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[Fix] Correct SNR calculation logic #437

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[Fix] Correct SNR calculation logic #437

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2 changes: 2 additions & 0 deletions files/config/ci/tddconfig-sim-ul.json
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,8 @@
"bs_server_addr": "127.0.0.1",
"bs_rru_addr": "127.0.0.1",
"fft_size": 2048,
"max_frame": 100,
"noise_level": 0.03,/*33.7db*/
"ofdm_data_num": 1200,
"demul_block_size": 64,
"freq_orthogonal_pilot": true,
Expand Down
137 changes: 132 additions & 5 deletions src/data_generator/test_vector_generator.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -258,6 +258,11 @@ static void GenerateTestVectors(Config* cfg, const std::string& profile_flag) {
for (size_t sched = 0; sched < sched_ue_set.size(); sched++) {
auto sched_id = sched_ue_set.at(sched);
auto ue_map = Utils::Int2Bits(sched_id, cfg->UeAntNum());
// std::cout << "ue_map = ";
// for (size_t i = 0; i < ue_map.n_elem; i++) {
// std::cout << ue_map(i) << " ";
// }
// std::cout << std::endl;
AGORA_LOG_INFO(
"Frame Schedule %zu: Generating data for %zu UEs with UL MCS %zu & DL "
"MCS %zu\n",
Expand Down Expand Up @@ -372,6 +377,36 @@ static void GenerateTestVectors(Config* cfg, const std::string& profile_flag) {
cfg, ofdm_symbol, nullptr, SymbolType::kUL);
}

// ========== 输出中间生成数据 ==========
if (sched == 0) {
std::cout << "\n========== UL Data Generation Pipeline (First Data Symbol, First UE) ==========\n";
size_t sample_idx = 0; // 第一个数据符号的第一个UE

// 1. 编码数据 (ul_encoded_codewords) - 前20个字节
std::cout << "\n1. Encoded Codewords (first 20 bytes):\n ";
for (size_t i = 0; i < std::min(20UL, ul_encoded_codewords.at(sample_idx).size()); i++) {
std::printf("%02X ", static_cast<uint8_t>(ul_encoded_codewords.at(sample_idx).at(i)));
}
std::cout << "\n Total encoded bytes: " << ul_encoded_codewords.at(sample_idx).size() << "\n";

// 2. 调制符号 (ul_modulated_symbols) - 前10个符号
std::cout << "\n2. Modulated Symbols (first 10 complex symbols):\n ";
for (size_t i = 0; i < std::min(10UL, ul_modulated_symbols.at(sample_idx).size()); i++) {
complex_float sym = ul_modulated_symbols.at(sample_idx).at(i);
std::printf("[%.4f%+.4fi] ", sym.re, sym.im);
}
std::cout << "\n Total modulated symbols: " << ul_modulated_symbols.at(sample_idx).size() << "\n";

// 计算调制符号的平均功率
float total_power = 0.0f;
for (const auto& sym : ul_modulated_symbols.at(sample_idx)) {
total_power += (sym.re * sym.re + sym.im * sym.im);
}
float avg_power = total_power / ul_modulated_symbols.at(sample_idx).size();
std::cout << " Average symbol power: " << avg_power << "\n";
std::cout << " Average symbol magnitude: " << std::sqrt(avg_power) << "\n";
}

// Place modulated uplink data codewords into central IFFT bins
RtAssert(ul_ldpc_config.NumBlocksInSymbol() == 1); // TODO: Assumption
std::vector<std::vector<complex_float>> pre_ifft_data_syms;
Expand All @@ -380,6 +415,34 @@ static void GenerateTestVectors(Config* cfg, const std::string& profile_flag) {
pre_ifft_data_syms.at(i) =
DataGenerator::BinForIfft(cfg, ul_modulated_symbols.at(i));
}

// 输出 OFDM 映射后的数据
if (sched == 0) {
size_t sample_idx = 0;
std::cout << "\n3. After OFDM Mapping (BinForIfft) - Frequency domain:\n";
std::cout << " Total subcarriers: " << pre_ifft_data_syms.at(sample_idx).size() << "\n";

// 统计非零子载波
size_t non_zero_count = 0;
float total_power = 0.0f;
for (const auto& sc : pre_ifft_data_syms.at(sample_idx)) {
if (sc.re != 0.0f || sc.im != 0.0f) {
non_zero_count++;
total_power += (sc.re * sc.re + sc.im * sc.im);
}
}
std::cout << " Non-zero subcarriers: " << non_zero_count << "\n";
std::cout << " Average power (non-zero): " << (non_zero_count > 0 ? total_power/non_zero_count : 0.0f) << "\n";

// 显示数据子载波范围内的前10个
std::cout << " First 10 data subcarriers (starting from OfdmDataStart=" << cfg->OfdmDataStart() << "):\n ";
for (size_t i = cfg->OfdmDataStart(); i < cfg->OfdmDataStart() + 10 && i < pre_ifft_data_syms.at(sample_idx).size(); i++) {
complex_float sc = pre_ifft_data_syms.at(sample_idx).at(i);
std::printf("[%.4f%+.4fi] ", sc.re, sc.im);
}
std::cout << "\n";
std::cout << "============================================================\n\n";
}

{
if (kPrintFreqDomainSamples) {
Expand Down Expand Up @@ -465,7 +528,11 @@ static void GenerateTestVectors(Config* cfg, const std::string& profile_flag) {
std::to_string(cfg->UeAntNum()) + ".bin";
AGORA_LOG_INFO("Saving uplink rx samples to %s\n", filename_rx.c_str());
auto ue_map_mat = arma::repmat(ue_map, cfg->BsAntNum(), 1);
for (size_t i = 0; i < cfg->Frame().NumTotalSyms(); i++) {
// Normalize transmit power by sqrt(num_ues) to maintain constant total power

float snr_sum = 0.0f;
size_t snr_count = 0;
for (size_t i = 0; i < cfg->Frame().NumTotalSyms(); i++) {//cfg->Frame().NumTotalSyms(): 128
arma::cx_fmat mat_input_data(
reinterpret_cast<arma::cx_float*>(tx_data_all_symbols[i]),
cfg->OfdmCaNum(), cfg->UeAntNum(), false);
Expand All @@ -477,13 +544,73 @@ static void GenerateTestVectors(Config* cfg, const std::string& profile_flag) {
arma::cx_fmat mat_csi(
reinterpret_cast<arma::cx_float*>(csi_matrices[j]), cfg->BsAntNum(),
cfg->UeAntNum(), false);
mat_output.row(j) =
(mat_input_data.row(j) % ue_map) * (mat_csi % ue_map_mat).st();
mat_output.row(j) = (mat_input_data.row(j) % ue_map) * (mat_csi % ue_map_mat).st();
}

// Save Hx (signal before noise) for output
arma::cx_fmat Hx_signal = mat_output;

arma::cx_fmat noise_mat(size(mat_output));
noise_mat.set_real(arma::randn<arma::fmat>(size(real(mat_output))));
noise_mat.set_imag(arma::randn<arma::fmat>(size(real(mat_output))));
mat_output += (noise_mat * cfg->NoiseLevel() * sqrt2_norm);

// Calculate scaled noise: n
arma::cx_fmat n_noise = noise_mat * cfg->NoiseLevel() * sqrt2_norm;
n_noise *= std::sqrt(static_cast<float>(cfg->UeAntNum()));
n_noise /= std::sqrt(static_cast<float>(cfg->PilotScGroupSize()));


// Calculate and output min/max SNR for frame 0
if (sched == 0) {
arma::fmat signal_power = arma::pow(arma::abs(mat_output), 2);
arma::fmat noise_power = arma::pow(arma::abs(n_noise), 2);

std::cout <<"symbol: "<< i<< " Frame 0 SNR (dB) Range at BS Antennas: " << std::fixed
<< std::setw(5) << std::setprecision(1);

size_t ue_id = 0; // First UE
float max_snr = -std::numeric_limits<float>::infinity();
float min_snr = std::numeric_limits<float>::infinity();
for (size_t ant_idx = 0; ant_idx < cfg->BsAntNum(); ant_idx++) {
// Calculate average SNR only over active data subcarriers
float total_signal = 0.0f;
float total_noise = 0.0f;

// Only calculate over data subcarriers (OfdmDataStart to OfdmDataStop)
for (size_t sc_idx = cfg->OfdmDataStart(); sc_idx < cfg->OfdmDataStop(); sc_idx++) {
total_signal += signal_power(sc_idx, ant_idx);
total_noise += noise_power(sc_idx, ant_idx);
}
// std::cout << "Ant " << ant_idx << "'s average SNR: "<< std::fixed << std::setprecision(1) << (snr_sum / active_sc_count) << " dB; ";
if (total_noise > 0) {
float snr_linear = total_signal / total_noise;
float snr_db = 10.0f * std::log10(snr_linear);
snr_sum+= snr_db;
snr_count++;
if (snr_db < min_snr) {
min_snr = snr_db;
}
if (snr_db > max_snr) {
max_snr = snr_db;
}
}
}


if (min_snr == std::numeric_limits<float>::infinity()) {
min_snr = -100.0f;
}
if (max_snr == -std::numeric_limits<float>::infinity()) {
max_snr = -100.0f;
}

std::cout << "User " << ue_id << ": [" << min_snr << "," << max_snr << "] ";
std::cout << std::endl;
}

// Add noise to signal: Hx + n
mat_output += n_noise;

for (size_t j = 0; j < cfg->BsAntNum(); j++) {
auto* this_ofdm_symbol = rx_data_all_symbols[i] + j * cfg->OfdmCaNum();
CommsLib::FFTShift(this_ofdm_symbol, cfg->OfdmCaNum());
Expand All @@ -497,7 +624,7 @@ static void GenerateTestVectors(Config* cfg, const std::string& profile_flag) {
rx_data_temp,
i != 0 || sched != 0); //Do not append in the first write
}

std::cout << "Average SNR: " << std::fixed << std::setprecision(1) << (snr_sum / snr_count) << " dB; ";
if (kDebugPrintRxData) {
std::printf("For %zu ue(s), rx data\n", sched_id);
for (size_t i = 0; i < 10; i++) {
Expand Down