From 08799cfe0fb625c41655a1f83bfa829d15d4bbc0 Mon Sep 17 00:00:00 2001 From: Xavier Arteaga Date: Wed, 2 Dec 2020 17:46:42 +0100 Subject: [PATCH] NR CSI-RS initial put/measure --- lib/src/phy/ch_estimation/csi_rs.c | 301 ++++++++++++++++++++++------- 1 file changed, 230 insertions(+), 71 deletions(-) diff --git a/lib/src/phy/ch_estimation/csi_rs.c b/lib/src/phy/ch_estimation/csi_rs.c index e538c0981..e52215e9e 100644 --- a/lib/src/phy/ch_estimation/csi_rs.c +++ b/lib/src/phy/ch_estimation/csi_rs.c @@ -10,9 +10,10 @@ * */ -#include "srslte/config.h" -#include "srslte/phy/common/phy_common_nr.h" -#include "srslte/phy/utils/debug.h" +#include "srslte/phy/ch_estimation/csi_rs.h" +#include "srslte/phy/common/sequence.h" +#include "srslte/phy/utils/vector.h" +#include #include #include @@ -22,73 +23,6 @@ #define SRSLTE_CSI_RS_NOF_FREQ_DOMAIN_ALLOC_OTHER 6 #define SRSLTE_CSI_RS_NOF_FREQ_DOMAIN_ALLOC_MAX 12 -typedef enum SRSLTE_API { - srslte_csi_rs_resource_mapping_row_1 = 0, - srslte_csi_rs_resource_mapping_row_2, - srslte_csi_rs_resource_mapping_row_4, - srslte_csi_rs_resource_mapping_row_other, -} srslte_csi_rs_resource_mapping_row_t; - -typedef enum SRSLTE_API { - srslte_csi_rs_resource_mapping_density_three = 0, - srslte_csi_rs_resource_mapping_density_dot5_even, - srslte_csi_rs_resource_mapping_density_dot5_odd, - srslte_csi_rs_resource_mapping_density_one, - srslte_csi_rs_resource_mapping_density_spare -} srslte_csi_rs_density_t; - -typedef enum SRSLTE_API { - srslte_csi_rs_cdm_nocdm = 0, - srslte_csi_rs_cdm_fd_cdm2, - srslte_csi_rs_cdm_cdm4_fd2_td2, - srslte_csi_rs_cdm_cdm8_fd2_td4 -} srslte_csi_rs_cdm_t; - -/** - * @brief Contains CSI-FrequencyOccupation flattened configuration - */ -typedef struct SRSLTE_API { - uint32_t start_rb; // 0..274 - uint32_t nof_rb; // 24..276 -} srslte_csi_rs_freq_occupation_t; - -/** - * @brief Contains CSI-ResourcePeriodicityAndOffset flattened configuration - */ -typedef struct SRSLTE_API { - uint32_t period; // 4,5,8,10,16,20,32,40,64,80,160,320,640 - uint32_t offset; // 0..period-1 -} srslte_csi_rs_period_and_offset_t; - -/** - * @brief Contains CSI-RS-ResourceMapping flattened configuration - */ -typedef struct SRSLTE_API { - srslte_csi_rs_resource_mapping_row_t row; - bool frequency_domain_alloc[SRSLTE_CSI_RS_NOF_FREQ_DOMAIN_ALLOC_MAX]; - uint32_t ports; // 1, 2, 4, 8, 12, 16, 24, 32 - uint32_t first_symbol_idx; // 0..13 - uint32_t first_symbol_idx2; // 2..12 (set to 0 for disabled) - srslte_csi_rs_cdm_t cdm; - srslte_csi_rs_density_t density; - srslte_csi_rs_freq_occupation_t freq_band; -} srslte_csi_rs_resource_mapping_t; - -/** - * @brief Contains NZP-CSI-RS-Resource flattened configuration - */ -typedef struct SRSLTE_API { - srslte_csi_rs_resource_mapping_t resource_mapping; - - int8_t power_control_offset; // -8..15 dB - int8_t power_control_offset_ss; // -3, 0, 3, 6 dB - - uint32_t scrambling_id; // 0..1023 - - srslte_csi_rs_period_and_offset_t periodicity; - -} srslte_csi_rs_nzp_resource_t; - #define CSI_RS_MAX_CDM_GROUP 16 static int csi_rs_location_f(const srslte_csi_rs_resource_mapping_t* resource, uint32_t i) @@ -123,6 +57,7 @@ static int csi_rs_location_f(const srslte_csi_rs_resource_mapping_t* resource, u return SRSLTE_ERROR; } +// Table 7.4.1.5.3-1: CSI-RS locations within a slot static int csi_rs_location_get_k_list(const srslte_csi_rs_resource_mapping_t* resource, uint32_t k_list[CSI_RS_MAX_CDM_GROUP]) { @@ -147,6 +82,7 @@ static int csi_rs_location_get_k_list(const srslte_csi_rs_resource_mapping_t* re return SRSLTE_ERROR; } +// Table 7.4.1.5.3-1: CSI-RS locations within a slot static int csi_rs_location_get_l_list(const srslte_csi_rs_resource_mapping_t* resource, uint32_t l_list[CSI_RS_MAX_CDM_GROUP]) { @@ -171,7 +107,230 @@ static int csi_rs_location_get_l_list(const srslte_csi_rs_resource_mapping_t* re return SRSLTE_ERROR; } -int srslte_csi_rs_put(const srslte_carrier_nr_t* carrier) +uint32_t csi_rs_cinit(const srslte_carrier_nr_t* carrier, + const srslte_dl_slot_cfg_t* slot_cfg, + const srslte_csi_rs_nzp_resource_t* resource, + uint32_t l) +{ + uint32_t n = slot_cfg->idx % SRSLTE_NSLOTS_PER_FRAME_NR(carrier->numerology); + uint32_t n_id = resource->scrambling_id; + + return ((SRSLTE_NSYMB_PER_SLOT_NR * n + l + 1UL) * (2UL * n_id) << 10UL) + n_id; +} + +bool srslte_csi_send(const srslte_csi_rs_period_and_offset_t* periodicity, const srslte_dl_slot_cfg_t* slot_cfg) +{ + if (periodicity == NULL || slot_cfg == NULL) { + return false; + } + + if (periodicity->period == 0) { + return false; + } + + uint32_t n = ((slot_cfg->idx + periodicity->period) - periodicity->offset) % periodicity->period; + + return n == 0; +} + +uint32_t csi_rs_count(srslte_csi_rs_density_t density, uint32_t nprb) { + switch (density) { + + case srslte_csi_rs_resource_mapping_density_three: + return nprb * 3; + case srslte_csi_rs_resource_mapping_density_dot5_even: + return nprb / 2; + case srslte_csi_rs_resource_mapping_density_dot5_odd: + return nprb / 2; + case srslte_csi_rs_resource_mapping_density_one: + return nprb; + case srslte_csi_rs_resource_mapping_density_spare: + default:; // Do nothing + } + return 0; +} + +int srslte_csi_rs_nzp_put(const srslte_carrier_nr_t* carrier, + const srslte_dl_slot_cfg_t* slot_cfg, + const srslte_csi_rs_nzp_resource_t* resource, + cf_t* grid) +{ + if (carrier == NULL || resource == NULL || grid == NULL) { + return SRSLTE_ERROR; + } + + uint32_t k_list[CSI_RS_MAX_CDM_GROUP]; + int nof_k = csi_rs_location_get_k_list(&resource->resource_mapping, k_list); + if (nof_k <= 0) { + return SRSLTE_ERROR; + } + + uint32_t l_list[CSI_RS_MAX_CDM_GROUP]; + int nof_l = csi_rs_location_get_l_list(&resource->resource_mapping, l_list); + if (nof_l <= 0) { + return SRSLTE_ERROR; + } + + // Calculate Resource Block boundaries + uint32_t rb_begin = resource->resource_mapping.freq_band.start_rb; + uint32_t rb_end = resource->resource_mapping.freq_band.start_rb + resource->resource_mapping.freq_band.nof_rb; + uint32_t rb_stride = 1; + + // Calculate power allocation + float beta = srslte_convert_dB_to_amplitude((float)resource->power_control_offset); + if (!isnormal(beta)) { + beta = 1.0f; + } + + // Special .5 density cases + if (resource->resource_mapping.density == srslte_csi_rs_resource_mapping_density_dot5_even || + resource->resource_mapping.density == srslte_csi_rs_resource_mapping_density_dot5_odd) { + // Increase the start by one if: + // - Even and starts with odd + // - Odd and starts with even + if ((resource->resource_mapping.density == srslte_csi_rs_resource_mapping_density_dot5_even && rb_begin % 2 == 1) || + (resource->resource_mapping.density == srslte_csi_rs_resource_mapping_density_dot5_odd && rb_begin % 2 == 0)) { + rb_begin++; + } + + // Skip one RB + rb_stride = 2; + } + + for (int l_idx = 0; l_idx < nof_l; l_idx++) { + // Get symbol index + uint32_t l = l_list[l_idx]; + + // Initialise sequence for this OFDM symbol + uint32_t cinit = csi_rs_cinit(carrier, slot_cfg, resource, l); + srslte_sequence_state_t sequence_state = {}; + srslte_sequence_state_init(&sequence_state, cinit); + + // Skip unallocated RB + srslte_sequence_state_advance(&sequence_state, 2 * csi_rs_count(resource->resource_mapping.density, rb_begin)); + + // Temporal R sequence + cf_t r[64]; + uint32_t r_idx = 64; + + // Iterate over frequency domain + for (uint32_t n = rb_begin; n < rb_end; n += rb_stride) { + for (uint32_t k_idx = 0; k_idx < nof_k; k_idx++) { + // Calculate sub-carrier index k + uint32_t k = SRSLTE_NRE * n + k_list[k_idx]; + + // Do we need more r? + if (r_idx >= 64) { + // ... Generate a bunch of it! + srslte_sequence_state_gen_f(&sequence_state, M_SQRT1_2 * beta, (float*)r, 64 * 2); + r_idx = 0; + } + + // Put CSI in grid + grid[l * SRSLTE_NRE * carrier->nof_prb + k] = r[r_idx++]; + } + } + } + + return SRSLTE_SUCCESS; +} + +int srslte_csi_rs_nzp_measure(const srslte_carrier_nr_t* carrier, + const srslte_dl_slot_cfg_t* slot_cfg, + const srslte_csi_rs_nzp_resource_t* resource, + const cf_t* grid, + srslte_csi_rs_measure_t* measure) +{ + if (carrier == NULL || resource == NULL || grid == NULL) { + return SRSLTE_ERROR; + } + + uint32_t k_list[CSI_RS_MAX_CDM_GROUP]; + int nof_k = csi_rs_location_get_k_list(&resource->resource_mapping, k_list); + if (nof_k <= 0) { + return SRSLTE_ERROR; + } + + uint32_t l_list[CSI_RS_MAX_CDM_GROUP]; + int nof_l = csi_rs_location_get_l_list(&resource->resource_mapping, l_list); + if (nof_l <= 0) { + return SRSLTE_ERROR; + } + + // Calculate Resource Block boundaries + uint32_t rb_begin = resource->resource_mapping.freq_band.start_rb; + uint32_t rb_end = resource->resource_mapping.freq_band.start_rb + resource->resource_mapping.freq_band.nof_rb; + uint32_t rb_stride = 1; + + // Calculate power allocation + float beta = srslte_convert_dB_to_amplitude((float)resource->power_control_offset); + if (!isnormal(beta)) { + beta = 1.0f; + } + + // Special .5 density cases + if (resource->resource_mapping.density == srslte_csi_rs_resource_mapping_density_dot5_even || + resource->resource_mapping.density == srslte_csi_rs_resource_mapping_density_dot5_odd) { + // Increase the start by one if: + // - Even and starts with odd + // - Odd and starts with even + if ((resource->resource_mapping.density == srslte_csi_rs_resource_mapping_density_dot5_even && rb_begin % 2 == 1) || + (resource->resource_mapping.density == srslte_csi_rs_resource_mapping_density_dot5_odd && rb_begin % 2 == 0)) { + rb_begin++; + } + + // Skip one RB + rb_stride = 2; + } + + // Accumulators + float epre_acc = 0.0f; + cf_t rsrp_acc = 0.0f; + uint32_t count = 0; + + for (int l_idx = 0; l_idx < nof_l; l_idx++) { + // Get symbol index + uint32_t l = l_list[l_idx]; + + // Initialise sequence for this OFDM symbol + uint32_t cinit = csi_rs_cinit(carrier, slot_cfg, resource, l); + srslte_sequence_state_t sequence_state = {}; + srslte_sequence_state_init(&sequence_state, cinit); + + // Skip unallocated RB + srslte_sequence_state_advance(&sequence_state, 2 * csi_rs_count(resource->resource_mapping.density, rb_begin)); + + // Temporal R sequence + cf_t r[64]; + uint32_t r_idx = 64; + + // Iterate over frequency domain + for (uint32_t n = rb_begin; n < rb_end; n += rb_stride) { + for (uint32_t k_idx = 0; k_idx < nof_k; k_idx++) { + // Calculate sub-carrier index k + uint32_t k = SRSLTE_NRE * n + k_list[k_idx]; + + // Do we need more r? + if (r_idx >= 64) { + // ... Generate a bunch of it! + srslte_sequence_state_gen_f(&sequence_state, M_SQRT1_2 / beta, (float*)r, 64 * 2); + r_idx = 0; + } + + // Take CSI-RS from grid and measure + cf_t tmp = grid[l * SRSLTE_NRE * carrier->nof_prb + k] * conjf(r[r_idx++]); + rsrp_acc += tmp; + epre_acc = __real__ tmp * __real__ tmp + __imag__ tmp * __imag__ tmp; + count++; + } + } + } + + if (count) { + measure->epre = epre_acc / (float)count; + measure->rsrp = cabsf(rsrp_acc) / (float)count; + } + return SRSLTE_SUCCESS; } \ No newline at end of file