215 lines
6.2 KiB
C
215 lines
6.2 KiB
C
/**
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*
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* \section COPYRIGHT
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*
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* Copyright 2013-2014 The libLTE Developers. See the
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* COPYRIGHT file at the top-level directory of this distribution.
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*
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* \section LICENSE
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*
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* This file is part of the libLTE library.
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*
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* libLTE is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation, either version 3 of
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* the License, or (at your option) any later version.
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*
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* libLTE 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 Lesser General Public License for more details.
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*
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* A copy of the GNU Lesser General Public License can be found in
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* the LICENSE file in the top-level directory of this distribution
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* and at http://www.gnu.org/licenses/.
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*
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*/
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#include <stdio.h>
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#include <assert.h>
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#include <string.h>
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#include "lte/common/base.h"
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#include "lte/mimo/layermap.h"
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int layermap_single(cf_t *d, cf_t *x, int nof_symbols) {
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memcpy(x, d, sizeof(cf_t) * nof_symbols);
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return nof_symbols;
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}
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int layermap_diversity(cf_t *d, cf_t *x[MAX_LAYERS], int nof_layers, int nof_symbols) {
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int i, j;
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for (i=0;i<nof_symbols/nof_layers;i++) {
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for (j=0;j<nof_layers;j++) {
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x[j][i] = d[nof_layers*i+j];
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}
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}
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return i;
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}
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int layermap_multiplex(cf_t *d[MAX_CODEWORDS], cf_t *x[MAX_LAYERS], int nof_cw, int nof_layers,
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int nof_symbols[MAX_CODEWORDS]) {
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if (nof_cw == 1) {
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return layermap_diversity(d[0], x, nof_layers, nof_symbols[0]);
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} else {
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int n[2];
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n[0] = nof_layers / nof_cw;
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n[1] = nof_layers - n[0];
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if (nof_symbols[0] / n[0] == nof_symbols[1] / n[1]) {
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layermap_diversity(d[0], x, n[0], nof_symbols[0]);
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layermap_diversity(d[1], &x[n[0]], n[1], nof_symbols[1]);
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return nof_symbols[0] / n[0];
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} else {
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fprintf(stderr, "Number of symbols in codewords 0 and 1 is not consistent (%d, %d)\n",
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nof_symbols[0], nof_symbols[1]);
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return -1;
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}
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}
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return 0;
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}
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/* Layer mapping generates the vector of layer-mapped symbols "x" based on the vector of data symbols "d"
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* Based on 36.211 6.3.3
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* Returns the number of symbols per layer (M_symb^layer in the specs)
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*/
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int layermap_type(cf_t *d[MAX_CODEWORDS], cf_t *x[MAX_LAYERS], int nof_cw, int nof_layers,
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int nof_symbols[MAX_CODEWORDS], mimo_type_t type) {
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if (nof_cw > MAX_CODEWORDS) {
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fprintf(stderr, "Maximum number of codewords is %d (nof_cw=%d)\n", MAX_CODEWORDS, nof_cw);
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return -1;
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}
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if (nof_layers > MAX_LAYERS) {
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fprintf(stderr, "Maximum number of layers is %d (nof_layers=%d)\n", MAX_LAYERS, nof_layers);
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return -1;
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}
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if (nof_layers < nof_cw) {
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fprintf(stderr, "Number of codewords must be lower or equal than number of layers\n");
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return -1;
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}
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switch(type) {
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case SINGLE_ANTENNA:
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if (nof_cw == 1 && nof_layers == 1) {
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return layermap_single(x[0], d[0], nof_symbols[0]);
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} else {
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fprintf(stderr, "Number of codewords and layers must be 1 for transmission on single antenna ports\n");
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return -1;
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}
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break;
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case TX_DIVERSITY:
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if (nof_cw == 1) {
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if (nof_layers == 2 || nof_layers == 4) {
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return layermap_diversity(d[0], x, nof_layers, nof_symbols[0]);
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} else {
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fprintf(stderr, "Number of layers must be 2 or 4 for transmit diversity\n");
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return -1;
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}
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} else {
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fprintf(stderr, "Number of codewords must be 1 for transmit diversity\n");
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return -1;
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}
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break;
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case SPATIAL_MULTIPLEX:
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return layermap_multiplex(d, x, nof_cw, nof_layers, nof_symbols);
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break;
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}
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return 0;
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}
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int layerdemap_single(cf_t *x, cf_t *d, int nof_symbols) {
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memcpy(d, x, sizeof(cf_t) * nof_symbols);
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return nof_symbols;
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}
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int layerdemap_diversity(cf_t *x[MAX_LAYERS], cf_t *d, int nof_layers, int nof_layer_symbols) {
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int i, j;
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for (i=0;i<nof_layer_symbols;i++) {
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for (j=0;j<nof_layers;j++) {
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d[nof_layers*i+j] = x[j][i];
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}
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}
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return nof_layer_symbols * nof_layers;
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}
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int layerdemap_multiplex(cf_t *x[MAX_LAYERS], cf_t *d[MAX_CODEWORDS], int nof_layers, int nof_cw,
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int nof_layer_symbols, int nof_symbols[MAX_CODEWORDS]) {
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if (nof_cw == 1) {
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return layerdemap_diversity(x, d[0], nof_layers, nof_layer_symbols);
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} else {
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int n[2];
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n[0] = nof_layers / nof_cw;
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n[1] = nof_layers - n[0];
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nof_symbols[0] = n[0] * nof_layer_symbols;
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nof_symbols[1] = n[1] * nof_layer_symbols;
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nof_symbols[0] = layerdemap_diversity(x, d[0], n[0], nof_layer_symbols);
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nof_symbols[1] = layerdemap_diversity(&x[n[0]], d[1], n[1], nof_layer_symbols);
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}
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return 0;
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}
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/* Generates the vector of data symbols "d" based on the vector of layer-mapped symbols "x"
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* Based on 36.211 6.3.3
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* Returns 0 on ok and saves the number of symbols per codeword (M_symb^(q) in the specs) in
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* nof_symbols. Returns -1 on error
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*/
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int layerdemap_type(cf_t *x[MAX_LAYERS], cf_t *d[MAX_CODEWORDS], int nof_layers, int nof_cw,
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int nof_layer_symbols, int nof_symbols[MAX_CODEWORDS], mimo_type_t type) {
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if (nof_cw > MAX_CODEWORDS) {
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fprintf(stderr, "Maximum number of codewords is %d (nof_cw=%d)\n", MAX_CODEWORDS, nof_cw);
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return -1;
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}
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if (nof_layers > MAX_LAYERS) {
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fprintf(stderr, "Maximum number of layers is %d (nof_layers=%d)\n", MAX_LAYERS, nof_layers);
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return -1;
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}
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if (nof_layers < nof_cw) {
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fprintf(stderr, "Number of codewords must be lower or equal than number of layers\n");
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return -1;
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}
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switch(type) {
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case SINGLE_ANTENNA:
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if (nof_cw == 1 && nof_layers == 1) {
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nof_symbols[0] = layerdemap_single(x[0], d[0], nof_layer_symbols);
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nof_symbols[1] = 0;
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} else {
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fprintf(stderr, "Number of codewords and layers must be 1 for transmission on single antenna ports\n");
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return -1;
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}
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break;
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case TX_DIVERSITY:
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if (nof_cw == 1) {
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if (nof_layers == 2 || nof_layers == 4) {
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nof_symbols[0] = layerdemap_diversity(x, d[0], nof_layers, nof_layer_symbols);
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nof_symbols[1] = 0;
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} else {
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fprintf(stderr, "Number of layers must be 2 or 4 for transmit diversity\n");
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return -1;
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}
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} else {
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fprintf(stderr, "Number of codewords must be 1 for transmit diversity\n");
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return -1;
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}
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break;
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case SPATIAL_MULTIPLEX:
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return layerdemap_multiplex(x, d, nof_layers, nof_cw, nof_layer_symbols, nof_symbols);
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break;
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}
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return 0;
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}
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