From 47cbbcbd5723c3576f987f22ec736a355ba3fe57 Mon Sep 17 00:00:00 2001 From: Xavier Arteaga Date: Wed, 4 Mar 2020 14:53:41 +0100 Subject: [PATCH] Improve PUSCH UCI decoder --- lib/include/srslte/phy/phch/uci.h | 29 +++- lib/include/srslte/phy/phch/uci_cfg.h | 1 + lib/src/phy/phch/pucch.c | 7 +- lib/src/phy/phch/sch.c | 6 +- lib/src/phy/phch/test/CMakeLists.txt | 8 +- lib/src/phy/phch/test/pusch_test.c | 10 +- lib/src/phy/phch/uci.c | 210 +++++++++++++++++--------- 7 files changed, 180 insertions(+), 91 deletions(-) diff --git a/lib/include/srslte/phy/phch/uci.h b/lib/include/srslte/phy/phch/uci.h index 8b4fa8d99..2611a4a66 100644 --- a/lib/include/srslte/phy/phch/uci.h +++ b/lib/include/srslte/phy/phch/uci.h @@ -41,6 +41,7 @@ #define SRSLTE_UCI_MAX_CQI_LEN_PUCCH 13 #define SRSLTE_UCI_CQI_CODED_PUCCH_B 20 #define SRSLTE_UCI_STR_MAX_CHAR 32 +#define SRSLTE_UCI_M_BASIS_SEQ_LEN 32 typedef struct SRSLTE_API { srslte_crc_t crc; @@ -73,10 +74,30 @@ SRSLTE_API int16_t srslte_uci_decode_cqi_pucch(srslte_uci_cqi_pucch_t* q, int16_t b_bits[SRSLTE_CQI_MAX_BITS], // aligned for simd uint8_t* cqi_data, uint32_t cqi_len); +/** + * Encodes Uplink Control Information using M-basis code block channel coding. + * + * @param input points to the bit to encode, one word per bit + * @param input_len number of bits to encode, the maximum number of bits is 11 + * @param output points to the encoded data, one word per bit + * @param output_len number of bits of encoded bits + */ +SRSLTE_API void +srslte_uci_encode_m_basis_bits(const uint8_t* input, uint32_t input_len, uint8_t* output, uint32_t output_len); -SRSLTE_API void srslte_uci_encode_ack_sr_pucch3(uint8_t* data, uint32_t nof_bits, uint8_t output[32]); - -SRSLTE_API int16_t srslte_uci_decode_ack_sr_pucch3(const int16_t llr[48], uint8_t* data); +/** + * Decodes Uplink Control Information using M-basis code block channel coding. + * + * @param llr points soft-bits + * @param nof_llr number of soft-bits, requires a minimum of 32 soft-bits + * @param data points to receice data, one word per bit + * @param data_len number of bits to decode, the maximum number of bits is 11 + * @return maximum correlation value + */ +SRSLTE_API int32_t srslte_uci_decode_m_basis_bits(const int16_t* llr, + uint32_t nof_llr, + uint8_t* data, + uint32_t data_len); SRSLTE_API int srslte_uci_cqi_init(srslte_uci_cqi_pusch_t* q); @@ -124,7 +145,7 @@ SRSLTE_API int srslte_uci_decode_ack_ri(srslte_pusch_cfg_t* cfg, uint32_t H_prime_total, uint32_t O_cqi, srslte_uci_bit_t* ack_ri_bits, - uint8_t data[2], + uint8_t data[SRSLTE_UCI_MAX_ACK_SR_BITS], uint32_t nof_bits, bool is_ri); diff --git a/lib/include/srslte/phy/phch/uci_cfg.h b/lib/include/srslte/phy/phch/uci_cfg.h index 8baa9ab77..c8cd15628 100644 --- a/lib/include/srslte/phy/phch/uci_cfg.h +++ b/lib/include/srslte/phy/phch/uci_cfg.h @@ -25,6 +25,7 @@ #include "srslte/phy/phch/cqi.h" #define SRSLTE_UCI_MAX_ACK_BITS 10 +#define SRSLTE_UCI_MAX_ACK_SR_BITS (SRSLTE_UCI_MAX_ACK_BITS + 1) #define SRSLTE_UCI_MAX_M 9 typedef struct SRSLTE_API { diff --git a/lib/src/phy/phch/pucch.c b/lib/src/phy/phch/pucch.c index 6cbc2a2f4..bb96717da 100644 --- a/lib/src/phy/phch/pucch.c +++ b/lib/src/phy/phch/pucch.c @@ -640,7 +640,7 @@ static int decode_signal_format3(srslte_pucch_t* q, srslte_scrambling_s_offset(seq, q->llr, 0, SRSLTE_PUCCH3_NOF_BITS); - return (int)srslte_uci_decode_ack_sr_pucch3(q->llr, bits); + return (int)srslte_uci_decode_m_basis_bits(q->llr, SRSLTE_PUCCH3_NOF_BITS, bits, SRSLTE_UCI_MAX_ACK_SR_BITS); } else { ERROR("Error modulating PUCCH3 bits: rnti not set\n"); return SRSLTE_ERROR; @@ -700,10 +700,7 @@ static int encode_bits(srslte_pucch_cfg_t* cfg, temp[k] = (uint8_t)(uci_data->scheduling_request ? 1 : 0); k++; } - srslte_uci_encode_ack_sr_pucch3(temp, k, pucch_bits); - for (k = 32; k < SRSLTE_PUCCH3_NOF_BITS; k++) { - pucch_bits[k] = pucch_bits[k % 32]; - } + srslte_uci_encode_m_basis_bits(temp, k, pucch_bits, SRSLTE_PUCCH3_NOF_BITS); } return SRSLTE_SUCCESS; } diff --git a/lib/src/phy/phch/sch.c b/lib/src/phy/phch/sch.c index d1c1561e0..faf5c3717 100644 --- a/lib/src/phy/phch/sch.c +++ b/lib/src/phy/phch/sch.c @@ -48,7 +48,7 @@ static inline float get_beta_harq_offset(uint32_t idx) if (idx < 15) { ret = beta_harq_offset[idx]; } else { - ERROR("Invalid inputs\n"); + ERROR("Invalid input %d (min: %d, max: %d)\n", idx, 0, 14); } return ret; @@ -64,7 +64,7 @@ static inline float get_beta_ri_offset(uint32_t idx) if (idx < 13) { ret = beta_ri_offset[idx]; } else { - ERROR("Invalid inputs\n"); + ERROR("Invalid input %d (min: %d, max: %d)\n", idx, 0, 12); } return ret; @@ -80,7 +80,7 @@ static inline float get_beta_cqi_offset(uint32_t idx) if (idx > 1 && idx < 16) { ret = beta_cqi_offset[idx]; } else { - ERROR("Invalid inputs\n"); + ERROR("Invalid input %d (min: %d, max: %d)\n", idx, 2, 15); } return ret; diff --git a/lib/src/phy/phch/test/CMakeLists.txt b/lib/src/phy/phch/test/CMakeLists.txt index d7d65e95e..fb6d1c5ea 100644 --- a/lib/src/phy/phch/test/CMakeLists.txt +++ b/lib/src/phy/phch/test/CMakeLists.txt @@ -375,7 +375,7 @@ if (TEST_EXTENSION STREQUAL Paranoid) set(pusch_max_mcs 28) set(pusch_step_mcs 1) - set(pusch_acks -1 0 1) + set(pusch_acks 0 1 2 4 5 10) set(pusch_cqi none wideband) @@ -386,7 +386,7 @@ else (TEST_EXTENSION STREQUAL Paranoid) set(pusch_max_mcs 28) set(pusch_step_mcs 10) - set(pusch_acks -1 0) + set(pusch_acks 0 1 2 10) set(pusch_cqi none wideband) @@ -409,12 +409,12 @@ foreach (cell_n_prb 6 15 25 50 75 100) set(pusch_test_args ${pusch_test_args} -n ${cell_n_prb}) set(pusch_test_args ${pusch_test_args} -L ${n_prb}) - if (NOT (${ack} EQUAL -1)) + if (NOT (${ack} EQUAL 0)) set(pusch_test_args ${pusch_test_args} -p uci_ack ${ack}) if (mcs EQUAL 28) set(mcs 27) endif (mcs EQUAL 28) - endif (NOT (${ack} EQUAL -1)) + endif (NOT (${ack} EQUAL 0)) if (NOT (${cqi} STREQUAL none)) set(pusch_test_args ${pusch_test_args} -p cqi ${cqi}) diff --git a/lib/src/phy/phch/test/pusch_test.c b/lib/src/phy/phch/test/pusch_test.c index f65354425..88d3b41fa 100644 --- a/lib/src/phy/phch/test/pusch_test.c +++ b/lib/src/phy/phch/test/pusch_test.c @@ -123,7 +123,7 @@ void parse_extensive_param(char* param, char* arg) uci_data_tx.cfg.cqi.ri_len = 1; } } else if (!strcmp(param, "uci_ack")) { - uci_data_tx.cfg.ack[0].nof_acks = SRSLTE_MIN(uci_data_tx.cfg.ack[0].nof_acks + 1, SRSLTE_UCI_MAX_ACK_BITS); + uci_data_tx.cfg.ack[0].nof_acks = SRSLTE_MIN((uint32_t)strtol(arg, NULL, 10), SRSLTE_UCI_MAX_ACK_BITS); } else if (!strcmp(param, "enable_64qam")) { enable_64_qam ^= true; } else { @@ -348,10 +348,10 @@ int main(int argc, char** argv) srslte_vec_fprint_byte(stdout, pusch_res.uci.ack.ack_value, cfg.uci_cfg.ack[0].nof_acks); ret = SRSLTE_ERROR; } else { - INFO("Rx ACK (%d bits) is Ok, %d%d\n", - uci_data_tx.cfg.ack[0].nof_acks, - uci_data_tx.value.ack.ack_value[0], - uci_data_tx.value.ack.ack_value[1]); + INFO("Rx ACK (%d bits) is Ok: ", uci_data_tx.cfg.ack[0].nof_acks); + if (srslte_verbose >= SRSLTE_VERBOSE_INFO) { + srslte_vec_fprint_byte(stdout, uci_data_tx.value.ack.ack_value, uci_data_tx.cfg.ack[0].nof_acks); + } } } diff --git a/lib/src/phy/phch/uci.c b/lib/src/phy/phch/uci.c index 43b95a38e..1a62389a6 100644 --- a/lib/src/phy/phch/uci.c +++ b/lib/src/phy/phch/uci.c @@ -39,7 +39,7 @@ #include "srslte/phy/utils/vector.h" /* Table 5.2.2.6.4-1: Basis sequence for (32, O) code */ -static uint8_t M_basis_seq[32][11] = { +static uint8_t M_basis_seq[SRSLTE_UCI_M_BASIS_SEQ_LEN][SRSLTE_UCI_MAX_ACK_SR_BITS] = { {1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1}, {1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1}, {1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1}, {1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 1}, {1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1}, {1, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1}, {1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1}, {1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1}, {1, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1}, @@ -52,13 +52,30 @@ static uint8_t M_basis_seq[32][11] = { {1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0}, {1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0}, {1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0}, {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, {1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, }; -static const uint16_t M_basis_seq_b[32] = { - 0b11000000001, 0b11100000011, 0b10010010111, 0b10110000101, 0b11110001001, 0b11001011101, 0b10101010111, - 0b10011001101, 0b11011001011, 0b10111010011, 0b10100111011, 0b11100110101, 0b10010101111, 0b11010101011, - 0b10001101001, 0b11001111011, 0b11101110010, 0b10011100100, 0b11011111000, 0b10000110000, 0b10100010001, - 0b11010000011, 0b10001001101, 0b11101000111, 0b11111011110, 0b11000111001, 0b10110100110, 0b11110101110, - 0b10101110100, 0b10111111100, 0b11111111111, 0b10000000000, -}; + +static inline bool encode_M_basis_seq_u16(uint16_t w, uint32_t bit_idx) +{ + /// Table 5.2.2.6.4-1: Basis sequence for (32, O) code compressed in uint16_t types + const uint16_t M_basis_seq_b[SRSLTE_UCI_M_BASIS_SEQ_LEN] = { + 0b10000000011, 0b11000000111, 0b11101001001, 0b10100001101, 0b10010001111, 0b10111010011, 0b11101010101, + 0b10110011001, 0b11010011011, 0b11001011101, 0b11011100101, 0b10101100111, 0b11110101001, 0b11010101011, + 0b10010110001, 0b11011110011, 0b01001110111, 0b00100111001, 0b00011111011, 0b00001100001, 0b10001000101, + 0b11000001011, 0b10110010001, 0b11100010111, 0b01111011111, 0b10011100011, 0b01100101101, 0b01110101111, + 0b00101110101, 0b00111111101, 0b11111111111, 0b00000000001, + }; + + // Apply mask + uint16_t d = (uint16_t)w & M_basis_seq_b[bit_idx % SRSLTE_UCI_M_BASIS_SEQ_LEN]; + + // Compute parity + d ^= (uint16_t)(d >> 8U); + d ^= (uint16_t)(d >> 4U); + d &= 0xf; + d = (0x6996U >> d) & 1U; + + // Return false if 0, otherwise it returns true + return (d != 0); +} static uint8_t M_basis_seq_pucch[20][13] = { {1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0}, {1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0}, @@ -174,50 +191,85 @@ int16_t srslte_uci_decode_cqi_pucch(srslte_uci_cqi_pucch_t* q, } } -void encode_cqi_pusch_block(const uint8_t* data, uint32_t nof_bits, uint8_t output[32]) +void srslte_uci_encode_m_basis_bits(const uint8_t* input, uint32_t input_len, uint8_t* output, uint32_t output_len) { - for (int i = 0; i < 32; i++) { - output[i] = 0; - for (int n = 0; n < nof_bits; n++) { - output[i] = (output[i] + data[n] * M_basis_seq[i][n]) % 2; - } + // Limit number of input bits + input_len = SRSLTE_MIN(input_len, SRSLTE_UCI_MAX_ACK_SR_BITS); + + // Pack input bits + uint16_t w = 0; + for (uint32_t i = 0; i < input_len; i++) { + w |= (input[i] & 1U) << i; } -} -void srslte_uci_encode_ack_sr_pucch3(uint8_t* data, uint32_t nof_bits, uint8_t output[32]) -{ - encode_cqi_pusch_block(data, nof_bits, output); + // Encode bits + for (uint32_t i = 0; i < SRSLTE_MIN(output_len, SRSLTE_UCI_M_BASIS_SEQ_LEN); i++) { + output[i] = encode_M_basis_seq_u16(w, i); + } + + // Avoid repeating operation by copying repeated sequence + for (uint32_t i = SRSLTE_UCI_M_BASIS_SEQ_LEN; i < output_len; i++) { + output[i] = output[i % SRSLTE_UCI_M_BASIS_SEQ_LEN]; + } } -int16_t srslte_uci_decode_ack_sr_pucch3(const int16_t llr[48], uint8_t* data) +int32_t srslte_uci_decode_m_basis_bits(const int16_t* llr, uint32_t nof_llr, uint8_t* data, uint32_t data_len) { - int16_t max_corr = 0; - int16_t max_data = 0; + int32_t max_corr = 0; ///< Stores maximum correlation + uint16_t max_data = 0; ///< Stores the word for maximum correlation + + // Return invalid inputs if data is not provided + if (!llr || !data) { + ERROR("Invalid inputs\n"); + return SRSLTE_ERROR_INVALID_INPUTS; + } + + // Return invalid inputs if not enough LLR are provided + if (nof_llr < SRSLTE_UCI_M_BASIS_SEQ_LEN) { + ERROR("Not enough LLR bits are provided %d. Required %d;\n", nof_llr, SRSLTE_UCI_M_BASIS_SEQ_LEN); + return SRSLTE_ERROR_INVALID_INPUTS; + } + + // Limit data to maximum + data_len = SRSLTE_MIN(data_len, SRSLTE_UCI_MAX_ACK_SR_BITS); + + // Brute force all possible sequences + uint16_t max_guess = (1 << data_len); ///< Maximum guess bit combination + for (uint16_t guess = 0; guess < max_guess; guess++) { + int32_t corr = 0; + + /// Compute correlation for the number of LLR + bool early_termination = false; + for (uint8_t i = 0; i < nof_llr && !early_termination; i++) { + // Encode guess word + bool d = encode_M_basis_seq_u16(guess, i); - // Brute force all sequences backwards - for (int16_t guess = 2047; guess >= 0; guess--) { - int16_t corr = 0; + // Correlate + corr += (int32_t)(d ? llr[i] : -llr[i]); - for (uint8_t i = 0; i < 48; i++) { - uint16_t d = (uint16_t)guess & M_basis_seq_b[i % 32]; - d ^= (uint16_t)(d >> 8U); - d ^= (uint16_t)(d >> 4U); - d &= 0xf; - d = (0x6996U >> d) & 1U; + // Limit correlation to half range + corr = SRSLTE_MIN(corr, INT32_MAX / 2); - corr += (d ? 1 : -1) * llr[i]; + /// Early terminates if at least SRSLTE_UCI_M_BASIS_SEQ_LEN/4 LLR processed and negative correlation + early_termination |= (i > SRSLTE_UCI_M_BASIS_SEQ_LEN / 4) && (corr < 0); + + /// Early terminates if the correlation overflows + early_termination |= (corr < -INT32_MAX / 2); } + // Take decision if (corr > max_corr) { max_corr = corr; max_data = guess; } } - for (int8_t i = 0; i < 11; i++) { - data[i] = (uint8_t)(max_data >> (10U - i)) & 1U; + // Unpack + for (uint32_t i = 0; i < data_len; i++) { + data[i] = (uint8_t)(max_data >> i) & 1U; } + // Return correlation return max_corr; } @@ -232,7 +284,7 @@ void cqi_pusch_pregen(srslte_uci_cqi_pusch_t* q) for (uint32_t w = 0; w < nwords; w++) { uint8_t* ptr = word; srslte_bit_unpack(w, &ptr, i + 1); - encode_cqi_pusch_block(word, i + 1, &q->cqi_table[i][32 * w]); + srslte_uci_encode_m_basis_bits(word, i + 1, &q->cqi_table[i][32 * w], SRSLTE_UCI_M_BASIS_SEQ_LEN); for (int j = 0; j < 32; j++) { q->cqi_table_s[i][32 * w + j] = 2 * q->cqi_table[i][32 * w + j] - 1; } @@ -604,8 +656,8 @@ encode_ack_long(uint8_t* data, uint32_t O_ack, uint8_t Q_m, uint32_t Q_prime, sr { uint32_t Q_ack = Q_m * Q_prime; - if (O_ack > 10) { - ERROR("Error encoding long ACK bits: O_ack can't be higher than 10\n"); + if (O_ack > SRSLTE_UCI_MAX_ACK_BITS) { + ERROR("Error encoding long ACK bits: O_ack can't be higher than %d\n", SRSLTE_UCI_MAX_ACK_BITS); return 0; } @@ -620,35 +672,34 @@ encode_ack_long(uint8_t* data, uint32_t O_ack, uint8_t Q_m, uint32_t Q_prime, sr return Q_ack; } -/* Decode UCI HARQ/ACK bits as described in 5.2.2.6 of 36.212 - */ -static int32_t decode_ri_ack_1bit(int16_t* q_bits, uint8_t* c_seq, srslte_uci_bit_t* pos) +static void decode_ri_ack_1bit(const int16_t* q_bits, const uint8_t* c_seq, uint8_t data[1]) { - uint32_t p0 = pos[0].position; - uint32_t p1 = pos[1].position; - // Unscramble p1 - q_bits[p1] = c_seq[p1] ? -q_bits[p1] : q_bits[p1]; + int16_t q1 = c_seq[1] ? -q_bits[1] : q_bits[1]; // Scramble with correct position - int16_t q0 = q_bits[p0]; - int16_t q1 = c_seq[p0] ? -q_bits[p1] : q_bits[p1]; + int16_t q0 = q_bits[0]; + q1 = c_seq[0] ? -q1 : q1; - return (q0 + q1); + if (data) { + data[0] = ((q0 + q1) > 0) ? 1 : 0; + } } -static void decode_ri_ack_2bits(int16_t* q_bits, uint8_t* c_seq, srslte_uci_bit_t* pos, uint32_t Qm, int32_t data[3]) +static bool decode_ri_ack_2bits(const int16_t* llr, uint32_t Qm, uint8_t data[2]) { - uint32_t p0 = pos[Qm * 0 + 0].position; - uint32_t p1 = pos[Qm * 0 + 1].position; - uint32_t p2 = pos[Qm * 1 + 0].position; - uint32_t p3 = pos[Qm * 1 + 1].position; - uint32_t p4 = pos[Qm * 2 + 0].position; - uint32_t p5 = pos[Qm * 2 + 1].position; + uint32_t p0 = Qm * 0 + 0; + uint32_t p1 = Qm * 0 + 1; + uint32_t p2 = Qm * 1 + 0; + uint32_t p3 = Qm * 1 + 1; + uint32_t p4 = Qm * 2 + 0; + uint32_t p5 = Qm * 2 + 1; - data[0] += q_bits[p0] + q_bits[p3]; - data[1] += q_bits[p1] + q_bits[p4]; - data[2] += q_bits[p2] + q_bits[p5]; + data[0] = ((llr[p0] + llr[p3]) > 0) ? 1 : 0; + data[1] = ((llr[p1] + llr[p4]) > 0) ? 1 : 0; + + // Return parity check + return ((llr[p2] + llr[p5]) > 0) == ((data[0] ^ data[1]) == 1); } // Table 5.2.2.6-A @@ -750,36 +801,55 @@ int srslte_uci_decode_ack_ri(srslte_pusch_cfg_t* cfg, uint32_t H_prime_total, uint32_t O_cqi, srslte_uci_bit_t* ack_ri_bits, - uint8_t data[2], + uint8_t data[SRSLTE_UCI_MAX_ACK_SR_BITS], uint32_t nof_bits, bool is_ri) { - int32_t sum[3] = {0, 0, 0}; - if (beta < 0) { - ERROR("Error beta is reserved\n"); - return -1; + ERROR("Error beta (%f) is reserved\n", beta); + return SRSLTE_ERROR; } uint32_t Qprime = Q_prime_ri_ack(cfg, nof_bits, O_cqi, beta); uint32_t Qm = srslte_mod_bits_x_symbol(cfg->grant.tb.mod); + int16_t llr_acc[32] = {}; ///< LLR accumulator + uint32_t nof_acc = + (nof_bits == 1) ? Qm : (nof_bits == 2) ? Qm * 3 : SRSLTE_UCI_M_BASIS_SEQ_LEN; ///< Number of required LLR + uint32_t count_acc = 0; ///< LLR counter + for (uint32_t i = 0; i < Qprime; i++) { if (is_ri) { - uci_ulsch_interleave_ri_gen(i, Qm, H_prime_total, cfg->grant.nof_symb, &ack_ri_bits[Qm * i]); + uci_ulsch_interleave_ri_gen(i, Qm, H_prime_total, cfg->grant.nof_symb, &ack_ri_bits[count_acc]); } else { - uci_ulsch_interleave_ack_gen(i, Qm, H_prime_total, cfg->grant.nof_symb, &ack_ri_bits[Qm * i]); + uci_ulsch_interleave_ack_gen(i, Qm, H_prime_total, cfg->grant.nof_symb, &ack_ri_bits[count_acc]); } - if (nof_bits == 2 && (i % 3 == 0) && i > 0) { - decode_ri_ack_2bits(q_bits, &c_seq[0], &ack_ri_bits[Qm * (i - 3)], Qm, sum); - } else if (nof_bits == 1) { - sum[0] += (int32_t)decode_ri_ack_1bit(q_bits, c_seq, &ack_ri_bits[Qm * i]); + + /// Extract and accumulate LLR + for (uint32_t j = 0; j < Qm; j++, count_acc++) { + // Calculate circular LLR index + uint32_t acc_idx = count_acc % nof_acc; + + // Accumulate LLR + llr_acc[acc_idx] += q_bits[ack_ri_bits[count_acc].position]; + + /// Limit accumulator boundaries + llr_acc[acc_idx] = SRSLTE_MIN(llr_acc[acc_idx], INT16_MAX / 2); + llr_acc[acc_idx] = SRSLTE_MAX(llr_acc[acc_idx], -INT16_MAX / 2); } } - data[0] = (uint8_t)(sum[0] > 0); - if (nof_bits == 2) { - data[1] = (uint8_t)(sum[1] > 0); + /// Decode UCI HARQ/ACK bits as described in 5.2.2.6 of 36.212 + switch (nof_bits) { + case 1: + decode_ri_ack_1bit(llr_acc, c_seq, data); + break; + case 2: + decode_ri_ack_2bits(llr_acc, Qm, data); + break; + default: + // For more than 2 bits... + srslte_uci_decode_m_basis_bits(llr_acc, SRSLTE_UCI_M_BASIS_SEQ_LEN, data, nof_bits); } return (int)Qprime;