mirror of
https://github.com/RangeNetworks/openbts.git
synced 2025-11-04 05:43:14 +00:00
b2482baf79
Previous patch fdf71fb5 "Remove unused and unmaintained files" was
incomplete. Remove remaining use of sendLPF_961.h and rcvLPF_651.h.
Signed-off-by: Tom Tsou <tom.tsou@ettus.com>
1631 lines
39 KiB
C++
1631 lines
39 KiB
C++
/*
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* Copyright 2008, 2011 Free Software Foundation, Inc.
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*
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* This software is distributed under the terms of the GNU Affero Public License.
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* See the COPYING file in the main directory for details.
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*
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* This use of this software may be subject to additional restrictions.
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* See the LEGAL file in the main directory for details.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU Affero General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Affero General Public License for more details.
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You should have received a copy of the GNU Affero General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "sigProcLib.h"
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#include "GSMCommon.h"
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extern "C" {
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#include "convolve.h"
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}
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/* Clipping detection threshold */
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#define CLIP_THRESH 30000.0f
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#define TABLESIZE 1024
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/** Lookup tables for trigonometric approximation */
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float cosTable[TABLESIZE+1]; // add 1 element for wrap around
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float sinTable[TABLESIZE+1];
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/** Constants */
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static const float M_PI_F = (float)M_PI;
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static const float M_2PI_F = (float)(2.0*M_PI);
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static const float M_1_2PI_F = 1/M_2PI_F;
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/* Precomputed rotation vectors */
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static signalVector *GMSKRotationN = NULL;
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static signalVector *GMSKReverseRotationN = NULL;
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static signalVector *GMSKRotation1 = NULL;
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static signalVector *GMSKReverseRotation1 = NULL;
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/*
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* RACH and midamble correlation waveforms. Store the buffer separately
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* because we need to allocate it explicitly outside of the signal vector
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* constructor. This is because C++ (prior to C++11) is unable to natively
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* perform 16-byte memory alignment required by many SSE instructions.
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*/
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struct CorrelationSequence {
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CorrelationSequence() : sequence(NULL), buffer(NULL)
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{
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}
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~CorrelationSequence()
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{
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delete sequence;
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free(buffer);
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}
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signalVector *sequence;
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void *buffer;
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float toa;
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complex gain;
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};
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/*
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* Gaussian and empty modulation pulses. Like the correlation sequences,
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* store the runtime (Gaussian) buffer separately because of needed alignment
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* for SSE instructions.
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*/
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struct PulseSequence {
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PulseSequence() : c0(NULL), c1(NULL), empty(NULL),
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c0_buffer(NULL), c1_buffer(NULL)
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{
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}
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~PulseSequence()
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{
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delete c0;
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delete c1;
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delete empty;
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free(c0_buffer);
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free(c1_buffer);
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}
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signalVector *c0;
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signalVector *c1;
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signalVector *empty;
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void *c0_buffer;
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void *c1_buffer;
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};
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CorrelationSequence *gMidambles[] = {NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL};
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CorrelationSequence *gRACHSequence = NULL;
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PulseSequence *GSMPulse = NULL;
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PulseSequence *GSMPulse1 = NULL;
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void sigProcLibDestroy()
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{
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for (int i = 0; i < 8; i++) {
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delete gMidambles[i];
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gMidambles[i] = NULL;
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}
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delete GMSKRotationN;
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delete GMSKReverseRotationN;
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delete GMSKRotation1;
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delete GMSKReverseRotation1;
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delete gRACHSequence;
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delete GSMPulse;
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delete GSMPulse1;
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GMSKRotationN = NULL;
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GMSKRotation1 = NULL;
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GMSKReverseRotationN = NULL;
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GMSKReverseRotation1 = NULL;
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gRACHSequence = NULL;
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GSMPulse = NULL;
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GSMPulse1 = NULL;
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}
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// dB relative to 1.0.
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// if > 1.0, then return 0 dB
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float dB(float x) {
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float arg = 1.0F;
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float dB = 0.0F;
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if (x >= 1.0F) return 0.0F;
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if (x <= 0.0F) return -200.0F;
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float prevArg = arg;
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float prevdB = dB;
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float stepSize = 16.0F;
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float dBstepSize = 12.0F;
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while (stepSize > 1.0F) {
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do {
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prevArg = arg;
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prevdB = dB;
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arg /= stepSize;
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dB -= dBstepSize;
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} while (arg > x);
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arg = prevArg;
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dB = prevdB;
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stepSize *= 0.5F;
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dBstepSize -= 3.0F;
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}
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return ((arg-x)*(dB-3.0F) + (x-arg*0.5F)*dB)/(arg - arg*0.5F);
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}
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// 10^(-dB/10), inverse of dB func.
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float dBinv(float x) {
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float arg = 1.0F;
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float dB = 0.0F;
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if (x >= 0.0F) return 1.0F;
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if (x <= -200.0F) return 0.0F;
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float prevArg = arg;
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float prevdB = dB;
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float stepSize = 16.0F;
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float dBstepSize = 12.0F;
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while (stepSize > 1.0F) {
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do {
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prevArg = arg;
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prevdB = dB;
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arg /= stepSize;
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dB -= dBstepSize;
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} while (dB > x);
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arg = prevArg;
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dB = prevdB;
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stepSize *= 0.5F;
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dBstepSize -= 3.0F;
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}
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return ((dB-x)*(arg*0.5F)+(x-(dB-3.0F))*(arg))/3.0F;
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}
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float vectorNorm2(const signalVector &x)
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{
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signalVector::const_iterator xPtr = x.begin();
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float Energy = 0.0;
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for (;xPtr != x.end();xPtr++) {
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Energy += xPtr->norm2();
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}
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return Energy;
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}
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float vectorPower(const signalVector &x)
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{
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return vectorNorm2(x)/x.size();
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}
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/** compute cosine via lookup table */
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float cosLookup(const float x)
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{
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float arg = x*M_1_2PI_F;
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while (arg > 1.0F) arg -= 1.0F;
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while (arg < 0.0F) arg += 1.0F;
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const float argT = arg*((float)TABLESIZE);
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const int argI = (int)argT;
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const float delta = argT-argI;
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const float iDelta = 1.0F-delta;
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return iDelta*cosTable[argI] + delta*cosTable[argI+1];
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}
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/** compute sine via lookup table */
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float sinLookup(const float x)
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{
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float arg = x*M_1_2PI_F;
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while (arg > 1.0F) arg -= 1.0F;
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while (arg < 0.0F) arg += 1.0F;
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const float argT = arg*((float)TABLESIZE);
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const int argI = (int)argT;
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const float delta = argT-argI;
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const float iDelta = 1.0F-delta;
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return iDelta*sinTable[argI] + delta*sinTable[argI+1];
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}
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/** compute e^(-jx) via lookup table. */
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complex expjLookup(float x)
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{
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float arg = x*M_1_2PI_F;
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while (arg > 1.0F) arg -= 1.0F;
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while (arg < 0.0F) arg += 1.0F;
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const float argT = arg*((float)TABLESIZE);
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const int argI = (int)argT;
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const float delta = argT-argI;
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const float iDelta = 1.0F-delta;
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return complex(iDelta*cosTable[argI] + delta*cosTable[argI+1],
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iDelta*sinTable[argI] + delta*sinTable[argI+1]);
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}
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/** Library setup functions */
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void initTrigTables() {
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for (int i = 0; i < TABLESIZE+1; i++) {
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cosTable[i] = cos(2.0*M_PI*i/TABLESIZE);
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sinTable[i] = sin(2.0*M_PI*i/TABLESIZE);
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}
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}
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void initGMSKRotationTables(int sps)
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{
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GMSKRotationN = new signalVector(157 * sps);
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GMSKReverseRotationN = new signalVector(157 * sps);
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signalVector::iterator rotPtr = GMSKRotationN->begin();
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signalVector::iterator revPtr = GMSKReverseRotationN->begin();
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float phase = 0.0;
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while (rotPtr != GMSKRotationN->end()) {
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*rotPtr++ = expjLookup(phase);
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*revPtr++ = expjLookup(-phase);
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phase += M_PI_F / 2.0F / (float) sps;
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}
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GMSKRotation1 = new signalVector(157);
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GMSKReverseRotation1 = new signalVector(157);
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rotPtr = GMSKRotation1->begin();
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revPtr = GMSKReverseRotation1->begin();
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phase = 0.0;
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while (rotPtr != GMSKRotation1->end()) {
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*rotPtr++ = expjLookup(phase);
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*revPtr++ = expjLookup(-phase);
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phase += M_PI_F / 2.0F;
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}
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}
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static void GMSKRotate(signalVector &x, int sps)
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{
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signalVector::iterator rotPtr, xPtr = x.begin();
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if (sps == 1)
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rotPtr = GMSKRotation1->begin();
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else
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rotPtr = GMSKRotationN->begin();
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if (x.isRealOnly()) {
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while (xPtr < x.end()) {
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*xPtr = *rotPtr++ * (xPtr->real());
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xPtr++;
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}
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}
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else {
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while (xPtr < x.end()) {
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*xPtr = *rotPtr++ * (*xPtr);
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xPtr++;
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}
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}
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}
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static void GMSKReverseRotate(signalVector &x, int sps)
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{
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signalVector::iterator rotPtr, xPtr= x.begin();
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if (sps == 1)
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rotPtr = GMSKReverseRotation1->begin();
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else
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rotPtr = GMSKReverseRotationN->begin();
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if (x.isRealOnly()) {
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while (xPtr < x.end()) {
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*xPtr = *rotPtr++ * (xPtr->real());
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xPtr++;
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}
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}
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else {
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while (xPtr < x.end()) {
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*xPtr = *rotPtr++ * (*xPtr);
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xPtr++;
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}
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}
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}
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signalVector *convolve(const signalVector *x,
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const signalVector *h,
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signalVector *y,
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ConvType spanType, int start,
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unsigned len, unsigned step, int offset)
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{
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int rc, head = 0, tail = 0;
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bool alloc = false, append = false;
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const signalVector *_x = NULL;
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if (!x || !h)
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return NULL;
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switch (spanType) {
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case START_ONLY:
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start = 0;
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head = h->size();
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len = x->size();
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append = true;
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break;
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case NO_DELAY:
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start = h->size() / 2;
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head = start;
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tail = start;
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len = x->size();
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append = true;
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break;
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case CUSTOM:
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if (start < h->size() - 1) {
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head = h->size() - start;
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append = true;
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}
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if (start + len > x->size()) {
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tail = start + len - x->size();
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append = true;
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}
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break;
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default:
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return NULL;
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}
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/*
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* Error if the output vector is too small. Create the output vector
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* if the pointer is NULL.
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*/
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if (y && (len > y->size()))
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return NULL;
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if (!y) {
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y = new signalVector(len);
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alloc = true;
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}
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/* Prepend or post-pend the input vector if the parameters require it */
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if (append)
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_x = new signalVector(*x, head, tail);
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else
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_x = x;
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/*
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* Four convovle types:
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* 1. Complex-Real (aligned)
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* 2. Complex-Complex (aligned)
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* 3. Complex-Real (!aligned)
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* 4. Complex-Complex (!aligned)
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*/
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if (h->isRealOnly() && h->isAligned()) {
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rc = convolve_real((float *) _x->begin(), _x->size(),
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(float *) h->begin(), h->size(),
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(float *) y->begin(), y->size(),
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start, len, step, offset);
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} else if (!h->isRealOnly() && h->isAligned()) {
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rc = convolve_complex((float *) _x->begin(), _x->size(),
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(float *) h->begin(), h->size(),
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(float *) y->begin(), y->size(),
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start, len, step, offset);
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} else if (h->isRealOnly() && !h->isAligned()) {
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rc = base_convolve_real((float *) _x->begin(), _x->size(),
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(float *) h->begin(), h->size(),
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(float *) y->begin(), y->size(),
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start, len, step, offset);
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} else if (!h->isRealOnly() && !h->isAligned()) {
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rc = base_convolve_complex((float *) _x->begin(), _x->size(),
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(float *) h->begin(), h->size(),
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(float *) y->begin(), y->size(),
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start, len, step, offset);
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} else {
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rc = -1;
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}
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if (append)
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delete _x;
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if (rc < 0) {
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if (alloc)
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delete y;
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return NULL;
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}
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return y;
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}
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static bool generateC1Pulse(int sps, PulseSequence *pulse)
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{
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int len;
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if (!pulse)
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return false;
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switch (sps) {
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case 4:
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len = 8;
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break;
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default:
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return false;
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}
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pulse->c1_buffer = convolve_h_alloc(len);
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pulse->c1 = new signalVector((complex *)
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pulse->c1_buffer, 0, len);
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pulse->c1->isRealOnly(true);
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/* Enable alignment for SSE usage */
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pulse->c1->setAligned(true);
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signalVector::iterator xP = pulse->c1->begin();
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switch (sps) {
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case 4:
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/* BT = 0.30 */
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*xP++ = 0.0;
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*xP++ = 8.16373112e-03;
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*xP++ = 2.84385729e-02;
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*xP++ = 5.64158904e-02;
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*xP++ = 7.05463553e-02;
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*xP++ = 5.64158904e-02;
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*xP++ = 2.84385729e-02;
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*xP++ = 8.16373112e-03;
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}
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return true;
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}
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static PulseSequence *generateGSMPulse(int sps, int symbolLength)
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{
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int len;
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float arg, avg, center;
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PulseSequence *pulse;
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/* Store a single tap filter used for correlation sequence generation */
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pulse = new PulseSequence();
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pulse->empty = new signalVector(1);
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pulse->empty->isRealOnly(true);
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*(pulse->empty->begin()) = 1.0f;
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/*
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* For 4 samples-per-symbol use a precomputed single pulse Laurent
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* approximation. This should yields below 2 degrees of phase error at
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* the modulator output. Use the existing pulse approximation for all
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* other oversampling factors.
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*/
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switch (sps) {
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case 4:
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len = 16;
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break;
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default:
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len = sps * symbolLength;
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if (len < 4)
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len = 4;
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}
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pulse->c0_buffer = convolve_h_alloc(len);
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pulse->c0 = new signalVector((complex *) pulse->c0_buffer, 0, len);
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pulse->c0->isRealOnly(true);
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/* Enable alingnment for SSE usage */
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pulse->c0->setAligned(true);
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signalVector::iterator xP = pulse->c0->begin();
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if (sps == 4) {
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*xP++ = 0.0;
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*xP++ = 4.46348606e-03;
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*xP++ = 2.84385729e-02;
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*xP++ = 1.03184855e-01;
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*xP++ = 2.56065552e-01;
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*xP++ = 4.76375085e-01;
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*xP++ = 7.05961177e-01;
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*xP++ = 8.71291644e-01;
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*xP++ = 9.29453645e-01;
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*xP++ = 8.71291644e-01;
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*xP++ = 7.05961177e-01;
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*xP++ = 4.76375085e-01;
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*xP++ = 2.56065552e-01;
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*xP++ = 1.03184855e-01;
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*xP++ = 2.84385729e-02;
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*xP++ = 4.46348606e-03;
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generateC1Pulse(sps, pulse);
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} else {
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center = (float) (len - 1.0) / 2.0;
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|
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/* GSM pulse approximation */
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for (int i = 0; i < len; i++) {
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arg = ((float) i - center) / (float) sps;
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*xP++ = 0.96 * exp(-1.1380 * arg * arg -
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0.527 * arg * arg * arg * arg);
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}
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|
|
avg = sqrtf(vectorNorm2(*pulse->c0) / sps);
|
|
xP = pulse->c0->begin();
|
|
for (int i = 0; i < len; i++)
|
|
*xP++ /= avg;
|
|
}
|
|
|
|
return pulse;
|
|
}
|
|
|
|
signalVector* frequencyShift(signalVector *y,
|
|
signalVector *x,
|
|
float freq,
|
|
float startPhase,
|
|
float *finalPhase)
|
|
{
|
|
|
|
if (!x) return NULL;
|
|
|
|
if (y==NULL) {
|
|
y = new signalVector(x->size());
|
|
y->isRealOnly(x->isRealOnly());
|
|
if (y==NULL) return NULL;
|
|
}
|
|
|
|
if (y->size() < x->size()) return NULL;
|
|
|
|
float phase = startPhase;
|
|
signalVector::iterator yP = y->begin();
|
|
signalVector::iterator xPEnd = x->end();
|
|
signalVector::iterator xP = x->begin();
|
|
|
|
if (x->isRealOnly()) {
|
|
while (xP < xPEnd) {
|
|
(*yP++) = expjLookup(phase)*( (xP++)->real() );
|
|
phase += freq;
|
|
}
|
|
}
|
|
else {
|
|
while (xP < xPEnd) {
|
|
(*yP++) = (*xP++)*expjLookup(phase);
|
|
phase += freq;
|
|
}
|
|
}
|
|
|
|
|
|
if (finalPhase) *finalPhase = phase;
|
|
|
|
return y;
|
|
}
|
|
|
|
signalVector* reverseConjugate(signalVector *b)
|
|
{
|
|
signalVector *tmp = new signalVector(b->size());
|
|
tmp->isRealOnly(b->isRealOnly());
|
|
signalVector::iterator bP = b->begin();
|
|
signalVector::iterator bPEnd = b->end();
|
|
signalVector::iterator tmpP = tmp->end()-1;
|
|
if (!b->isRealOnly()) {
|
|
while (bP < bPEnd) {
|
|
*tmpP-- = bP->conj();
|
|
bP++;
|
|
}
|
|
}
|
|
else {
|
|
while (bP < bPEnd) {
|
|
*tmpP-- = bP->real();
|
|
bP++;
|
|
}
|
|
}
|
|
|
|
return tmp;
|
|
}
|
|
|
|
/* soft output slicer */
|
|
bool vectorSlicer(signalVector *x)
|
|
{
|
|
|
|
signalVector::iterator xP = x->begin();
|
|
signalVector::iterator xPEnd = x->end();
|
|
while (xP < xPEnd) {
|
|
*xP = (complex) (0.5*(xP->real()+1.0F));
|
|
if (xP->real() > 1.0) *xP = 1.0;
|
|
if (xP->real() < 0.0) *xP = 0.0;
|
|
xP++;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static signalVector *rotateBurst(const BitVector &wBurst,
|
|
int guardPeriodLength, int sps)
|
|
{
|
|
int burst_len;
|
|
signalVector *pulse, rotated, *shaped;
|
|
signalVector::iterator itr;
|
|
|
|
pulse = GSMPulse1->empty;
|
|
burst_len = sps * (wBurst.size() + guardPeriodLength);
|
|
rotated = signalVector(burst_len);
|
|
itr = rotated.begin();
|
|
|
|
for (unsigned i = 0; i < wBurst.size(); i++) {
|
|
*itr = 2.0 * (wBurst[i] & 0x01) - 1.0;
|
|
itr += sps;
|
|
}
|
|
|
|
GMSKRotate(rotated, sps);
|
|
rotated.isRealOnly(false);
|
|
|
|
/* Dummy filter operation */
|
|
shaped = convolve(&rotated, pulse, NULL, START_ONLY);
|
|
if (!shaped)
|
|
return NULL;
|
|
|
|
return shaped;
|
|
}
|
|
|
|
static signalVector *modulateBurstLaurent(const BitVector &bits,
|
|
int guard_len, int sps)
|
|
{
|
|
int burst_len;
|
|
float phase;
|
|
signalVector *c0_pulse, *c1_pulse, c0_burst, c1_burst, *c0_shaped, *c1_shaped;
|
|
signalVector::iterator c0_itr, c1_itr;
|
|
|
|
/*
|
|
* Apply before and after bits to reduce phase error at burst edges.
|
|
* Make sure there is enough room in the burst to accomodate all bits.
|
|
*/
|
|
if (guard_len < 4)
|
|
guard_len = 4;
|
|
|
|
c0_pulse = GSMPulse->c0;
|
|
c1_pulse = GSMPulse->c1;
|
|
|
|
burst_len = sps * (bits.size() + guard_len);
|
|
|
|
c0_burst = signalVector(burst_len);
|
|
c0_burst.isRealOnly(true);
|
|
c0_itr = c0_burst.begin();
|
|
|
|
c1_burst = signalVector(burst_len);
|
|
c1_burst.isRealOnly(true);
|
|
c1_itr = c1_burst.begin();
|
|
|
|
/* Padded differential start bits */
|
|
*c0_itr = 2.0 * (0x00 & 0x01) - 1.0;
|
|
c0_itr += sps;
|
|
|
|
/* Main burst bits */
|
|
for (unsigned i = 0; i < bits.size(); i++) {
|
|
*c0_itr = 2.0 * (bits[i] & 0x01) - 1.0;
|
|
c0_itr += sps;
|
|
}
|
|
|
|
/* Padded differential end bits */
|
|
*c0_itr = 2.0 * (0x01 & 0x01) - 1.0;
|
|
|
|
/* Generate C0 phase coefficients */
|
|
GMSKRotate(c0_burst, sps);
|
|
c0_burst.isRealOnly(false);
|
|
|
|
c0_itr = c0_burst.begin();
|
|
c0_itr += sps * 2;
|
|
c1_itr += sps * 2;
|
|
|
|
/* Start magic */
|
|
phase = 2.0 * ((0x01 & 0x01) ^ (0x01 & 0x01)) - 1.0;
|
|
*c1_itr = *c0_itr * Complex<float>(0, phase);
|
|
c0_itr += sps;
|
|
c1_itr += sps;
|
|
|
|
/* Generate C1 phase coefficients */
|
|
for (unsigned i = 2; i < bits.size(); i++) {
|
|
phase = 2.0 * ((bits[i - 1] & 0x01) ^ (bits[i - 2] & 0x01)) - 1.0;
|
|
*c1_itr = *c0_itr * Complex<float>(0, phase);
|
|
|
|
c0_itr += sps;
|
|
c1_itr += sps;
|
|
}
|
|
|
|
/* End magic */
|
|
int i = bits.size();
|
|
phase = 2.0 * ((bits[i-1] & 0x01) ^ (bits[i-2] & 0x01)) - 1.0;
|
|
*c1_itr = *c0_itr * Complex<float>(0, phase);
|
|
|
|
/* Primary (C0) and secondary (C1) pulse shaping */
|
|
c0_shaped = convolve(&c0_burst, c0_pulse, NULL, START_ONLY);
|
|
c1_shaped = convolve(&c1_burst, c1_pulse, NULL, START_ONLY);
|
|
|
|
/* Sum shaped outputs into C0 */
|
|
c0_itr = c0_shaped->begin();
|
|
c1_itr = c1_shaped->begin();
|
|
for (unsigned i = 0; i < c0_shaped->size(); i++ )
|
|
*c0_itr++ += *c1_itr++;
|
|
|
|
delete c1_shaped;
|
|
|
|
return c0_shaped;
|
|
}
|
|
|
|
static signalVector *modulateBurstBasic(const BitVector &bits,
|
|
int guard_len, int sps)
|
|
{
|
|
int burst_len;
|
|
signalVector *pulse, burst, *shaped;
|
|
signalVector::iterator burst_itr;
|
|
|
|
if (sps == 1)
|
|
pulse = GSMPulse1->c0;
|
|
else
|
|
pulse = GSMPulse->c0;
|
|
|
|
burst_len = sps * (bits.size() + guard_len);
|
|
|
|
burst = signalVector(burst_len);
|
|
burst.isRealOnly(true);
|
|
burst_itr = burst.begin();
|
|
|
|
/* Raw bits are not differentially encoded */
|
|
for (unsigned i = 0; i < bits.size(); i++) {
|
|
*burst_itr = 2.0 * (bits[i] & 0x01) - 1.0;
|
|
burst_itr += sps;
|
|
}
|
|
|
|
GMSKRotate(burst, sps);
|
|
burst.isRealOnly(false);
|
|
|
|
/* Single Gaussian pulse approximation shaping */
|
|
shaped = convolve(&burst, pulse, NULL, START_ONLY);
|
|
|
|
return shaped;
|
|
}
|
|
|
|
/* Assume input bits are not differentially encoded */
|
|
signalVector *modulateBurst(const BitVector &wBurst, int guardPeriodLength,
|
|
int sps, bool emptyPulse)
|
|
{
|
|
if (emptyPulse)
|
|
return rotateBurst(wBurst, guardPeriodLength, sps);
|
|
else if (sps == 4)
|
|
return modulateBurstLaurent(wBurst, guardPeriodLength, sps);
|
|
else
|
|
return modulateBurstBasic(wBurst, guardPeriodLength, sps);
|
|
}
|
|
|
|
float sinc(float x)
|
|
{
|
|
if ((x >= 0.01F) || (x <= -0.01F)) return (sinLookup(x)/x);
|
|
return 1.0F;
|
|
}
|
|
|
|
bool delayVector(signalVector &wBurst, float delay)
|
|
{
|
|
int whole, h_len = 20;
|
|
float frac;
|
|
complex *data;
|
|
signalVector *h, *shift;
|
|
signalVector::iterator itr;
|
|
|
|
whole = floor(delay);
|
|
frac = delay - whole;
|
|
|
|
/* Sinc interpolated fractional shift (if allowable) */
|
|
if (fabs(frac) > 1e-2) {
|
|
data = (complex *) convolve_h_alloc(h_len);
|
|
h = new signalVector(data, 0, h_len);
|
|
h->setAligned(true);
|
|
h->isRealOnly(true);
|
|
|
|
itr = h->end();
|
|
for (int i = 0; i < h_len; i++)
|
|
*--itr = (complex) sinc(M_PI_F * (i - h_len / 2 - frac));
|
|
|
|
shift = convolve(&wBurst, h, NULL, NO_DELAY);
|
|
|
|
delete h;
|
|
free(data);
|
|
|
|
if (!shift)
|
|
return false;
|
|
|
|
wBurst.clone(*shift);
|
|
delete shift;
|
|
}
|
|
|
|
/* Integer sample shift */
|
|
if (whole < 0) {
|
|
whole = -whole;
|
|
signalVector::iterator wBurstItr = wBurst.begin();
|
|
signalVector::iterator shiftedItr = wBurst.begin() + whole;
|
|
|
|
while (shiftedItr < wBurst.end())
|
|
*wBurstItr++ = *shiftedItr++;
|
|
while (wBurstItr < wBurst.end())
|
|
*wBurstItr++ = 0.0;
|
|
} else {
|
|
signalVector::iterator wBurstItr = wBurst.end() - 1;
|
|
signalVector::iterator shiftedItr = wBurst.end() - 1 - whole;
|
|
|
|
while (shiftedItr >= wBurst.begin())
|
|
*wBurstItr-- = *shiftedItr--;
|
|
while (wBurstItr >= wBurst.begin())
|
|
*wBurstItr-- = 0.0;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
signalVector *gaussianNoise(int length,
|
|
float variance,
|
|
complex mean)
|
|
{
|
|
|
|
signalVector *noise = new signalVector(length);
|
|
signalVector::iterator nPtr = noise->begin();
|
|
float stddev = sqrtf(variance);
|
|
while (nPtr < noise->end()) {
|
|
float u1 = (float) rand()/ (float) RAND_MAX;
|
|
while (u1==0.0)
|
|
u1 = (float) rand()/ (float) RAND_MAX;
|
|
float u2 = (float) rand()/ (float) RAND_MAX;
|
|
float arg = 2.0*M_PI*u2;
|
|
*nPtr = mean + stddev*complex(cos(arg),sin(arg))*sqrtf(-2.0*log(u1));
|
|
nPtr++;
|
|
}
|
|
|
|
return noise;
|
|
}
|
|
|
|
complex interpolatePoint(const signalVector &inSig,
|
|
float ix)
|
|
{
|
|
|
|
int start = (int) (floor(ix) - 10);
|
|
if (start < 0) start = 0;
|
|
int end = (int) (floor(ix) + 11);
|
|
if ((unsigned) end > inSig.size()-1) end = inSig.size()-1;
|
|
|
|
complex pVal = 0.0;
|
|
if (!inSig.isRealOnly()) {
|
|
for (int i = start; i < end; i++)
|
|
pVal += inSig[i] * sinc(M_PI_F*(i-ix));
|
|
}
|
|
else {
|
|
for (int i = start; i < end; i++)
|
|
pVal += inSig[i].real() * sinc(M_PI_F*(i-ix));
|
|
}
|
|
|
|
return pVal;
|
|
}
|
|
|
|
static complex fastPeakDetect(const signalVector &rxBurst, float *index)
|
|
{
|
|
float val, max = 0.0f;
|
|
complex amp;
|
|
int _index = -1;
|
|
|
|
for (int i = 0; i < rxBurst.size(); i++) {
|
|
val = rxBurst[i].norm2();
|
|
if (val > max) {
|
|
max = val;
|
|
_index = i;
|
|
amp = rxBurst[i];
|
|
}
|
|
}
|
|
|
|
if (index)
|
|
*index = (float) _index;
|
|
|
|
return amp;
|
|
}
|
|
|
|
complex peakDetect(const signalVector &rxBurst,
|
|
float *peakIndex,
|
|
float *avgPwr)
|
|
{
|
|
|
|
|
|
complex maxVal = 0.0;
|
|
float maxIndex = -1;
|
|
float sumPower = 0.0;
|
|
|
|
for (unsigned int i = 0; i < rxBurst.size(); i++) {
|
|
float samplePower = rxBurst[i].norm2();
|
|
if (samplePower > maxVal.real()) {
|
|
maxVal = samplePower;
|
|
maxIndex = i;
|
|
}
|
|
sumPower += samplePower;
|
|
}
|
|
|
|
// interpolate around the peak
|
|
// to save computation, we'll use early-late balancing
|
|
float earlyIndex = maxIndex-1;
|
|
float lateIndex = maxIndex+1;
|
|
|
|
float incr = 0.5;
|
|
while (incr > 1.0/1024.0) {
|
|
complex earlyP = interpolatePoint(rxBurst,earlyIndex);
|
|
complex lateP = interpolatePoint(rxBurst,lateIndex);
|
|
if (earlyP < lateP)
|
|
earlyIndex += incr;
|
|
else if (earlyP > lateP)
|
|
earlyIndex -= incr;
|
|
else break;
|
|
incr /= 2.0;
|
|
lateIndex = earlyIndex + 2.0;
|
|
}
|
|
|
|
maxIndex = earlyIndex + 1.0;
|
|
maxVal = interpolatePoint(rxBurst,maxIndex);
|
|
|
|
if (peakIndex!=NULL)
|
|
*peakIndex = maxIndex;
|
|
|
|
if (avgPwr!=NULL)
|
|
*avgPwr = (sumPower-maxVal.norm2()) / (rxBurst.size()-1);
|
|
|
|
return maxVal;
|
|
|
|
}
|
|
|
|
void scaleVector(signalVector &x,
|
|
complex scale)
|
|
{
|
|
signalVector::iterator xP = x.begin();
|
|
signalVector::iterator xPEnd = x.end();
|
|
if (!x.isRealOnly()) {
|
|
while (xP < xPEnd) {
|
|
*xP = *xP * scale;
|
|
xP++;
|
|
}
|
|
}
|
|
else {
|
|
while (xP < xPEnd) {
|
|
*xP = xP->real() * scale;
|
|
xP++;
|
|
}
|
|
}
|
|
}
|
|
|
|
/** in-place conjugation */
|
|
void conjugateVector(signalVector &x)
|
|
{
|
|
if (x.isRealOnly()) return;
|
|
signalVector::iterator xP = x.begin();
|
|
signalVector::iterator xPEnd = x.end();
|
|
while (xP < xPEnd) {
|
|
*xP = xP->conj();
|
|
xP++;
|
|
}
|
|
}
|
|
|
|
|
|
// in-place addition!!
|
|
bool addVector(signalVector &x,
|
|
signalVector &y)
|
|
{
|
|
signalVector::iterator xP = x.begin();
|
|
signalVector::iterator yP = y.begin();
|
|
signalVector::iterator xPEnd = x.end();
|
|
signalVector::iterator yPEnd = y.end();
|
|
while ((xP < xPEnd) && (yP < yPEnd)) {
|
|
*xP = *xP + *yP;
|
|
xP++; yP++;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
// in-place multiplication!!
|
|
bool multVector(signalVector &x,
|
|
signalVector &y)
|
|
{
|
|
signalVector::iterator xP = x.begin();
|
|
signalVector::iterator yP = y.begin();
|
|
signalVector::iterator xPEnd = x.end();
|
|
signalVector::iterator yPEnd = y.end();
|
|
while ((xP < xPEnd) && (yP < yPEnd)) {
|
|
*xP = (*xP) * (*yP);
|
|
xP++; yP++;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
|
|
void offsetVector(signalVector &x,
|
|
complex offset)
|
|
{
|
|
signalVector::iterator xP = x.begin();
|
|
signalVector::iterator xPEnd = x.end();
|
|
if (!x.isRealOnly()) {
|
|
while (xP < xPEnd) {
|
|
*xP += offset;
|
|
xP++;
|
|
}
|
|
}
|
|
else {
|
|
while (xP < xPEnd) {
|
|
*xP = xP->real() + offset;
|
|
xP++;
|
|
}
|
|
}
|
|
}
|
|
|
|
bool generateMidamble(int sps, int tsc)
|
|
{
|
|
bool status = true;
|
|
float toa;
|
|
complex *data = NULL;
|
|
signalVector *autocorr = NULL, *midamble = NULL;
|
|
signalVector *midMidamble = NULL, *_midMidamble = NULL;
|
|
|
|
if ((tsc < 0) || (tsc > 7))
|
|
return false;
|
|
|
|
delete gMidambles[tsc];
|
|
|
|
/* Use middle 16 bits of each TSC. Correlation sequence is not pulse shaped */
|
|
midMidamble = modulateBurst(gTrainingSequence[tsc].alias().segment(5,16), 0, sps, true);
|
|
if (!midMidamble)
|
|
return false;
|
|
|
|
/* Simulated receive sequence is pulse shaped */
|
|
midamble = modulateBurst(gTrainingSequence[tsc].alias(), 0, sps, false);
|
|
if (!midamble) {
|
|
status = false;
|
|
goto release;
|
|
}
|
|
|
|
// NOTE: Because ideal TSC 16-bit midamble is 66 symbols into burst,
|
|
// the ideal TSC has an + 180 degree phase shift,
|
|
// due to the pi/2 frequency shift, that
|
|
// needs to be accounted for.
|
|
// 26-midamble is 61 symbols into burst, has +90 degree phase shift.
|
|
scaleVector(*midMidamble, complex(-1.0, 0.0));
|
|
scaleVector(*midamble, complex(0.0, 1.0));
|
|
|
|
conjugateVector(*midMidamble);
|
|
|
|
/* For SSE alignment, reallocate the midamble sequence on 16-byte boundary */
|
|
data = (complex *) convolve_h_alloc(midMidamble->size());
|
|
_midMidamble = new signalVector(data, 0, midMidamble->size());
|
|
_midMidamble->setAligned(true);
|
|
memcpy(_midMidamble->begin(), midMidamble->begin(),
|
|
midMidamble->size() * sizeof(complex));
|
|
|
|
autocorr = convolve(midamble, _midMidamble, NULL, NO_DELAY);
|
|
if (!autocorr) {
|
|
status = false;
|
|
goto release;
|
|
}
|
|
|
|
gMidambles[tsc] = new CorrelationSequence;
|
|
gMidambles[tsc]->buffer = data;
|
|
gMidambles[tsc]->sequence = _midMidamble;
|
|
gMidambles[tsc]->gain = peakDetect(*autocorr, &toa, NULL);
|
|
|
|
/* For 1 sps only
|
|
* (Half of correlation length - 1) + midpoint of pulse shape + remainder
|
|
* 13.5 = (16 / 2 - 1) + 1.5 + (26 - 10) / 2
|
|
*/
|
|
if (sps == 1)
|
|
gMidambles[tsc]->toa = toa - 13.5;
|
|
else
|
|
gMidambles[tsc]->toa = 0;
|
|
|
|
release:
|
|
delete autocorr;
|
|
delete midamble;
|
|
delete midMidamble;
|
|
|
|
if (!status) {
|
|
delete _midMidamble;
|
|
free(data);
|
|
gMidambles[tsc] = NULL;
|
|
}
|
|
|
|
return status;
|
|
}
|
|
|
|
bool generateRACHSequence(int sps)
|
|
{
|
|
bool status = true;
|
|
float toa;
|
|
complex *data = NULL;
|
|
signalVector *autocorr = NULL;
|
|
signalVector *seq0 = NULL, *seq1 = NULL, *_seq1 = NULL;
|
|
|
|
delete gRACHSequence;
|
|
|
|
seq0 = modulateBurst(gRACHSynchSequence, 0, sps, false);
|
|
if (!seq0)
|
|
return false;
|
|
|
|
seq1 = modulateBurst(gRACHSynchSequence.alias().segment(0, 40), 0, sps, true);
|
|
if (!seq1) {
|
|
status = false;
|
|
goto release;
|
|
}
|
|
|
|
conjugateVector(*seq1);
|
|
|
|
/* For SSE alignment, reallocate the midamble sequence on 16-byte boundary */
|
|
data = (complex *) convolve_h_alloc(seq1->size());
|
|
_seq1 = new signalVector(data, 0, seq1->size());
|
|
_seq1->setAligned(true);
|
|
memcpy(_seq1->begin(), seq1->begin(), seq1->size() * sizeof(complex));
|
|
|
|
autocorr = convolve(seq0, _seq1, autocorr, NO_DELAY);
|
|
if (!autocorr) {
|
|
status = false;
|
|
goto release;
|
|
}
|
|
|
|
gRACHSequence = new CorrelationSequence;
|
|
gRACHSequence->sequence = _seq1;
|
|
gRACHSequence->buffer = data;
|
|
gRACHSequence->gain = peakDetect(*autocorr, &toa, NULL);
|
|
|
|
/* For 1 sps only
|
|
* (Half of correlation length - 1) + midpoint of pulse shaping filer
|
|
* 20.5 = (40 / 2 - 1) + 1.5
|
|
*/
|
|
if (sps == 1)
|
|
gRACHSequence->toa = toa - 20.5;
|
|
else
|
|
gRACHSequence->toa = 0.0;
|
|
|
|
release:
|
|
delete autocorr;
|
|
delete seq0;
|
|
delete seq1;
|
|
|
|
if (!status) {
|
|
delete _seq1;
|
|
free(data);
|
|
gRACHSequence = NULL;
|
|
}
|
|
|
|
return status;
|
|
}
|
|
|
|
static float computePeakRatio(signalVector *corr,
|
|
int sps, float toa, complex amp)
|
|
{
|
|
int num = 0;
|
|
complex *peak;
|
|
float rms, avg = 0.0;
|
|
|
|
peak = corr->begin() + (int) rint(toa);
|
|
|
|
/* Check for bogus results */
|
|
if ((toa < 0.0) || (toa > corr->size()))
|
|
return 0.0;
|
|
|
|
for (int i = 2 * sps; i <= 5 * sps; i++) {
|
|
if (peak - i >= corr->begin()) {
|
|
avg += (peak - i)->norm2();
|
|
num++;
|
|
}
|
|
if (peak + i < corr->end()) {
|
|
avg += (peak + i)->norm2();
|
|
num++;
|
|
}
|
|
}
|
|
|
|
if (num < 2)
|
|
return 0.0;
|
|
|
|
rms = sqrtf(avg / (float) num) + 0.00001;
|
|
|
|
return (amp.abs()) / rms;
|
|
}
|
|
|
|
bool energyDetect(signalVector &rxBurst,
|
|
unsigned windowLength,
|
|
float detectThreshold,
|
|
float *avgPwr)
|
|
{
|
|
|
|
signalVector::const_iterator windowItr = rxBurst.begin(); //+rxBurst.size()/2 - 5*windowLength/2;
|
|
float energy = 0.0;
|
|
if (windowLength < 0) windowLength = 20;
|
|
if (windowLength > rxBurst.size()) windowLength = rxBurst.size();
|
|
for (unsigned i = 0; i < windowLength; i++) {
|
|
energy += windowItr->norm2();
|
|
windowItr+=4;
|
|
}
|
|
if (avgPwr) *avgPwr = energy/windowLength;
|
|
return (energy/windowLength > detectThreshold*detectThreshold);
|
|
}
|
|
|
|
/*
|
|
* Detect a burst based on correlation and peak-to-average ratio
|
|
*
|
|
* For one sampler-per-symbol, perform fast peak detection (no interpolation)
|
|
* for initial gating. We do this because energy detection should be disabled.
|
|
* For higher oversampling values, we assume the energy detector is in place
|
|
* and we run full interpolating peak detection.
|
|
*/
|
|
static int detectBurst(signalVector &burst,
|
|
signalVector &corr, CorrelationSequence *sync,
|
|
float thresh, int sps, complex *amp, float *toa,
|
|
int start, int len)
|
|
{
|
|
/* Correlate */
|
|
if (!convolve(&burst, sync->sequence, &corr,
|
|
CUSTOM, start, len, sps, 0)) {
|
|
return -SIGERR_INTERNAL;
|
|
}
|
|
|
|
/* Peak detection - place restrictions at correlation edges */
|
|
*amp = fastPeakDetect(corr, toa);
|
|
|
|
if ((*toa < 3 * sps) || (*toa > len - 3 * sps))
|
|
return 0;
|
|
|
|
/* Peak -to-average ratio */
|
|
if (computePeakRatio(&corr, sps, *toa, *amp) < thresh)
|
|
return 0;
|
|
|
|
/* Compute peak-to-average ratio. Reject if we don't have enough values */
|
|
*amp = peakDetect(corr, toa, NULL);
|
|
|
|
/* Normalize our channel gain */
|
|
*amp = *amp / sync->gain;
|
|
|
|
/* Compenate for residual rotation with dual Laurent pulse */
|
|
if (sps == 4)
|
|
*amp = *amp * complex(0.0, 1.0);
|
|
|
|
/* Compensate for residuate time lag */
|
|
*toa = *toa - sync->toa;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int detectClipping(signalVector &burst, float thresh)
|
|
{
|
|
for (size_t i = 0; i < burst.size(); i++) {
|
|
if (fabs(burst[i].real()) > thresh)
|
|
return 1;
|
|
if (fabs(burst[i].imag()) > thresh)
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* RACH burst detection
|
|
*
|
|
* Correlation window parameters:
|
|
* target: Tail bits + RACH length (reduced from 41 to a multiple of 4)
|
|
* head: Search 4 symbols before target
|
|
* tail: Search 10 symbols after target
|
|
*/
|
|
int detectRACHBurst(signalVector &rxBurst,
|
|
float thresh,
|
|
int sps,
|
|
complex *amp,
|
|
float *toa)
|
|
{
|
|
int rc, start, target, head, tail, len;
|
|
float _toa;
|
|
complex _amp;
|
|
signalVector corr;
|
|
CorrelationSequence *sync;
|
|
|
|
if ((sps != 1) && (sps != 4))
|
|
return -SIGERR_UNSUPPORTED;
|
|
|
|
if (detectClipping(rxBurst, CLIP_THRESH))
|
|
return -SIGERR_CLIP;
|
|
|
|
target = 8 + 40;
|
|
head = 4;
|
|
tail = 10;
|
|
|
|
start = (target - head) * sps - 1;
|
|
len = (head + tail) * sps;
|
|
sync = gRACHSequence;
|
|
corr = signalVector(len);
|
|
|
|
rc = detectBurst(rxBurst, corr, sync,
|
|
thresh, sps, &_amp, &_toa, start, len);
|
|
if (rc < 0) {
|
|
return -1;
|
|
} else if (!rc) {
|
|
if (amp)
|
|
*amp = 0.0f;
|
|
if (toa)
|
|
*toa = 0.0f;
|
|
return 0;
|
|
}
|
|
|
|
/* Subtract forward search bits from delay */
|
|
if (toa)
|
|
*toa = _toa - head * sps;
|
|
if (amp)
|
|
*amp = _amp;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Normal burst detection
|
|
*
|
|
* Correlation window parameters:
|
|
* target: Tail + data + mid-midamble + 1/2 remaining midamblebits
|
|
* head: Search 4 symbols before target
|
|
* tail: Search 4 symbols + maximum expected delay
|
|
*/
|
|
int analyzeTrafficBurst(signalVector &rxBurst, unsigned tsc, float thresh,
|
|
int sps, complex *amp, float *toa, unsigned max_toa,
|
|
bool chan_req, signalVector **chan, float *chan_offset)
|
|
{
|
|
int rc, start, target, head, tail, len;
|
|
complex _amp;
|
|
float _toa;
|
|
signalVector corr;
|
|
CorrelationSequence *sync;
|
|
|
|
if ((tsc < 0) || (tsc > 7) || ((sps != 1) && (sps != 4)))
|
|
return -SIGERR_UNSUPPORTED;
|
|
|
|
target = 3 + 58 + 16 + 5;
|
|
head = 4;
|
|
tail = 4 + max_toa;
|
|
|
|
start = (target - head) * sps - 1;
|
|
len = (head + tail) * sps;
|
|
sync = gMidambles[tsc];
|
|
corr = signalVector(len);
|
|
|
|
rc = detectBurst(rxBurst, corr, sync,
|
|
thresh, sps, &_amp, &_toa, start, len);
|
|
if (rc < 0) {
|
|
return -SIGERR_INTERNAL;
|
|
} else if (!rc) {
|
|
if (amp)
|
|
*amp = 0.0f;
|
|
if (toa)
|
|
*toa = 0.0f;
|
|
return 0;
|
|
}
|
|
|
|
/* Subtract forward search bits from delay */
|
|
_toa -= head * sps;
|
|
if (toa)
|
|
*toa = _toa;
|
|
if (amp)
|
|
*amp = _amp;
|
|
|
|
/* Equalization not currently supported */
|
|
if (chan_req) {
|
|
*chan = new signalVector(6 * sps);
|
|
|
|
if (chan_offset)
|
|
*chan_offset = 0.0;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
signalVector *decimateVector(signalVector &wVector,
|
|
int decimationFactor)
|
|
{
|
|
|
|
if (decimationFactor <= 1) return NULL;
|
|
|
|
signalVector *decVector = new signalVector(wVector.size()/decimationFactor);
|
|
decVector->isRealOnly(wVector.isRealOnly());
|
|
|
|
signalVector::iterator vecItr = decVector->begin();
|
|
for (unsigned int i = 0; i < wVector.size();i+=decimationFactor)
|
|
*vecItr++ = wVector[i];
|
|
|
|
return decVector;
|
|
}
|
|
|
|
|
|
SoftVector *demodulateBurst(signalVector &rxBurst, int sps,
|
|
complex channel, float TOA)
|
|
{
|
|
scaleVector(rxBurst,((complex) 1.0)/channel);
|
|
delayVector(rxBurst,-TOA);
|
|
|
|
signalVector *shapedBurst = &rxBurst;
|
|
|
|
// shift up by a quarter of a frequency
|
|
// ignore starting phase, since spec allows for discontinuous phase
|
|
GMSKReverseRotate(*shapedBurst, sps);
|
|
|
|
// run through slicer
|
|
if (sps > 1) {
|
|
signalVector *decShapedBurst = decimateVector(*shapedBurst, sps);
|
|
shapedBurst = decShapedBurst;
|
|
}
|
|
|
|
vectorSlicer(shapedBurst);
|
|
|
|
SoftVector *burstBits = new SoftVector(shapedBurst->size());
|
|
|
|
SoftVector::iterator burstItr = burstBits->begin();
|
|
signalVector::iterator shapedItr = shapedBurst->begin();
|
|
for (; shapedItr < shapedBurst->end(); shapedItr++)
|
|
*burstItr++ = shapedItr->real();
|
|
|
|
if (sps > 1)
|
|
delete shapedBurst;
|
|
|
|
return burstBits;
|
|
|
|
}
|
|
|
|
// Assumes symbol-spaced sampling!!!
|
|
// Based upon paper by Al-Dhahir and Cioffi
|
|
bool designDFE(signalVector &channelResponse,
|
|
float SNRestimate,
|
|
int Nf,
|
|
signalVector **feedForwardFilter,
|
|
signalVector **feedbackFilter)
|
|
{
|
|
|
|
signalVector G0(Nf);
|
|
signalVector G1(Nf);
|
|
signalVector::iterator G0ptr = G0.begin();
|
|
signalVector::iterator G1ptr = G1.begin();
|
|
signalVector::iterator chanPtr = channelResponse.begin();
|
|
|
|
int nu = channelResponse.size()-1;
|
|
|
|
*G0ptr = 1.0/sqrtf(SNRestimate);
|
|
for(int j = 0; j <= nu; j++) {
|
|
*G1ptr = chanPtr->conj();
|
|
G1ptr++; chanPtr++;
|
|
}
|
|
|
|
signalVector *L[Nf];
|
|
signalVector::iterator Lptr;
|
|
float d;
|
|
for(int i = 0; i < Nf; i++) {
|
|
d = G0.begin()->norm2() + G1.begin()->norm2();
|
|
L[i] = new signalVector(Nf+nu);
|
|
Lptr = L[i]->begin()+i;
|
|
G0ptr = G0.begin(); G1ptr = G1.begin();
|
|
while ((G0ptr < G0.end()) && (Lptr < L[i]->end())) {
|
|
*Lptr = (*G0ptr*(G0.begin()->conj()) + *G1ptr*(G1.begin()->conj()) )/d;
|
|
Lptr++;
|
|
G0ptr++;
|
|
G1ptr++;
|
|
}
|
|
complex k = (*G1.begin())/(*G0.begin());
|
|
|
|
if (i != Nf-1) {
|
|
signalVector G0new = G1;
|
|
scaleVector(G0new,k.conj());
|
|
addVector(G0new,G0);
|
|
|
|
signalVector G1new = G0;
|
|
scaleVector(G1new,k*(-1.0));
|
|
addVector(G1new,G1);
|
|
delayVector(G1new,-1.0);
|
|
|
|
scaleVector(G0new,1.0/sqrtf(1.0+k.norm2()));
|
|
scaleVector(G1new,1.0/sqrtf(1.0+k.norm2()));
|
|
G0 = G0new;
|
|
G1 = G1new;
|
|
}
|
|
}
|
|
|
|
*feedbackFilter = new signalVector(nu);
|
|
L[Nf-1]->segmentCopyTo(**feedbackFilter,Nf,nu);
|
|
scaleVector(**feedbackFilter,(complex) -1.0);
|
|
conjugateVector(**feedbackFilter);
|
|
|
|
signalVector v(Nf);
|
|
signalVector::iterator vStart = v.begin();
|
|
signalVector::iterator vPtr;
|
|
*(vStart+Nf-1) = (complex) 1.0;
|
|
for(int k = Nf-2; k >= 0; k--) {
|
|
Lptr = L[k]->begin()+k+1;
|
|
vPtr = vStart + k+1;
|
|
complex v_k = 0.0;
|
|
for (int j = k+1; j < Nf; j++) {
|
|
v_k -= (*vPtr)*(*Lptr);
|
|
vPtr++; Lptr++;
|
|
}
|
|
*(vStart + k) = v_k;
|
|
}
|
|
|
|
*feedForwardFilter = new signalVector(Nf);
|
|
signalVector::iterator w = (*feedForwardFilter)->end();
|
|
for (int i = 0; i < Nf; i++) {
|
|
delete L[i];
|
|
complex w_i = 0.0;
|
|
int endPt = ( nu < (Nf-1-i) ) ? nu : (Nf-1-i);
|
|
vPtr = vStart+i;
|
|
chanPtr = channelResponse.begin();
|
|
for (int k = 0; k < endPt+1; k++) {
|
|
w_i += (*vPtr)*(chanPtr->conj());
|
|
vPtr++; chanPtr++;
|
|
}
|
|
*--w = w_i/d;
|
|
}
|
|
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
// Assumes symbol-rate sampling!!!!
|
|
SoftVector *equalizeBurst(signalVector &rxBurst,
|
|
float TOA,
|
|
int sps,
|
|
signalVector &w, // feedforward filter
|
|
signalVector &b) // feedback filter
|
|
{
|
|
signalVector *postForwardFull;
|
|
|
|
if (!delayVector(rxBurst, -TOA))
|
|
return NULL;
|
|
|
|
postForwardFull = convolve(&rxBurst, &w, NULL,
|
|
CUSTOM, 0, rxBurst.size() + w.size() - 1);
|
|
if (!postForwardFull)
|
|
return NULL;
|
|
|
|
signalVector* postForward = new signalVector(rxBurst.size());
|
|
postForwardFull->segmentCopyTo(*postForward,w.size()-1,rxBurst.size());
|
|
delete postForwardFull;
|
|
|
|
signalVector::iterator dPtr = postForward->begin();
|
|
signalVector::iterator dBackPtr;
|
|
signalVector::iterator rotPtr = GMSKRotationN->begin();
|
|
signalVector::iterator revRotPtr = GMSKReverseRotationN->begin();
|
|
|
|
signalVector *DFEoutput = new signalVector(postForward->size());
|
|
signalVector::iterator DFEItr = DFEoutput->begin();
|
|
|
|
// NOTE: can insert the midamble and/or use midamble to estimate BER
|
|
for (; dPtr < postForward->end(); dPtr++) {
|
|
dBackPtr = dPtr-1;
|
|
signalVector::iterator bPtr = b.begin();
|
|
while ( (bPtr < b.end()) && (dBackPtr >= postForward->begin()) ) {
|
|
*dPtr = *dPtr + (*bPtr)*(*dBackPtr);
|
|
bPtr++;
|
|
dBackPtr--;
|
|
}
|
|
*dPtr = *dPtr * (*revRotPtr);
|
|
*DFEItr = *dPtr;
|
|
// make decision on symbol
|
|
*dPtr = (dPtr->real() > 0.0) ? 1.0 : -1.0;
|
|
//*DFEItr = *dPtr;
|
|
*dPtr = *dPtr * (*rotPtr);
|
|
DFEItr++;
|
|
rotPtr++;
|
|
revRotPtr++;
|
|
}
|
|
|
|
vectorSlicer(DFEoutput);
|
|
|
|
SoftVector *burstBits = new SoftVector(postForward->size());
|
|
SoftVector::iterator burstItr = burstBits->begin();
|
|
DFEItr = DFEoutput->begin();
|
|
for (; DFEItr < DFEoutput->end(); DFEItr++)
|
|
*burstItr++ = DFEItr->real();
|
|
|
|
delete postForward;
|
|
|
|
delete DFEoutput;
|
|
|
|
return burstBits;
|
|
}
|
|
|
|
bool sigProcLibSetup(int sps)
|
|
{
|
|
if ((sps != 1) && (sps != 4))
|
|
return false;
|
|
|
|
initTrigTables();
|
|
initGMSKRotationTables(sps);
|
|
|
|
GSMPulse1 = generateGSMPulse(1, 2);
|
|
if (sps > 1)
|
|
GSMPulse = generateGSMPulse(sps, 2);
|
|
|
|
if (!generateRACHSequence(1)) {
|
|
sigProcLibDestroy();
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|