/** Initializes the phich channel receiver */
int srslte_phich_init(srslte_phich_t *q, srslte_regs_t *regs, srslte_cell_t cell) {
int ret = SRSLTE_ERROR_INVALID_INPUTS;
if (q != NULL &&
regs != NULL &&
srslte_cell_isvalid(&cell))
{
bzero(q, sizeof(srslte_phich_t));
ret = SRSLTE_ERROR;
q->cell = cell;
q->regs = regs;
if (srslte_precoding_init(&q->precoding, SRSLTE_SF_LEN_RE(cell.nof_prb, cell.cp))) {
fprintf(stderr, "Error initializing precoding\n");
}
if (srslte_modem_table_lte(&q->mod, SRSLTE_MOD_BPSK)) {
goto clean;
}
for (int nsf = 0; nsf < SRSLTE_NSUBFRAMES_X_FRAME; nsf++) {
if (srslte_sequence_phich(&q->seq[nsf], 2 * nsf, q->cell.id)) {
goto clean;
}
}
ret = SRSLTE_SUCCESS;
}
clean:
if (ret == SRSLTE_ERROR) {
srslte_phich_free(q);
}
return ret;
}
/** Initializes the pcfich channel receiver.
* On error, returns -1 and frees the structrure
*/
int srslte_pcfich_init(srslte_pcfich_t *q, srslte_regs_t *regs, srslte_cell_t cell) {
int ret = SRSLTE_ERROR_INVALID_INPUTS;
if (q != NULL &&
regs != NULL &&
srslte_cell_isvalid(&cell))
{
ret = SRSLTE_ERROR;
bzero(q, sizeof(srslte_pcfich_t));
q->cell = cell;
q->regs = regs;
q->nof_symbols = PCFICH_RE;
if (srslte_precoding_init(&q->precoding, SRSLTE_SF_LEN_RE(cell.nof_prb, cell.cp))) {
fprintf(stderr, "Error initializing precoding\n");
}
if (srslte_modem_table_lte(&q->mod, SRSLTE_MOD_QPSK)) {
goto clean;
}
for (int nsf = 0; nsf < SRSLTE_NSUBFRAMES_X_FRAME; nsf++) {
if (srslte_sequence_pcfich(&q->seq[nsf], 2 * nsf, q->cell.id)) {
goto clean;
}
}
/* convert cfi bit tables to floats for demodulation */
for (int i=0;i<3;i++) {
for (int j=0;j<PCFICH_CFI_LEN;j++) {
q->cfi_table_float[i][j] = (float) 2.0*cfi_table[i][j]-1.0;
}
}
ret = SRSLTE_SUCCESS;
}
clean:
if (ret == SRSLTE_ERROR) {
srslte_pcfich_free(q);
}
return ret;
}
/** Initializes the PDCCH transmitter and receiver */
int srslte_pdsch_init(srslte_pdsch_t *q, srslte_cell_t cell) {
int ret = SRSLTE_ERROR_INVALID_INPUTS;
int i;
if (q != NULL &&
srslte_cell_isvalid(&cell))
{
bzero(q, sizeof(srslte_pdsch_t));
ret = SRSLTE_ERROR;
q->cell = cell;
q->max_re = q->cell.nof_prb * MAX_PDSCH_RE(q->cell.cp);
INFO("Init PDSCH: %d ports %d PRBs, max_symbols: %d\n", q->cell.nof_ports,
q->cell.nof_prb, q->max_re);
if (srslte_precoding_init(&q->precoding, SRSLTE_SF_LEN_RE(cell.nof_prb, cell.cp))) {
fprintf(stderr, "Error initializing precoding\n");
goto clean;
}
for (i = 0; i < 4; i++) {
if (srslte_modem_table_lte(&q->mod[i], modulations[i])) {
goto clean;
}
srslte_modem_table_bytes(&q->mod[i]);
}
srslte_sch_init(&q->dl_sch);
q->rnti_is_set = false;
// Allocate int16_t for reception (LLRs)
q->e = srslte_vec_malloc(sizeof(int16_t) * q->max_re * srslte_mod_bits_x_symbol(SRSLTE_MOD_64QAM));
if (!q->e) {
goto clean;
}
q->d = srslte_vec_malloc(sizeof(cf_t) * q->max_re);
if (!q->d) {
goto clean;
}
for (i = 0; i < q->cell.nof_ports; i++) {
q->ce[i] = srslte_vec_malloc(sizeof(cf_t) * q->max_re);
if (!q->ce[i]) {
goto clean;
}
q->x[i] = srslte_vec_malloc(sizeof(cf_t) * q->max_re);
if (!q->x[i]) {
goto clean;
}
q->symbols[i] = srslte_vec_malloc(sizeof(cf_t) * q->max_re);
if (!q->symbols[i]) {
goto clean;
}
}
ret = SRSLTE_SUCCESS;
}
clean:
if (ret == SRSLTE_ERROR) {
srslte_pdsch_free(q);
}
return ret;
}
int main(int argc, char **argv) {
int i, j;
float mse;
cf_t *x[SRSLTE_MAX_LAYERS], *r[SRSLTE_MAX_PORTS], *y[SRSLTE_MAX_PORTS], *h[SRSLTE_MAX_PORTS],
*xr[SRSLTE_MAX_LAYERS];
srslte_mimo_type_t type;
srslte_precoding_t precoding;
parse_args(argc, argv);
if (nof_ports > SRSLTE_MAX_PORTS || nof_layers > SRSLTE_MAX_LAYERS) {
fprintf(stderr, "Invalid number of layers or ports\n");
exit(-1);
}
if (srslte_str2mimotype(mimo_type_name, &type)) {
fprintf(stderr, "Invalid MIMO type %s\n", mimo_type_name);
exit(-1);
}
for (i = 0; i < nof_layers; i++) {
x[i] = srslte_vec_malloc(sizeof(cf_t) * nof_symbols);
if (!x[i]) {
perror("srslte_vec_malloc");
exit(-1);
}
xr[i] = srslte_vec_malloc(sizeof(cf_t) * nof_symbols);
if (!xr[i]) {
perror("srslte_vec_malloc");
exit(-1);
}
}
for (i = 0; i < nof_ports; i++) {
y[i] = srslte_vec_malloc(sizeof(cf_t) * nof_symbols * nof_layers);
// TODO: The number of symbols per port is different in spatial multiplexing.
if (!y[i]) {
perror("srslte_vec_malloc");
exit(-1);
}
h[i] = srslte_vec_malloc(sizeof(cf_t) * nof_symbols * nof_layers);
if (!h[i]) {
perror("srslte_vec_malloc");
exit(-1);
}
}
/* only 1 receiver antenna supported now */
r[0] = srslte_vec_malloc(sizeof(cf_t) * nof_symbols * nof_layers);
if (!r[0]) {
perror("srslte_vec_malloc");
exit(-1);
}
/* generate random data */
for (i = 0; i < nof_layers; i++) {
for (j = 0; j < nof_symbols; j++) {
x[i][j] = (2*(rand()%2)-1+(2*(rand()%2)-1)*_Complex_I)/sqrt(2);
}
}
if (srslte_precoding_init(&precoding, nof_symbols * nof_layers)) {
fprintf(stderr, "Error initializing precoding\n");
exit(-1);
}
/* precoding */
if (srslte_precoding_type(&precoding, x, y, nof_layers, nof_ports, nof_symbols, type) < 0) {
fprintf(stderr, "Error layer mapper encoder\n");
exit(-1);
}
/* generate channel */
for (i = 0; i < nof_ports; i++) {
for (j = 0; j < nof_symbols; j++) {
h[i][nof_layers*j] = (float) rand()/RAND_MAX+((float) rand()/RAND_MAX)*_Complex_I;
// assume the channel is time-invariant in nlayer consecutive symbols
for (int k=0;k<nof_layers;k++) {
h[i][nof_layers*j+k] = h[i][nof_layers*j];
}
}
}
/* pass signal through channel
(we are in the frequency domain so it's a multiplication) */
/* there's only one receiver antenna, signals from different transmitter
* ports are simply combined at the receiver
*/
for (j = 0; j < nof_symbols * nof_layers; j++) {
r[0][j] = 0;
for (i = 0; i < nof_ports; i++) {
r[0][j] += y[i][j] * h[i][j];
}
}
/* predecoding / equalization */
struct timeval t[3];
gettimeofday(&t[1], NULL);
if (srslte_predecoding_type(&precoding, r[0], h, xr, nof_ports, nof_layers,
nof_symbols * nof_layers, type, 0) < 0) {
fprintf(stderr, "Error layer mapper encoder\n");
exit(-1);
}
gettimeofday(&t[2], NULL);
get_time_interval(t);
printf("Execution Time: %d us\n", t[0].tv_usec);
/* check errors */
mse = 0;
for (i = 0; i < nof_layers; i++) {
for (j = 0; j < nof_symbols; j++) {
mse += cabsf(xr[i][j] - x[i][j]);
}
}
printf("MSE: %f\n", mse/ nof_layers / nof_symbols );
if (mse / nof_layers / nof_symbols > MSE_THRESHOLD) {
exit(-1);
}
for (i = 0; i < nof_layers; i++) {
free(x[i]);
free(xr[i]);
}
for (i = 0; i < nof_ports; i++) {
free(y[i]);
free(h[i]);
}
free(r[0]);
srslte_precoding_free(&precoding);
printf("Ok\n");
exit(0);
}
/* the gateway function */
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
int i;
srslte_cell_t cell;
srslte_chest_dl_t chest;
srslte_precoding_t cheq;
cf_t *input_signal = NULL, *output_signal[SRSLTE_MAX_LAYERS];
cf_t *output_signal2 = NULL;
cf_t *ce[SRSLTE_MAX_PORTS];
double *outr0=NULL, *outi0=NULL;
double *outr1=NULL, *outi1=NULL;
double *outr2=NULL, *outi2=NULL;
if (!mxIsDouble(CELLID) && mxGetN(CELLID) != 1 &&
!mxIsDouble(PORTS) && mxGetN(PORTS) != 1 &&
mxGetM(CELLID) != 1) {
help();
return;
}
cell.id = (uint32_t) *((double*) mxGetPr(CELLID));
cell.nof_prb = mxGetM(INPUT)/SRSLTE_NRE;
cell.nof_ports = (uint32_t) *((double*) mxGetPr(PORTS));
if ((mxGetN(INPUT)%14) == 0) {
cell.cp = SRSLTE_CP_NORM;
} else if ((mxGetN(INPUT)%12)!=0) {
cell.cp = SRSLTE_CP_EXT;
} else {
mexErrMsgTxt("Invalid number of symbols\n");
help();
return;
}
if (srslte_chest_dl_init(&chest, cell)) {
mexErrMsgTxt("Error initiating channel estimator\n");
return;
}
int nsubframes;
if (cell.cp == SRSLTE_CP_NORM) {
nsubframes = mxGetN(INPUT)/14;
} else {
nsubframes = mxGetN(INPUT)/12;
}
uint32_t sf_idx=0;
if (nsubframes == 1) {
if (nrhs != NOF_INPUTS+1) {
mexErrMsgTxt("Received 1 subframe. Need to provide subframe index.\n");
help();
return;
}
sf_idx = (uint32_t) *((double*) mxGetPr(SFIDX));
}
if (nrhs > 5) {
uint32_t filter_len = 0;
float *filter;
double *f;
filter_len = mxGetNumberOfElements(FREQ_FILTER);
filter = malloc(sizeof(float) * filter_len);
f = (double*) mxGetPr(FREQ_FILTER);
for (i=0;i<filter_len;i++) {
filter[i] = (float) f[i];
}
srslte_chest_dl_set_filter_freq(&chest, filter, filter_len);
filter_len = mxGetNumberOfElements(TIME_FILTER);
filter = malloc(sizeof(float) * filter_len);
f = (double*) mxGetPr(TIME_FILTER);
for (i=0;i<filter_len;i++) {
filter[i] = (float) f[i];
}
srslte_chest_dl_set_filter_time(&chest, filter, filter_len);
}
double *inr=(double *)mxGetPr(INPUT);
double *ini=(double *)mxGetPi(INPUT);
/** Allocate input buffers */
int nof_re = 2*SRSLTE_CP_NSYMB(cell.cp)*cell.nof_prb*SRSLTE_NRE;
for (i=0;i<SRSLTE_MAX_PORTS;i++) {
ce[i] = srslte_vec_malloc(nof_re * sizeof(cf_t));
}
input_signal = srslte_vec_malloc(nof_re * sizeof(cf_t));
for (i=0;i<SRSLTE_MAX_PORTS;i++) {
output_signal[i] = srslte_vec_malloc(nof_re * sizeof(cf_t));
}
output_signal2 = srslte_vec_malloc(nof_re * sizeof(cf_t));
srslte_precoding_init(&cheq, nof_re);
/* Create output values */
if (nlhs >= 1) {
plhs[0] = mxCreateDoubleMatrix(nof_re * nsubframes, cell.nof_ports, mxCOMPLEX);
outr0 = mxGetPr(plhs[0]);
outi0 = mxGetPi(plhs[0]);
}
if (nlhs >= 2) {
plhs[1] = mxCreateDoubleMatrix(SRSLTE_REFSIGNAL_MAX_NUM_SF(cell.nof_prb)*nsubframes, cell.nof_ports, mxCOMPLEX);
outr1 = mxGetPr(plhs[1]);
outi1 = mxGetPi(plhs[1]);
}
if (nlhs >= 3) {
plhs[2] = mxCreateDoubleMatrix(nof_re * nsubframes, 1, mxCOMPLEX);
outr2 = mxGetPr(plhs[2]);
outi2 = mxGetPi(plhs[2]);
}
for (int sf=0;sf<nsubframes;sf++) {
/* Convert input to C complex type */
for (i=0;i<nof_re;i++) {
__real__ input_signal[i] = (float) *inr;
if (ini) {
__imag__ input_signal[i] = (float) *ini;
}
inr++;
ini++;
}
if (nsubframes != 1) {
sf_idx = sf%10;
}
if (srslte_chest_dl_estimate(&chest, input_signal, ce, sf_idx)) {
mexErrMsgTxt("Error running channel estimator\n");
return;
}
if (cell.nof_ports == 1) {
srslte_predecoding_single(input_signal, ce[0], output_signal2, nof_re, srslte_chest_dl_get_noise_estimate(&chest));
} else {
srslte_predecoding_diversity(&cheq, input_signal, ce, output_signal, cell.nof_ports, nof_re, srslte_chest_dl_get_noise_estimate(&chest));
srslte_layerdemap_diversity(output_signal, output_signal2, cell.nof_ports, nof_re/cell.nof_ports);
}
if (nlhs >= 1) {
for (int j=0;j<cell.nof_ports;j++) {
for (i=0;i<nof_re;i++) {
*outr0 = (double) crealf(ce[j][i]);
if (outi0) {
*outi0 = (double) cimagf(ce[j][i]);
}
outr0++;
outi0++;
}
}
}
if (nlhs >= 2) {
for (int j=0;j<cell.nof_ports;j++) {
for (i=0;i<SRSLTE_REFSIGNAL_NUM_SF(cell.nof_prb,j);i++) {
*outr1 = (double) crealf(chest.pilot_estimates_average[j][i]);
if (outi1) {
*outi1 = (double) cimagf(chest.pilot_estimates_average[j][i]);
}
outr1++;
outi1++;
}
}
}
if (nlhs >= 3) {
for (i=0;i<nof_re;i++) {
*outr2 = (double) crealf(output_signal2[i]);
if (outi2) {
*outi2 = (double) cimagf(output_signal2[i]);
}
outr2++;
outi2++;
}
}
}
if (nlhs >= 4) {
plhs[3] = mxCreateDoubleScalar(srslte_chest_dl_get_noise_estimate(&chest));
}
if (nlhs >= 5) {
plhs[4] = mxCreateDoubleScalar(srslte_chest_dl_get_rsrp(&chest));
}
srslte_chest_dl_free(&chest);
srslte_precoding_free(&cheq);
return;
}
