sigproc: Remove normal burst DFE equalizer
DFE equalizer is unused and has been experiencing code rot for
multiple years. The effect is a significant amount of baggage being
carried in the Transceiver and interfaces.
Signed-off-by: Tom Tsou <tom.tsou@ettus.com>
diff --git a/Transceiver52M/sigProcLib.cpp b/Transceiver52M/sigProcLib.cpp
index de8b1cf..8786c4a 100644
--- a/Transceiver52M/sigProcLib.cpp
+++ b/Transceiver52M/sigProcLib.cpp
@@ -1485,8 +1485,7 @@
* tail: Search 4 symbols + maximum expected delay
*/
int analyzeTrafficBurst(signalVector &rxBurst, unsigned tsc, float thresh,
- int sps, complex &, float &toa, unsigned max_toa,
- bool chan_req, signalVector **chan, float *chan_offset)
+ int sps, complex &, float &toa, unsigned max_toa)
{
int rc, target, head, tail;
CorrelationSequence *sync;
@@ -1501,15 +1500,6 @@
rc = detectGeneralBurst(rxBurst, thresh, sps, amp, toa,
target, head, tail, sync);
-
- /* Equalization not currently supported */
- if (rc > 0 && chan_req) {
- *chan = new signalVector(6 * sps);
-
- if (chan_offset)
- *chan_offset = 0.0;
- }
-
return rc;
}
@@ -1566,166 +1556,6 @@
return bits;
}
-// 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 = 1.0;
- 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, &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, &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 = GMSKRotation4->begin();
- signalVector::iterator revRotPtr = GMSKReverseRotation4->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()
{
initTrigTables();