int dci_format1Cs_unpack(dci_msg_t *msg, ra_pdsch_t *data, int nof_prb) {
uint16_t L_p, RB_p;
/* pack bits */
char *y = msg->data;
if (msg->location.nof_bits != dci_format_sizeof(Format1C, nof_prb)) {
fprintf(stderr, "Invalid message length for format 1C\n");
return -1;
}
data->alloc_type = alloc_type2;
data->type2_alloc.mode = t2_dist;
if (nof_prb >= 50) {
data->type2_alloc.n_gap = *y++;
}
int n_step = ra_type2_n_rb_step(nof_prb);
int n_vrb_dl = ra_type2_n_vrb_dl(nof_prb, data->type2_alloc.n_gap == t2_ng1);
uint32_t riv = bit_unpack(&y, riv_nbits((int) n_vrb_dl / n_step));
int n_vrb_p = (int) n_vrb_dl / n_step;
ra_type2_from_riv(riv, &L_p, &RB_p, n_vrb_p, n_vrb_p);
data->type2_alloc.L_crb = L_p * n_step;
data->type2_alloc.RB_start = RB_p * n_step;
data->type2_alloc.riv = riv;
data->mcs.mcs_idx = bit_unpack(&y, 5);
data->mcs.tbs_idx = data->mcs.mcs_idx;
data->mcs.tbs = ra_tbs_from_idx_format1c(data->mcs.tbs_idx);
data->mcs.mod = QPSK;
msg->location.nof_bits = (y - msg->data);
return 0;
}
int mod_modulate(modem_table_t* q, const uint8_t *bits, cf* symbols, int nbits) {
int i,j,idx;
uint8_t *b_ptr=(uint8_t*) bits;
j=0;
for (i=0;i<nbits;i+=q->nbits_x_symbol) {
idx = bit_unpack(&b_ptr,q->nbits_x_symbol);
symbols[j] = q->symbol_table[idx];
j++;
}
return j;
}
/** Unpacks MIB from PBCH message.
* msg buffer must be 24 byte length at least
*/
void pbch_mib_unpack(char *msg, pbch_mib_t *mib) {
int bw, phich_res;
bw = bit_unpack(&msg, 3);
switch (bw) {
case 0:
mib->nof_prb = 6;
break;
case 1:
mib->nof_prb = 15;
break;
default:
mib->nof_prb = (bw - 1) * 25;
break;
}
if (*msg) {
mib->phich_length = PHICH_EXT;
} else {
mib->phich_length = PHICH_NORM;
}
msg++;
phich_res = bit_unpack(&msg, 2);
switch (phich_res) {
case 0:
mib->phich_resources = R_1_6;
break;
case 1:
mib->phich_resources = R_1_2;
break;
case 2:
mib->phich_resources = R_1;
break;
case 3:
mib->phich_resources = R_2;
break;
}
mib->sfn = bit_unpack(&msg, 8) << 2;
}
int dci_format1_unpack(dci_msg_t *msg, ra_pdsch_t *data, int nof_prb) {
/* pack bits */
char *y = msg->data;
/* Make sure it's a Format1 message */
if (msg->location.nof_bits != dci_format_sizeof(Format1, nof_prb)) {
fprintf(stderr, "Invalid message length for format 1\n");
return -1;
}
if (nof_prb > 10) {
data->alloc_type = *y++;
} else {
data->alloc_type = alloc_type0;
}
/* Resource allocation: type0 or type 1 */
int P = ra_type0_P(nof_prb);
int alloc_size = (int) ceilf((float) nof_prb / P);
switch (data->alloc_type) {
case alloc_type0:
data->type0_alloc.rbg_bitmask = bit_unpack(&y, alloc_size);
break;
case alloc_type1:
data->type1_alloc.rbg_subset = bit_unpack(&y, (int) ceilf(log2f(P)));
data->type1_alloc.shift = *y++ ? true : false;
data->type1_alloc.vrb_bitmask = bit_unpack(&y,
alloc_size - (int) ceilf(log2f(P)) - 1);
break;
default:
fprintf(stderr,
"Format 1 accepts type0 or type1 resource allocation only\n");
return -1;
}
/* pack MCS according to 7.1.7 of 36.213 */
uint32_t mcs = bit_unpack(&y, 5);
data->mcs.mcs_idx = mcs;
ra_mcs_from_idx_dl(mcs, &data->mcs);
data->mcs.tbs = ra_tbs_from_idx(data->mcs.tbs_idx, ra_nprb_dl(data, nof_prb));
/* harq process number */
data->harq_process = bit_unpack(&y, 3);
data->ndi = *y++ ? true : false;
// rv version
data->rv_idx = bit_unpack(&y, 2);
// TPC not implemented
return 0;
}
/* Unpacks DCI format 1A for compact scheduling of PDSCH words according to 36.212 5.3.3.1.3
*
*/
int dci_format1As_unpack(dci_msg_t *msg, ra_pdsch_t *data, int nof_prb,
bool crc_is_crnti) {
/* pack bits */
char *y = msg->data;
/* Make sure it's a Format0 message */
if (msg->location.nof_bits != dci_format_sizeof(Format1A, nof_prb)) {
fprintf(stderr, "Invalid message length for format 1A\n");
return -1;
}
if (*y++ != 1) {
fprintf(stderr,
"Invalid format differentiation field value. This is Format0\n");
return -1;
}
data->alloc_type = alloc_type2;
data->type2_alloc.mode = *y++;
// by default, set N_gap to 1
data->type2_alloc.n_gap = t2_ng1;
/* unpack RIV according to 7.1.6.3 of 36.213 */
int nb_gap = 0;
if (crc_is_crnti && data->type2_alloc.mode == t2_dist && nof_prb >= 50) {
nb_gap = 1;
data->type2_alloc.n_gap = *y++;
}
int nof_vrb;
if (data->type2_alloc.mode == t2_loc) {
nof_vrb = nof_prb;
} else {
nof_vrb = ra_type2_n_vrb_dl(nof_prb, data->type2_alloc.n_gap == t2_ng1);
}
uint32_t riv = bit_unpack(&y, riv_nbits(nof_prb) - nb_gap);
ra_type2_from_riv(riv, &data->type2_alloc.L_crb, &data->type2_alloc.RB_start,
nof_prb, nof_vrb);
data->type2_alloc.riv = riv;
// unpack MCS
data->mcs.mcs_idx = bit_unpack(&y, 5);
data->harq_process = bit_unpack(&y, 3);
if (!crc_is_crnti && nof_prb >= 50 && data->type2_alloc.mode == t2_dist) {
data->type2_alloc.n_gap = *y++;
} else {
y++; // bit reserved
}
// rv version
bit_pack(data->rv_idx, &y, 2);
if (crc_is_crnti) {
// TPC not implemented
y++;
y++;
} else {
y++; // MSB of TPC is reserved
data->type2_alloc.n_prb1a = *y++; // LSB indicates N_prb_1a for TBS
}
data->mcs.tbs_idx = data->mcs.mcs_idx;
int n_prb;
if (crc_is_crnti) {
n_prb = ra_nprb_dl(data, nof_prb);
} else {
n_prb = data->type2_alloc.n_prb1a == nprb1a_2 ? 2 : 3;
}
data->mcs.tbs = ra_tbs_from_idx(data->mcs.tbs_idx, n_prb);
data->mcs.mod = QPSK;
return 0;
}
/* Unpacks DCI format 0 data and store result in msg according
* to 36.212 5.3.3.1.1
*
* TODO: TPC and cyclic shift for DM RS not implemented
*/
int dci_format0_unpack(dci_msg_t *msg, ra_pusch_t *data, int nof_prb) {
/* pack bits */
char *y = msg->data;
int n_ul_hop;
/* Make sure it's a Format0 message */
if (msg->location.nof_bits != dci_format_sizeof(Format0, nof_prb)) {
fprintf(stderr, "Invalid message length for format 0\n");
return -1;
}
if (*y++ != 0) {
fprintf(stderr,
"Invalid format differentiation field value. This is Format1A\n");
return -1;
}
if (*y++ == 0) {
data->freq_hop_fl = hop_disabled;
n_ul_hop = 0;
} else {
if (nof_prb < 50) {
n_ul_hop = 1; // Table 8.4-1 of 36.213
data->freq_hop_fl = *y++;
} else {
n_ul_hop = 2; // Table 8.4-1 of 36.213
data->freq_hop_fl = y[0] << 1 | y[1];
y += 2;
}
}
/* unpack RIV according to 8.1 of 36.213 */
uint32_t riv = bit_unpack(&y, riv_nbits(nof_prb) - n_ul_hop);
ra_type2_from_riv(riv, &data->type2_alloc.L_crb, &data->type2_alloc.RB_start,
nof_prb, nof_prb);
bit_pack(riv, &y, riv_nbits(nof_prb) - n_ul_hop);
data->type2_alloc.riv = riv;
/* unpack MCS according to 8.6 of 36.213 */
uint32_t mcs = bit_unpack(&y, 5);
data->ndi = *y++ ? true : false;
// TCP and DM RS commands not implemented
y += 5;
// CQI request
data->cqi_request = *y++ ? true : false;
// 8.6.2 First paragraph
if (mcs <= 28) {
ra_mcs_from_idx_ul(mcs, &data->mcs);
data->mcs.tbs = ra_tbs_from_idx(data->mcs.tbs_idx,
ra_nprb_ul(data, nof_prb));
}
// 8.6.1 and 8.6.2 36.213 second paragraph
if (mcs == 29 && data->cqi_request && ra_nprb_ul(data, nof_prb) <= 4) {
data->mcs.mod = QPSK;
}
if (mcs > 29) {
// Else leave MOD_NULL and use the previously used PUSCH modulation
data->mcs.mod = MOD_NULL;
data->rv_idx = mcs - 28;
}
return 0;
}
