
| 900 | } |
| 901 | |
| 902 | /** in-place conjugation */ |
| 903 | void conjugateVector(signalVector &x) |
| 904 | { |
| 905 | if (x.isRealOnly()) return; |
| 906 | signalVector::iterator xP = x.begin(); |
| 907 | signalVector::iterator xPEnd = x.end(); |
| 908 | while (xP < xPEnd) { |
| 909 | *xP = xP->conj(); |
| 910 | xP++; |
| 911 | } |
| 912 | } |
| 913 | |
| 914 | |
| 915 | // in-place addition!! |
| 916 | bool addVector(signalVector &x, |
| 917 | signalVector &y) |
| 918 | { |
| 919 | signalVector::iterator xP = x.begin(); |
| 920 | signalVector::iterator yP = y.begin(); |
| 921 | signalVector::iterator xPEnd = x.end(); |
| 922 | signalVector::iterator yPEnd = y.end(); |
| 923 | while ((xP < xPEnd) && (yP < yPEnd)) { |
| 924 | *xP = *xP + *yP; |
| 925 | xP++; yP++; |
| 926 | } |
| 927 | return true; |
| 928 | } |
| 929 | |
| 930 | // in-place multiplication!! |
| 931 | bool multVector(signalVector &x, |
| 932 | signalVector &y) |
| 933 | { |
| 934 | signalVector::iterator xP = x.begin(); |
| 935 | signalVector::iterator yP = y.begin(); |
| 936 | signalVector::iterator xPEnd = x.end(); |
| 937 | signalVector::iterator yPEnd = y.end(); |
| 938 | while ((xP < xPEnd) && (yP < yPEnd)) { |
| 939 | *xP = (*xP) * (*yP); |
| 940 | xP++; yP++; |
| 941 | } |
| 942 | return true; |
| 943 | } |
| 944 | |
| 945 | |
| 946 | void offsetVector(signalVector &x, |
| 947 | complex offset) |
| 948 | { |
| 949 | signalVector::iterator xP = x.begin(); |
| 950 | signalVector::iterator xPEnd = x.end(); |
| 951 | if (!x.isRealOnly()) { |
| 952 | while (xP < xPEnd) { |
| 953 | *xP += offset; |
| 954 | xP++; |
| 955 | } |
| 956 | } |
| 957 | else { |
| 958 | while (xP < xPEnd) { |
| 959 | *xP = xP->real() + offset; |
| 960 | xP++; |
| 961 | } |
| 962 | } |
| 963 | } |
| 964 | |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 965 | bool generateMidamble(int sps, int tsc) |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 966 | { |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 967 | bool status = true; |
| 968 | complex *data = NULL; |
| 969 | signalVector *autocorr = NULL, *midamble = NULL; |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 970 | signalVector *midMidamble = NULL, *_midMidamble = NULL; |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 971 | |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 972 | if ((tsc < 0) || (tsc > 7)) |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 973 | return false; |
| 974 | |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 975 | delete gMidambles[tsc]; |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 976 | |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 977 | /* Use middle 16 bits of each TSC. Correlation sequence is not pulse shaped */ |
| 978 | midMidamble = modulateBurst(gTrainingSequence[tsc].segment(5,16), 0, sps, true); |
| 979 | if (!midMidamble) |
| 980 | return false; |
| 981 | |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 982 | /* Simulated receive sequence is pulse shaped */ |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 983 | midamble = modulateBurst(gTrainingSequence[tsc], 0, sps, false); |
| 984 | if (!midamble) { |
| 985 | status = false; |
| 986 | goto release; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 987 | } |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 988 | |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 989 | // NOTE: Because ideal TSC 16-bit midamble is 66 symbols into burst, |
| 990 | // the ideal TSC has an + 180 degree phase shift, |
| 991 | // due to the pi/2 frequency shift, that |
| 992 | // needs to be accounted for. |
| 993 | // 26-midamble is 61 symbols into burst, has +90 degree phase shift. |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 994 | scaleVector(*midMidamble, complex(-1.0, 0.0)); |
| 995 | scaleVector(*midamble, complex(0.0, 1.0)); |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 996 | |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 997 | conjugateVector(*midMidamble); |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 998 | |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 999 | /* For SSE alignment, reallocate the midamble sequence on 16-byte boundary */ |
| 1000 | data = (complex *) convolve_h_alloc(midMidamble->size()); |
| 1001 | _midMidamble = new signalVector(data, 0, midMidamble->size()); |
| 1002 | _midMidamble->setAligned(true); |
| 1003 | memcpy(_midMidamble->begin(), midMidamble->begin(), |
| 1004 | midMidamble->size() * sizeof(complex)); |
| 1005 | |
| 1006 | autocorr = convolve(midamble, _midMidamble, NULL, NO_DELAY); |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 1007 | if (!autocorr) { |
| 1008 | status = false; |
| 1009 | goto release; |
| 1010 | } |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1011 | |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 1012 | gMidambles[tsc] = new CorrelationSequence; |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1013 | gMidambles[tsc]->buffer = data; |
| 1014 | gMidambles[tsc]->sequence = _midMidamble; |
| 1015 | gMidambles[tsc]->gain = peakDetect(*autocorr,&gMidambles[tsc]->TOA, NULL); |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1016 | |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 1017 | release: |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1018 | delete autocorr; |
| 1019 | delete midamble; |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1020 | delete midMidamble; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1021 | |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 1022 | if (!status) { |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1023 | delete _midMidamble; |
| 1024 | free(data); |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 1025 | gMidambles[tsc] = NULL; |
| 1026 | } |
| 1027 | |
| 1028 | return status; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1029 | } |
| 1030 | |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 1031 | bool generateRACHSequence(int sps) |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1032 | { |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 1033 | bool status = true; |
| 1034 | complex *data = NULL; |
| 1035 | signalVector *autocorr = NULL; |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1036 | signalVector *seq0 = NULL, *seq1 = NULL, *_seq1 = NULL; |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 1037 | |
| 1038 | delete gRACHSequence; |
| 1039 | |
| 1040 | seq0 = modulateBurst(gRACHSynchSequence, 0, sps, false); |
| 1041 | if (!seq0) |
| 1042 | return false; |
| 1043 | |
| 1044 | seq1 = modulateBurst(gRACHSynchSequence.segment(0, 40), 0, sps, true); |
| 1045 | if (!seq1) { |
| 1046 | status = false; |
| 1047 | goto release; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1048 | } |
| 1049 | |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 1050 | conjugateVector(*seq1); |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1051 | |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1052 | /* For SSE alignment, reallocate the midamble sequence on 16-byte boundary */ |
| 1053 | data = (complex *) convolve_h_alloc(seq1->size()); |
| 1054 | _seq1 = new signalVector(data, 0, seq1->size()); |
| 1055 | _seq1->setAligned(true); |
| 1056 | memcpy(_seq1->begin(), seq1->begin(), seq1->size() * sizeof(complex)); |
| 1057 | |
| 1058 | autocorr = convolve(seq0, _seq1, autocorr, NO_DELAY); |
| 1059 | if (!autocorr) { |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 1060 | status = false; |
| 1061 | goto release; |
| 1062 | } |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1063 | |
| 1064 | gRACHSequence = new CorrelationSequence; |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1065 | gRACHSequence->sequence = _seq1; |
| 1066 | gRACHSequence->buffer = data; |
| 1067 | gRACHSequence->gain = peakDetect(*autocorr,&gRACHSequence->TOA, NULL); |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 1068 | |
| 1069 | release: |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1070 | delete autocorr; |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 1071 | delete seq0; |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1072 | delete seq1; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1073 | |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 1074 | if (!status) { |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1075 | delete _seq1; |
| 1076 | free(data); |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 1077 | gRACHSequence = NULL; |
| 1078 | } |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1079 | |
Thomas Tsou | d6ed8c0 | 2013-08-20 16:27:12 -0400 | [diff] [blame] | 1080 | return status; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1081 | } |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1082 | |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1083 | static float computePeakRatio(signalVector *corr, |
| 1084 | int sps, float toa, complex amp) |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1085 | { |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1086 | int num = 0; |
| 1087 | complex *peak; |
| 1088 | float rms, avg = 0.0; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1089 | |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1090 | peak = corr->begin() + (int) rint(toa); |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1091 | |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1092 | /* Check for bogus results */ |
| 1093 | if ((toa < 0.0) || (toa > corr->size())) |
| 1094 | return 0.0; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1095 | |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1096 | for (int i = 2 * sps; i <= 5 * sps; i++) { |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1097 | if (peak - i >= corr->begin()) { |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1098 | avg += (peak - i)->norm2(); |
| 1099 | num++; |
| 1100 | } |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1101 | if (peak + i < corr->end()) { |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1102 | avg += (peak + i)->norm2(); |
| 1103 | num++; |
| 1104 | } |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1105 | } |
| 1106 | |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1107 | if (num < 2) |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1108 | return 0.0; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1109 | |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1110 | rms = sqrtf(avg / (float) num) + 0.00001; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1111 | |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1112 | return (amp.abs()) / rms; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1113 | } |
| 1114 | |
| 1115 | bool energyDetect(signalVector &rxBurst, |
| 1116 | unsigned windowLength, |
| 1117 | float detectThreshold, |
| 1118 | float *avgPwr) |
| 1119 | { |
| 1120 | |
| 1121 | signalVector::const_iterator windowItr = rxBurst.begin(); //+rxBurst.size()/2 - 5*windowLength/2; |
| 1122 | float energy = 0.0; |
| 1123 | if (windowLength < 0) windowLength = 20; |
| 1124 | if (windowLength > rxBurst.size()) windowLength = rxBurst.size(); |
| 1125 | for (unsigned i = 0; i < windowLength; i++) { |
| 1126 | energy += windowItr->norm2(); |
| 1127 | windowItr+=4; |
| 1128 | } |
| 1129 | if (avgPwr) *avgPwr = energy/windowLength; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1130 | return (energy/windowLength > detectThreshold*detectThreshold); |
| 1131 | } |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1132 | |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1133 | /* |
| 1134 | * Detect a burst based on correlation and peak-to-average ratio. Perform |
| 1135 | * fast peak detection (no interpolation) for initial gating. Interpolate |
| 1136 | * the sub-sample peak after we have detected the burst. |
| 1137 | */ |
| 1138 | static int detectBurst(signalVector &burst, |
| 1139 | signalVector &corr, CorrelationSequence *sync, |
| 1140 | float thresh, int sps, complex *amp, float *toa, |
| 1141 | int start, int len) |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1142 | { |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1143 | /* Correlate */ |
| 1144 | if (!convolve(&burst, sync->sequence, &corr, |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1145 | CUSTOM, start, len, sps, 0)) { |
Alexander Chemeris | 0b8aa00 | 2013-09-06 00:35:57 +0400 | [diff] [blame] | 1146 | #ifndef TRX_LOAD_TESTING |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1147 | return -1; |
Alexander Chemeris | 0b8aa00 | 2013-09-06 00:35:57 +0400 | [diff] [blame] | 1148 | #endif |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1149 | } |
| 1150 | |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1151 | /* Peak detection - place restrictions at correlation edges */ |
| 1152 | *amp = fastPeakDetect(corr, toa); |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1153 | |
Alexander Chemeris | 0b8aa00 | 2013-09-06 00:35:57 +0400 | [diff] [blame] | 1154 | #ifndef TRX_LOAD_TESTING |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1155 | if ((*toa < 3 * sps) || (*toa > len - 3 * sps)) |
| 1156 | return 0; |
Alexander Chemeris | 0b8aa00 | 2013-09-06 00:35:57 +0400 | [diff] [blame] | 1157 | #endif |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1158 | |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1159 | /* Peak -to-average ratio */ |
Alexander Chemeris | 0b8aa00 | 2013-09-06 00:35:57 +0400 | [diff] [blame] | 1160 | if (computePeakRatio(&corr, sps, *toa, *amp) < thresh) { |
| 1161 | #ifndef TRX_LOAD_TESTING |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1162 | return 0; |
Alexander Chemeris | 0b8aa00 | 2013-09-06 00:35:57 +0400 | [diff] [blame] | 1163 | #endif |
| 1164 | } |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1165 | |
| 1166 | /* Run the full peak detection when we have a burst */ |
| 1167 | *amp = peakDetect(corr, toa, NULL); |
| 1168 | |
| 1169 | /* Normalize our channel gain */ |
| 1170 | *amp = *amp / sync->gain; |
| 1171 | |
| 1172 | return 1; |
| 1173 | } |
| 1174 | |
| 1175 | /* |
| 1176 | * RACH burst detection |
| 1177 | * |
| 1178 | * Correlation window parameters: |
| 1179 | * target: Tail bits + RACH length (reduced from 41 to a multiple of 4) |
| 1180 | * head: Search 4 symbols before target |
| 1181 | * tail: Search 8 symbols after target |
| 1182 | */ |
| 1183 | int detectRACHBurst(signalVector &rxBurst, |
| 1184 | float thresh, |
| 1185 | int sps, |
| 1186 | complex *amp, |
| 1187 | float *toa) |
| 1188 | { |
| 1189 | int rc, start, target, head, tail, len; |
| 1190 | float _toa; |
| 1191 | complex _amp; |
| 1192 | signalVector corr; |
| 1193 | CorrelationSequence *sync; |
| 1194 | |
| 1195 | if ((sps != 1) && (sps != 2) && (sps != 4)) |
| 1196 | return -1; |
| 1197 | |
| 1198 | target = 8 + 40; |
| 1199 | head = 4; |
| 1200 | tail = 8; |
| 1201 | |
| 1202 | start = (target - head) * sps - 1; |
| 1203 | len = (head + tail) * sps; |
| 1204 | sync = gRACHSequence; |
| 1205 | corr = signalVector(len); |
| 1206 | |
| 1207 | rc = detectBurst(rxBurst, corr, sync, |
| 1208 | thresh, sps, &_amp, &_toa, start, len); |
| 1209 | if (rc < 0) { |
| 1210 | return -1; |
| 1211 | } else if (!rc) { |
| 1212 | if (amp) |
| 1213 | *amp = 0.0f; |
| 1214 | if (toa) |
| 1215 | *toa = 0.0f; |
| 1216 | return 0; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1217 | } |
| 1218 | |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1219 | /* Subtract forward search bits from delay */ |
| 1220 | if (toa) |
| 1221 | *toa = _toa - head * sps; |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 1222 | |
| 1223 | /* Compensate for unknown rotation */ |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1224 | if (amp) |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 1225 | *amp = _amp * complex(0.0, 1.0); |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1226 | |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1227 | return 1; |
| 1228 | } |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1229 | |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1230 | /* |
| 1231 | * Normal burst detection |
| 1232 | * |
| 1233 | * Correlation window parameters: |
| 1234 | * target: Tail + data + mid-midamble + 1/2 remaining midamblebits |
| 1235 | * head: Search 4 symbols before target |
| 1236 | * tail: Search 6 symbols + maximum expected delay |
| 1237 | */ |
| 1238 | int analyzeTrafficBurst(signalVector &rxBurst, unsigned tsc, float thresh, |
| 1239 | int sps, complex *amp, float *toa, unsigned max_toa, |
| 1240 | bool chan_req, signalVector **chan, float *chan_offset) |
| 1241 | { |
| 1242 | int rc, start, target, head, tail, len; |
| 1243 | complex _amp; |
| 1244 | float _toa; |
| 1245 | signalVector corr, *_chan; |
| 1246 | CorrelationSequence *sync; |
| 1247 | |
| 1248 | if ((tsc < 0) || (tsc > 7) || ((sps != 1) && (sps != 2) && (sps != 4))) |
| 1249 | return -1; |
| 1250 | |
| 1251 | target = 3 + 58 + 16 + 5; |
| 1252 | head = 4; |
| 1253 | tail = 6 + max_toa; |
| 1254 | |
| 1255 | start = (target - head) * sps - 1; |
| 1256 | len = (head + tail) * sps; |
| 1257 | sync = gMidambles[tsc]; |
| 1258 | corr = signalVector(len); |
| 1259 | |
| 1260 | rc = detectBurst(rxBurst, corr, sync, |
| 1261 | thresh, sps, &_amp, &_toa, start, len); |
| 1262 | if (rc < 0) { |
| 1263 | return -1; |
| 1264 | } else if (!rc) { |
| 1265 | if (amp) |
| 1266 | *amp = 0.0f; |
| 1267 | if (toa) |
| 1268 | *toa = 0.0f; |
| 1269 | return 0; |
| 1270 | } |
| 1271 | |
| 1272 | /* Subtract forward search bits from delay */ |
| 1273 | _toa -= head * sps; |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1274 | if (toa) |
| 1275 | *toa = _toa; |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 1276 | |
| 1277 | /* Compensate for unknown rotation */ |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1278 | if (amp) |
Thomas Tsou | 3e24f79 | 2013-09-05 05:08:09 -0400 | [diff] [blame] | 1279 | *amp = _amp * complex(0, 1.0); |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1280 | |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1281 | /* Equalization not currently supported */ |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1282 | if (chan_req) { |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1283 | *chan = new signalVector(6 * sps); |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1284 | |
| 1285 | if (chan_offset) |
Thomas Tsou | ef7c258 | 2013-08-21 20:58:00 -0400 | [diff] [blame] | 1286 | *chan_offset = 0.0; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1287 | } |
| 1288 | |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1289 | return 1; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1290 | } |
| 1291 | |
| 1292 | signalVector *decimateVector(signalVector &wVector, |
| 1293 | int decimationFactor) |
| 1294 | { |
| 1295 | |
| 1296 | if (decimationFactor <= 1) return NULL; |
| 1297 | |
| 1298 | signalVector *decVector = new signalVector(wVector.size()/decimationFactor); |
| 1299 | decVector->isRealOnly(wVector.isRealOnly()); |
| 1300 | |
| 1301 | signalVector::iterator vecItr = decVector->begin(); |
| 1302 | for (unsigned int i = 0; i < wVector.size();i+=decimationFactor) |
| 1303 | *vecItr++ = wVector[i]; |
| 1304 | |
| 1305 | return decVector; |
| 1306 | } |
| 1307 | |
| 1308 | |
Thomas Tsou | c8ce878 | 2013-09-02 13:51:11 +0800 | [diff] [blame] | 1309 | SoftVector *demodulateBurst(signalVector &rxBurst, int sps, |
| 1310 | complex channel, float TOA) |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1311 | { |
| 1312 | scaleVector(rxBurst,((complex) 1.0)/channel); |
| 1313 | delayVector(rxBurst,-TOA); |
| 1314 | |
| 1315 | signalVector *shapedBurst = &rxBurst; |
| 1316 | |
| 1317 | // shift up by a quarter of a frequency |
| 1318 | // ignore starting phase, since spec allows for discontinuous phase |
| 1319 | GMSKReverseRotate(*shapedBurst); |
| 1320 | |
| 1321 | // run through slicer |
Thomas Tsou | e01e1b3 | 2013-09-02 13:24:13 +0800 | [diff] [blame] | 1322 | if (sps > 1) { |
| 1323 | signalVector *decShapedBurst = decimateVector(*shapedBurst, sps); |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1324 | shapedBurst = decShapedBurst; |
| 1325 | } |
| 1326 | |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1327 | vectorSlicer(shapedBurst); |
| 1328 | |
| 1329 | SoftVector *burstBits = new SoftVector(shapedBurst->size()); |
| 1330 | |
| 1331 | SoftVector::iterator burstItr = burstBits->begin(); |
| 1332 | signalVector::iterator shapedItr = shapedBurst->begin(); |
| 1333 | for (; shapedItr < shapedBurst->end(); shapedItr++) |
| 1334 | *burstItr++ = shapedItr->real(); |
| 1335 | |
Thomas Tsou | e01e1b3 | 2013-09-02 13:24:13 +0800 | [diff] [blame] | 1336 | if (sps > 1) |
| 1337 | delete shapedBurst; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1338 | |
| 1339 | return burstBits; |
| 1340 | |
| 1341 | } |
| 1342 | |
| 1343 | |
| 1344 | // 1.0 is sampling frequency |
| 1345 | // must satisfy cutoffFreq > 1/filterLen |
| 1346 | signalVector *createLPF(float cutoffFreq, |
| 1347 | int filterLen, |
| 1348 | float gainDC) |
| 1349 | { |
kurtis.heimerl | a198d45 | 2011-11-26 03:19:28 +0000 | [diff] [blame] | 1350 | #if 0 |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1351 | signalVector *LPF = new signalVector(filterLen-1); |
| 1352 | LPF->isRealOnly(true); |
| 1353 | LPF->setSymmetry(ABSSYM); |
| 1354 | signalVector::iterator itr = LPF->begin(); |
| 1355 | double sum = 0.0; |
| 1356 | for (int i = 1; i < filterLen; i++) { |
| 1357 | float ys = sinc(M_2PI_F*cutoffFreq*((float)i-(float)(filterLen)/2.0F)); |
| 1358 | float yg = 4.0F * cutoffFreq; |
| 1359 | // Blackman -- less brickwall (sloping transition) but larger stopband attenuation |
| 1360 | float yw = 0.42 - 0.5*cos(((float)i)*M_2PI_F/(float)(filterLen)) + 0.08*cos(((float)i)*2*M_2PI_F/(float)(filterLen)); |
| 1361 | // Hamming -- more brickwall with smaller stopband attenuation |
| 1362 | //float yw = 0.53836F - 0.46164F * cos(((float)i)*M_2PI_F/(float)(filterLen+1)); |
| 1363 | *itr++ = (complex) ys*yg*yw; |
| 1364 | sum += ys*yg*yw; |
| 1365 | } |
kurtis.heimerl | a198d45 | 2011-11-26 03:19:28 +0000 | [diff] [blame] | 1366 | #else |
| 1367 | double sum = 0.0; |
| 1368 | signalVector *LPF; |
| 1369 | signalVector::iterator itr; |
| 1370 | if (filterLen == 651) { // receive LPF |
| 1371 | LPF = new signalVector(651); |
| 1372 | LPF->isRealOnly(true); |
| 1373 | itr = LPF->begin(); |
| 1374 | for (int i = 0; i < filterLen; i++) { |
| 1375 | *itr++ = complex(rcvLPF_651[i],0.0); |
| 1376 | sum += rcvLPF_651[i]; |
| 1377 | } |
| 1378 | } |
| 1379 | else { |
| 1380 | LPF = new signalVector(961); |
| 1381 | LPF->isRealOnly(true); |
| 1382 | itr = LPF->begin(); |
| 1383 | for (int i = 0; i < filterLen; i++) { |
| 1384 | *itr++ = complex(sendLPF_961[i],0.0); |
| 1385 | sum += sendLPF_961[i]; |
| 1386 | } |
| 1387 | } |
| 1388 | #endif |
| 1389 | |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1390 | float normFactor = gainDC/sum; //sqrtf(gainDC/vectorNorm2(*LPF)); |
| 1391 | // normalize power |
| 1392 | itr = LPF->begin(); |
kurtis.heimerl | a198d45 | 2011-11-26 03:19:28 +0000 | [diff] [blame] | 1393 | for (int i = 0; i < filterLen; i++) { |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1394 | *itr = *itr*normFactor; |
| 1395 | itr++; |
| 1396 | } |
| 1397 | return LPF; |
| 1398 | |
| 1399 | } |
| 1400 | |
| 1401 | |
| 1402 | |
| 1403 | #define POLYPHASESPAN 10 |
| 1404 | |
| 1405 | // assumes filter group delay is 0.5*(length of filter) |
| 1406 | signalVector *polyphaseResampleVector(signalVector &wVector, |
| 1407 | int P, int Q, |
| 1408 | signalVector *LPF) |
| 1409 | |
| 1410 | { |
| 1411 | |
| 1412 | bool deleteLPF = false; |
| 1413 | |
| 1414 | if (LPF==NULL) { |
| 1415 | float cutoffFreq = (P < Q) ? (1.0/(float) Q) : (1.0/(float) P); |
| 1416 | LPF = createLPF(cutoffFreq/3.0,100*POLYPHASESPAN+1,Q); |
| 1417 | deleteLPF = true; |
| 1418 | } |
| 1419 | |
| 1420 | signalVector *resampledVector = new signalVector((int) ceil(wVector.size()*(float) P / (float) Q)); |
| 1421 | resampledVector->fill(0); |
| 1422 | resampledVector->isRealOnly(wVector.isRealOnly()); |
| 1423 | signalVector::iterator newItr = resampledVector->begin(); |
| 1424 | |
| 1425 | //FIXME: need to update for real-only vectors |
| 1426 | int outputIx = (LPF->size()+1)/2/Q; //((P > Q) ? P : Q); |
| 1427 | while (newItr < resampledVector->end()) { |
| 1428 | int outputBranch = (outputIx*Q) % P; |
| 1429 | int inputOffset = (outputIx*Q - outputBranch)/P; |
| 1430 | signalVector::const_iterator inputItr = wVector.begin() + inputOffset; |
| 1431 | signalVector::const_iterator filtItr = LPF->begin() + outputBranch; |
| 1432 | while (inputItr >= wVector.end()) { |
| 1433 | inputItr--; |
| 1434 | filtItr+=P; |
| 1435 | } |
| 1436 | complex sum = 0.0; |
| 1437 | if ((LPF->getSymmetry()!=ABSSYM) || (P>1)) { |
| 1438 | if (!LPF->isRealOnly()) { |
| 1439 | while ( (inputItr >= wVector.begin()) && (filtItr < LPF->end()) ) { |
| 1440 | sum += (*inputItr)*(*filtItr); |
| 1441 | inputItr--; |
| 1442 | filtItr += P; |
| 1443 | } |
| 1444 | } |
| 1445 | else { |
| 1446 | while ( (inputItr >= wVector.begin()) && (filtItr < LPF->end()) ) { |
| 1447 | sum += (*inputItr)*(filtItr->real()); |
| 1448 | inputItr--; |
| 1449 | filtItr += P; |
| 1450 | } |
| 1451 | } |
| 1452 | } |
| 1453 | else { |
| 1454 | signalVector::const_iterator revInputItr = inputItr- LPF->size() + 1; |
| 1455 | signalVector::const_iterator filtMidpoint = LPF->begin()+(LPF->size()-1)/2; |
| 1456 | if (!LPF->isRealOnly()) { |
| 1457 | while (filtItr <= filtMidpoint) { |
| 1458 | if (inputItr < revInputItr) break; |
| 1459 | if (inputItr == revInputItr) |
| 1460 | sum += (*inputItr)*(*filtItr); |
| 1461 | else if ( (inputItr < wVector.end()) && (revInputItr >= wVector.begin()) ) |
| 1462 | sum += (*inputItr + *revInputItr)*(*filtItr); |
| 1463 | else if ( inputItr < wVector.end() ) |
| 1464 | sum += (*inputItr)*(*filtItr); |
| 1465 | else if ( revInputItr >= wVector.begin() ) |
| 1466 | sum += (*revInputItr)*(*filtItr); |
| 1467 | inputItr--; |
| 1468 | revInputItr++; |
| 1469 | filtItr++; |
| 1470 | } |
| 1471 | } |
| 1472 | else { |
| 1473 | while (filtItr <= filtMidpoint) { |
| 1474 | if (inputItr < revInputItr) break; |
| 1475 | if (inputItr == revInputItr) |
| 1476 | sum += (*inputItr)*(filtItr->real()); |
| 1477 | else if ( (inputItr < wVector.end()) && (revInputItr >= wVector.begin()) ) |
| 1478 | sum += (*inputItr + *revInputItr)*(filtItr->real()); |
| 1479 | else if ( inputItr < wVector.end() ) |
| 1480 | sum += (*inputItr)*(filtItr->real()); |
| 1481 | else if ( revInputItr >= wVector.begin() ) |
| 1482 | sum += (*revInputItr)*(filtItr->real()); |
| 1483 | inputItr--; |
| 1484 | revInputItr++; |
| 1485 | filtItr++; |
| 1486 | } |
| 1487 | } |
| 1488 | } |
| 1489 | *newItr = sum; |
| 1490 | newItr++; |
| 1491 | outputIx++; |
| 1492 | } |
| 1493 | |
| 1494 | if (deleteLPF) delete LPF; |
| 1495 | |
| 1496 | return resampledVector; |
| 1497 | } |
| 1498 | |
| 1499 | |
| 1500 | signalVector *resampleVector(signalVector &wVector, |
| 1501 | float expFactor, |
| 1502 | complex endPoint) |
| 1503 | |
| 1504 | { |
| 1505 | |
| 1506 | if (expFactor < 1.0) return NULL; |
| 1507 | |
| 1508 | signalVector *retVec = new signalVector((int) ceil(wVector.size()*expFactor)); |
| 1509 | |
| 1510 | float t = 0.0; |
| 1511 | |
| 1512 | signalVector::iterator retItr = retVec->begin(); |
| 1513 | while (retItr < retVec->end()) { |
| 1514 | unsigned tLow = (unsigned int) floor(t); |
| 1515 | unsigned tHigh = tLow + 1; |
| 1516 | if (tLow > wVector.size()-1) break; |
| 1517 | if (tHigh > wVector.size()) break; |
| 1518 | complex lowPoint = wVector[tLow]; |
| 1519 | complex highPoint = (tHigh == wVector.size()) ? endPoint : wVector[tHigh]; |
| 1520 | complex a = (tHigh-t); |
| 1521 | complex b = (t-tLow); |
| 1522 | *retItr = (a*lowPoint + b*highPoint); |
| 1523 | t += 1.0/expFactor; |
| 1524 | } |
| 1525 | |
| 1526 | return retVec; |
| 1527 | |
| 1528 | } |
| 1529 | |
| 1530 | |
| 1531 | // Assumes symbol-spaced sampling!!! |
| 1532 | // Based upon paper by Al-Dhahir and Cioffi |
| 1533 | bool designDFE(signalVector &channelResponse, |
| 1534 | float SNRestimate, |
| 1535 | int Nf, |
| 1536 | signalVector **feedForwardFilter, |
| 1537 | signalVector **feedbackFilter) |
| 1538 | { |
| 1539 | |
| 1540 | signalVector G0(Nf); |
| 1541 | signalVector G1(Nf); |
| 1542 | signalVector::iterator G0ptr = G0.begin(); |
| 1543 | signalVector::iterator G1ptr = G1.begin(); |
| 1544 | signalVector::iterator chanPtr = channelResponse.begin(); |
| 1545 | |
| 1546 | int nu = channelResponse.size()-1; |
| 1547 | |
| 1548 | *G0ptr = 1.0/sqrtf(SNRestimate); |
| 1549 | for(int j = 0; j <= nu; j++) { |
| 1550 | *G1ptr = chanPtr->conj(); |
| 1551 | G1ptr++; chanPtr++; |
| 1552 | } |
| 1553 | |
| 1554 | signalVector *L[Nf]; |
| 1555 | signalVector::iterator Lptr; |
| 1556 | float d; |
| 1557 | for(int i = 0; i < Nf; i++) { |
| 1558 | d = G0.begin()->norm2() + G1.begin()->norm2(); |
| 1559 | L[i] = new signalVector(Nf+nu); |
| 1560 | Lptr = L[i]->begin()+i; |
| 1561 | G0ptr = G0.begin(); G1ptr = G1.begin(); |
| 1562 | while ((G0ptr < G0.end()) && (Lptr < L[i]->end())) { |
| 1563 | *Lptr = (*G0ptr*(G0.begin()->conj()) + *G1ptr*(G1.begin()->conj()) )/d; |
| 1564 | Lptr++; |
| 1565 | G0ptr++; |
| 1566 | G1ptr++; |
| 1567 | } |
| 1568 | complex k = (*G1.begin())/(*G0.begin()); |
| 1569 | |
| 1570 | if (i != Nf-1) { |
| 1571 | signalVector G0new = G1; |
| 1572 | scaleVector(G0new,k.conj()); |
| 1573 | addVector(G0new,G0); |
| 1574 | |
| 1575 | signalVector G1new = G0; |
| 1576 | scaleVector(G1new,k*(-1.0)); |
| 1577 | addVector(G1new,G1); |
| 1578 | delayVector(G1new,-1.0); |
| 1579 | |
| 1580 | scaleVector(G0new,1.0/sqrtf(1.0+k.norm2())); |
| 1581 | scaleVector(G1new,1.0/sqrtf(1.0+k.norm2())); |
| 1582 | G0 = G0new; |
| 1583 | G1 = G1new; |
| 1584 | } |
| 1585 | } |
| 1586 | |
| 1587 | *feedbackFilter = new signalVector(nu); |
| 1588 | L[Nf-1]->segmentCopyTo(**feedbackFilter,Nf,nu); |
| 1589 | scaleVector(**feedbackFilter,(complex) -1.0); |
| 1590 | conjugateVector(**feedbackFilter); |
| 1591 | |
| 1592 | signalVector v(Nf); |
| 1593 | signalVector::iterator vStart = v.begin(); |
| 1594 | signalVector::iterator vPtr; |
| 1595 | *(vStart+Nf-1) = (complex) 1.0; |
| 1596 | for(int k = Nf-2; k >= 0; k--) { |
| 1597 | Lptr = L[k]->begin()+k+1; |
| 1598 | vPtr = vStart + k+1; |
| 1599 | complex v_k = 0.0; |
| 1600 | for (int j = k+1; j < Nf; j++) { |
| 1601 | v_k -= (*vPtr)*(*Lptr); |
| 1602 | vPtr++; Lptr++; |
| 1603 | } |
| 1604 | *(vStart + k) = v_k; |
| 1605 | } |
| 1606 | |
| 1607 | *feedForwardFilter = new signalVector(Nf); |
Thomas Tsou | 0c260ae | 2013-08-22 18:40:43 -0400 | [diff] [blame] | 1608 | signalVector::iterator w = (*feedForwardFilter)->end(); |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1609 | for (int i = 0; i < Nf; i++) { |
| 1610 | delete L[i]; |
| 1611 | complex w_i = 0.0; |
| 1612 | int endPt = ( nu < (Nf-1-i) ) ? nu : (Nf-1-i); |
| 1613 | vPtr = vStart+i; |
| 1614 | chanPtr = channelResponse.begin(); |
| 1615 | for (int k = 0; k < endPt+1; k++) { |
| 1616 | w_i += (*vPtr)*(chanPtr->conj()); |
| 1617 | vPtr++; chanPtr++; |
| 1618 | } |
Thomas Tsou | 0c260ae | 2013-08-22 18:40:43 -0400 | [diff] [blame] | 1619 | *--w = w_i/d; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1620 | } |
| 1621 | |
| 1622 | |
| 1623 | return true; |
| 1624 | |
| 1625 | } |
| 1626 | |
| 1627 | // Assumes symbol-rate sampling!!!! |
| 1628 | SoftVector *equalizeBurst(signalVector &rxBurst, |
| 1629 | float TOA, |
Thomas Tsou | e01e1b3 | 2013-09-02 13:24:13 +0800 | [diff] [blame] | 1630 | int sps, |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1631 | signalVector &w, // feedforward filter |
| 1632 | signalVector &b) // feedback filter |
| 1633 | { |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1634 | signalVector *postForwardFull; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1635 | |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1636 | if (!delayVector(rxBurst, -TOA)) |
| 1637 | return NULL; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1638 | |
Thomas Tsou | acc9ee9 | 2013-08-20 19:31:14 -0400 | [diff] [blame] | 1639 | postForwardFull = convolve(&rxBurst, &w, NULL, |
| 1640 | CUSTOM, 0, rxBurst.size() + w.size() - 1); |
| 1641 | if (!postForwardFull) |
| 1642 | return NULL; |
dburgess | b3a0ca4 | 2011-10-12 07:44:40 +0000 | [diff] [blame] | 1643 | |
| 1644 | signalVector* postForward = new signalVector(rxBurst.size()); |
| 1645 | postForwardFull->segmentCopyTo(*postForward,w.size()-1,rxBurst.size()); |
| 1646 | delete postForwardFull; |
| 1647 | |
| 1648 | signalVector::iterator dPtr = postForward->begin(); |
| 1649 | signalVector::iterator dBackPtr; |
| 1650 | signalVector::iterator rotPtr = GMSKRotation->begin(); |
| 1651 | signalVector::iterator revRotPtr = GMSKReverseRotation->begin(); |
| 1652 | |
| 1653 | signalVector *DFEoutput = new signalVector(postForward->size()); |
| 1654 | signalVector::iterator DFEItr = DFEoutput->begin(); |
| 1655 | |
| 1656 | // NOTE: can insert the midamble and/or use midamble to estimate BER |
| 1657 | for (; dPtr < postForward->end(); dPtr++) { |
| 1658 | dBackPtr = dPtr-1; |
| 1659 | signalVector::iterator bPtr = b.begin(); |
| 1660 | while ( (bPtr < b.end()) && (dBackPtr >= postForward->begin()) ) { |
| 1661 | *dPtr = *dPtr + (*bPtr)*(*dBackPtr); |
| 1662 | bPtr++; |
| 1663 | dBackPtr--; |
| 1664 | } |
| 1665 | *dPtr = *dPtr * (*revRotPtr); |
| 1666 | *DFEItr = *dPtr; |
| 1667 | // make decision on symbol |
| 1668 | *dPtr = (dPtr->real() > 0.0) ? 1.0 : -1.0; |
| 1669 | //*DFEItr = *dPtr; |
| 1670 | *dPtr = *dPtr * (*rotPtr); |
| 1671 | DFEItr++; |
| 1672 | rotPtr++; |
| 1673 | revRotPtr++; |
| 1674 | } |
| 1675 | |
| 1676 | vectorSlicer(DFEoutput); |
| 1677 | |
| 1678 | SoftVector *burstBits = new SoftVector(postForward->size()); |
| 1679 | SoftVector::iterator burstItr = burstBits->begin(); |
| 1680 | DFEItr = DFEoutput->begin(); |
| 1681 | for (; DFEItr < DFEoutput->end(); DFEItr++) |
| 1682 | *burstItr++ = DFEItr->real(); |
| 1683 | |
| 1684 | delete postForward; |
| 1685 | |
| 1686 | delete DFEoutput; |
| 1687 | |
| 1688 | return burstBits; |
| 1689 | } |