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-rw-r--r--Transceiver52M/radioInterfaceResamp.cpp332
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diff --git a/Transceiver52M/radioInterfaceResamp.cpp b/Transceiver52M/radioInterfaceResamp.cpp
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-/*
- * Radio device interface with sample rate conversion
- * Written by Thomas Tsou <ttsou@vt.edu>
- *
- * Copyright 2011 Free Software Foundation, Inc.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU Affero General Public License for more details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- * See the COPYING file in the main directory for details.
- */
-
-#include <radioInterface.h>
-#include <Logger.h>
-
-/* New chunk sizes for resampled rate */
-#ifdef INCHUNK
- #undef INCHUNK
-#endif
-#ifdef OUTCHUNK
- #undef OUTCHUNK
-#endif
-
-/* Resampling parameters */
-#define INRATE 65 * SAMPSPERSYM
-#define INHISTORY INRATE * 2
-#define INCHUNK INRATE * 9
-
-#define OUTRATE 96 * SAMPSPERSYM
-#define OUTHISTORY OUTRATE * 2
-#define OUTCHUNK OUTRATE * 9
-
-/* Resampler low pass filters */
-signalVector *tx_lpf = 0;
-signalVector *rx_lpf = 0;
-
-/* Resampler history */
-signalVector *tx_hist = 0;
-signalVector *rx_hist = 0;
-
-/* Resampler input buffer */
-signalVector *tx_vec = 0;
-signalVector *rx_vec = 0;
-
-/*
- * High rate (device facing) buffers
- *
- * Transmit side samples are pushed after each burst so accomodate
- * a resampled burst plus up to a chunk left over from the previous
- * resampling operation.
- *
- * Receive side samples always pulled with a fixed size.
- */
-short tx_buf[INCHUNK * 2 * 4];
-short rx_buf[OUTCHUNK * 2 * 2];
-
-/*
- * Utilities and Conversions
- *
- * Manipulate signal vectors dynamically for two reasons. For one,
- * it's simpler. And two, it doesn't make any reasonable difference
- * relative to the high overhead generated by the resampling.
- */
-
-/* Concatenate signal vectors. Deallocate input vectors. */
-signalVector *concat(signalVector *a, signalVector *b)
-{
- signalVector *vec = new signalVector(*a, *b);
- delete a;
- delete b;
-
- return vec;
-}
-
-/* Segment a signal vector. Deallocate the input vector. */
-signalVector *segment(signalVector *a, int indx, int sz)
-{
- signalVector *vec = new signalVector(sz);
- a->segmentCopyTo(*vec, indx, sz);
- delete a;
-
- return vec;
-}
-
-/* Create a new signal vector from a short array. */
-signalVector *short_to_sigvec(short *smpls, size_t sz)
-{
- int i;
- signalVector *vec = new signalVector(sz);
- signalVector::iterator itr = vec->begin();
-
- for (i = 0; i < sz; i++) {
- *itr++ = Complex<float>(smpls[2 * i + 0], smpls[2 * i + 1]);
- }
-
- return vec;
-}
-
-/* Convert and deallocate a signal vector into a short array. */
-int sigvec_to_short(signalVector *vec, short *smpls)
-{
- int i;
- signalVector::iterator itr = vec->begin();
-
- for (i = 0; i < vec->size(); i++) {
- smpls[2 * i + 0] = itr->real();
- smpls[2 * i + 1] = itr->imag();
- itr++;
- }
- delete vec;
-
- return i;
-}
-
-/* Create a new signal vector from a float array. */
-signalVector *float_to_sigvec(float *smpls, int sz)
-{
- int i;
- signalVector *vec = new signalVector(sz);
- signalVector::iterator itr = vec->begin();
-
- for (i = 0; i < sz; i++) {
- *itr++ = Complex<float>(smpls[2 * i + 0], smpls[2 * i + 1]);
- }
-
- return vec;
-}
-
-/* Convert and deallocate a signal vector into a float array. */
-int sigvec_to_float(signalVector *vec, float *smpls)
-{
- int i;
- signalVector::iterator itr = vec->begin();
-
- for (i = 0; i < vec->size(); i++) {
- smpls[2 * i + 0] = itr->real();
- smpls[2 * i + 1] = itr->imag();
- itr++;
- }
- delete vec;
-
- return i;
-}
-
-/* Initialize resampling signal vectors */
-void init_resampler(signalVector **lpf,
- signalVector **buf,
- signalVector **hist,
- int tx)
-{
- int P, Q, taps, hist_len;
- float cutoff_freq;
-
- if (tx) {
- LOG(INFO) << "Initializing Tx resampler";
- P = OUTRATE;
- Q = INRATE;
- taps = 651;
- hist_len = INHISTORY;
- } else {
- LOG(INFO) << "Initializing Rx resampler";
- P = INRATE;
- Q = OUTRATE;
- taps = 961;
- hist_len = OUTHISTORY;
- }
-
- if (!*lpf) {
- cutoff_freq = (P < Q) ? (1.0/(float) Q) : (1.0/(float) P);
- *lpf = createLPF(cutoff_freq, taps, P);
- }
-
- if (!*buf) {
- *buf = new signalVector();
- }
-
- if (!*hist);
- *hist = new signalVector(hist_len);
-}
-
-/* Resample a signal vector
- *
- * The input vector is deallocated and the pointer returned with a vector
- * of any unconverted samples.
- */
-signalVector *resmpl_sigvec(signalVector *hist, signalVector **vec,
- signalVector *lpf, double in_rate,
- double out_rate, int chunk_sz)
-{
- signalVector *resamp_vec;
- int num_chunks = (*vec)->size() / chunk_sz;
-
- /* Truncate to a chunk multiple */
- signalVector trunc_vec(num_chunks * chunk_sz);
- (*vec)->segmentCopyTo(trunc_vec, 0, num_chunks * chunk_sz);
-
- /* Update sample buffer with remainder */
- *vec = segment(*vec, trunc_vec.size(), (*vec)->size() - trunc_vec.size());
-
- /* Add history and resample */
- signalVector input_vec(*hist, trunc_vec);
- resamp_vec = polyphaseResampleVector(input_vec, in_rate,
- out_rate, lpf);
-
- /* Update history */
- trunc_vec.segmentCopyTo(*hist, trunc_vec.size() - hist->size(),
- hist->size());
- return resamp_vec;
-}
-
-/* Wrapper for receive-side integer-to-float array resampling */
- int rx_resmpl_int_flt(float *smpls_out, short *smpls_in, int num_smpls)
-{
- int num_resmpld, num_chunks;
- signalVector *convert_vec, *resamp_vec, *trunc_vec;
-
- if (!rx_lpf || !rx_vec || !rx_hist)
- init_resampler(&rx_lpf, &rx_vec, &rx_hist, false);
-
- /* Convert and add samples to the receive buffer */
- convert_vec = short_to_sigvec(smpls_in, num_smpls);
- rx_vec = concat(rx_vec, convert_vec);
-
- num_chunks = rx_vec->size() / OUTCHUNK;
- if (num_chunks < 1)
- return 0;
-
- /* Resample */
- resamp_vec = resmpl_sigvec(rx_hist, &rx_vec, rx_lpf,
- INRATE, OUTRATE, OUTCHUNK);
- /* Truncate */
- trunc_vec = segment(resamp_vec, INHISTORY,
- resamp_vec->size() - INHISTORY);
- /* Convert */
- num_resmpld = sigvec_to_float(trunc_vec, smpls_out);
-
- return num_resmpld;
-}
-
-/* Wrapper for transmit-side float-to-int array resampling */
-int tx_resmpl_flt_int(short *smpls_out, float *smpls_in, int num_smpls)
-{
- int num_resmpl, num_chunks;
- signalVector *convert_vec, *resamp_vec;
-
- if (!tx_lpf || !tx_vec || !tx_hist)
- init_resampler(&tx_lpf, &tx_vec, &tx_hist, true);
-
- /* Convert and add samples to the transmit buffer */
- convert_vec = float_to_sigvec(smpls_in, num_smpls);
- tx_vec = concat(tx_vec, convert_vec);
-
- num_chunks = tx_vec->size() / INCHUNK;
- if (num_chunks < 1)
- return 0;
-
- /* Resample and convert to an integer array */
- resamp_vec = resmpl_sigvec(tx_hist, &tx_vec, tx_lpf,
- OUTRATE, INRATE, INCHUNK);
- num_resmpl = sigvec_to_short(resamp_vec, smpls_out);
-
- return num_resmpl;
-}
-
-RadioInterfaceResamp::RadioInterfaceResamp(RadioDevice *wRadio,
- int wReceiveOffset,
- int wSPS,
- GSM::Time wStartTime)
- : RadioInterface(wRadio, wReceiveOffset, wSPS, wStartTime)
-{
-}
-
-/* Receive a timestamped chunk from the device */
-void RadioInterfaceResamp::pullBuffer()
-{
- int num_cv, num_rd;
- bool local_underrun;
-
- /* Read samples. Fail if we don't get what we want. */
- num_rd = mRadio->readSamples(rx_buf, OUTCHUNK, &overrun,
- readTimestamp, &local_underrun);
-
- LOG(DEBUG) << "Rx read " << num_rd << " samples from device";
- assert(num_rd == OUTCHUNK);
-
- underrun |= local_underrun;
- readTimestamp += (TIMESTAMP) num_rd;
-
- /* Convert and resample */
- num_cv = rx_resmpl_int_flt(rcvBuffer + 2 * rcvCursor,
- rx_buf, num_rd);
-
- LOG(DEBUG) << "Rx read " << num_cv << " samples from resampler";
-
- rcvCursor += num_cv;
-}
-
-/* Send a timestamped chunk to the device */
-void RadioInterfaceResamp::pushBuffer()
-{
- int num_cv, num_wr;
-
- if (sendCursor < INCHUNK)
- return;
-
- LOG(DEBUG) << "Tx wrote " << sendCursor << " samples to resampler";
-
- /* Resample and convert */
- num_cv = tx_resmpl_flt_int(tx_buf, sendBuffer, sendCursor);
- assert(num_cv > sendCursor);
-
- /* Write samples. Fail if we don't get what we want. */
- num_wr = mRadio->writeSamples(tx_buf + OUTHISTORY * 2,
- num_cv - OUTHISTORY,
- &underrun,
- writeTimestamp);
-
- LOG(DEBUG) << "Tx wrote " << num_wr << " samples to device";
- assert(num_wr == num_wr);
-
- writeTimestamp += (TIMESTAMP) num_wr;
- sendCursor = 0;
-}