diff --git a/lib/include/srslte/phy/ch_estimation/ul_rs_tables.h b/lib/include/srslte/phy/ch_estimation/ul_rs_tables.h index ea2f91086..41c44a491 100644 --- a/lib/include/srslte/phy/ch_estimation/ul_rs_tables.h +++ b/lib/include/srslte/phy/ch_estimation/ul_rs_tables.h @@ -16,67 +16,54 @@ #include // Phi values for M_sc=12 Table 5.5.1.2-1 in 36.211 -static const int phi_M_sc_12[30][12] = {{-1, 1, 3, -3, 3, 3, 1, 1, 3, 1, -3, 3}, {1, 1, 3, 3, 3, -1, 1, -3, -3, 1, -3, 3}, - {1, 1, -3, -3, -3, -1, -3, -3, 1, -3, 1, -1}, {-1, 1, 1, 1, 1, -1, -3, -3, 1, -3, 3, -1}, - {-1, 3, 1, -1, 1, -1, -3, -1, 1, -1, 1, 3}, {1, -3, 3, -1, -1, 1, 1, -1, -1, 3, -3, 1}, - {-1, 3, -3, -3, -3, 3, 1, -1, 3, 3, -3, 1}, {-3, -1, -1, -1, 1, -3, 3, -1, 1, -3, 3, 1}, - {1, -3, 3, 1, -1, -1, -1, 1, 1, 3, -1, 1}, {1, -3, -1, 3, 3, -1, -3, 1, 1, 1, 1, 1}, - {-1, 3, -1, 1, 1, -3, -3, -1, -3, -3, 3, -1}, {3, 1, -1, -1, 3, 3, -3, 1, 3, 1, 3, 3}, - {1, -3, 1, 1, -3, 1, 1, 1, -3, -3, -3, 1}, {3, 3, -3, 3, -3, 1, 1, 3, -1, -3, 3, 3}, - {-3, 1, -1, -3, -1, 3, 1, 3, 3, 3, -1, 1}, {3, -1, 1, -3, -1, -1, 1, 1, 3, 1, -1, -3}, - {1, 3, 1, -1, 1, 3, 3, 3, -1, -1, 3, -1}, {-3, 1, 1, 3, -3, 3, -3, -3, 3, 1, 3, -1}, - {-3, 3, 1, 1, -3, 1, -3, -3, -1, -1, 1, -3}, {-1, 3, 1, 3, 1, -1, -1, 3, -3, -1, -3, -1}, - {-1, -3, 1, 1, 1, 1, 3, 1, -1, 1, -3, -1}, {-1, 3, -1, 1, -3, -3, -3, -3, -3, 1, -1, -3}, - {1, 1, -3, -3, -3, -3, -1, 3, -3, 1, -3, 3}, {1, 1, -1, -3, -1, -3, 1, -1, 1, 3, -1, 1}, - {1, 1, 3, 1, 3, 3, -1, 1, -1, -3, -3, 1}, {1, -3, 3, 3, 1, 3, 3, 1, -3, -1, -1, 3}, - {1, 3, -3, -3, 3, -3, 1, -1, -1, 3, -1, -3}, {-3, -1, -3, -1, -3, 3, 1, -1, 1, 3, -3, -3}, - {-1, 3, -3, 3, -1, 3, 3, -3, 3, 3, -1, -1}, {3, -3, -3, -1, -1, -3, -1, 3, -3, 3, 1, -1}}; +static const int phi_M_sc_12[30][12] = { + {-1, 1, 3, -3, 3, 3, 1, 1, 3, 1, -3, 3}, {1, 1, 3, 3, 3, -1, 1, -3, -3, 1, -3, 3}, + {1, 1, -3, -3, -3, -1, -3, -3, 1, -3, 1, -1}, {-1, 1, 1, 1, 1, -1, -3, -3, 1, -3, 3, -1}, + {-1, 3, 1, -1, 1, -1, -3, -1, 1, -1, 1, 3}, {1, -3, 3, -1, -1, 1, 1, -1, -1, 3, -3, 1}, + {-1, 3, -3, -3, -3, 3, 1, -1, 3, 3, -3, 1}, {-3, -1, -1, -1, 1, -3, 3, -1, 1, -3, 3, 1}, + {1, -3, 3, 1, -1, -1, -1, 1, 1, 3, -1, 1}, {1, -3, -1, 3, 3, -1, -3, 1, 1, 1, 1, 1}, + {-1, 3, -1, 1, 1, -3, -3, -1, -3, -3, 3, -1}, {3, 1, -1, -1, 3, 3, -3, 1, 3, 1, 3, 3}, + {1, -3, 1, 1, -3, 1, 1, 1, -3, -3, -3, 1}, {3, 3, -3, 3, -3, 1, 1, 3, -1, -3, 3, 3}, + {-3, 1, -1, -3, -1, 3, 1, 3, 3, 3, -1, 1}, {3, -1, 1, -3, -1, -1, 1, 1, 3, 1, -1, -3}, + {1, 3, 1, -1, 1, 3, 3, 3, -1, -1, 3, -1}, {-3, 1, 1, 3, -3, 3, -3, -3, 3, 1, 3, -1}, + {-3, 3, 1, 1, -3, 1, -3, -3, -1, -1, 1, -3}, {-1, 3, 1, 3, 1, -1, -1, 3, -3, -1, -3, -1}, + {-1, -3, 1, 1, 1, 1, 3, 1, -1, 1, -3, -1}, {-1, 3, -1, 1, -3, -3, -3, -3, -3, 1, -1, -3}, + {1, 1, -3, -3, -3, -3, -1, 3, -3, 1, -3, 3}, {1, 1, -1, -3, -1, -3, 1, -1, 1, 3, -1, 1}, + {1, 1, 3, 1, 3, 3, -1, 1, -1, -3, -3, 1}, {1, -3, 3, 3, 1, 3, 3, 1, -3, -1, -1, 3}, + {1, 3, -3, -3, 3, -3, 1, -1, -1, 3, -1, -3}, {-3, -1, -3, -1, -3, 3, 1, -1, 1, 3, -3, -3}, + {-1, 3, -3, 3, -1, 3, 3, -3, 3, 3, -1, -1}, {3, -3, -3, -1, -1, -3, -1, 3, -3, 3, 1, -1}}; // Phi values for M_sc=24 Table 5.5.1.2-2 in 36.211 -static const int phi_M_sc_24[30][24] = {{-1, 3, 1, -3, 3, -1, 1, 3, -3, 3, 1, 3, -3, 3, 1, 1, -1, 1, 3, -3, 3, -3, -1, -3}, - {-3, 3, -3, -3, -3, 1, -3, -3, 3, -1, 1, 1, 1, 3, 1, -1, 3, -3, -3, 1, 3, 1, 1, -3}, - {3, -1, 3, 3, 1, 1, -3, 3, 3, 3, 3, 1, -1, 3, -1, 1, 1, -1, -3, -1, -1, 1, 3, 3}, - {-1, -3, 1, 1, 3, -3, 1, 1, -3, -1, -1, 1, 3, 1, 3, 1, -1, 3, 1, 1, -3, -1, -3, -1}, - {-1, -1, -1, -3, -3, -1, 1, 1, 3, 3, -1, 3, -1, 1, -1, -3, 1, -1, -3, -3, 1, -3, -1, -1}, - {-3, 1, 1, 3, -1, 1, 3, 1, -3, 1, -3, 1, 1, -1, -1, 3, -1, -3, 3, -3, -3, -3, 1, 1}, - {1, 1, -1, -1, 3, -3, -3, 3, -3, 1, -1, -1, 1, -1, 1, 1, -1, -3, -1, 1, -1, 3, -1, -3}, - {-3, 3, 3, -1, -1, -3, -1, 3, 1, 3, 1, 3, 1, 1, -1, 3, 1, -1, 1, 3, -3, -1, -1, 1}, - {-3, 1, 3, -3, 1, -1, -3, 3, -3, 3, -1, -1, -1, -1, 1, -3, -3, -3, 1, -3, -3, -3, 1, -3}, - {1, 1, -3, 3, 3, -1, -3, -1, 3, -3, 3, 3, 3, -1, 1, 1, -3, 1, -1, 1, 1, -3, 1, 1}, - {-1, 1, -3, -3, 3, -1, 3, -1, -1, -3, -3, -3, -1, -3, -3, 1, -1, 1, 3, 3, -1, 1, -1, 3}, - {1, 3, 3, -3, -3, 1, 3, 1, -1, -3, -3, -3, 3, 3, -3, 3, 3, -1, -3, 3, -1, 1, -3, 1}, - {1, 3, 3, 1, 1, 1, -1, -1, 1, -3, 3, -1, 1, 1, -3, 3, 3, -1, -3, 3, -3, -1, -3, -1}, - {3, -1, -1, -1, -1, -3, -1, 3, 3, 1, -1, 1, 3, 3, 3, -1, 1, 1, -3, 1, 3, -1, -3, 3}, - {-3, -3, 3, 1, 3, 1, -3, 3, 1, 3, 1, 1, 3, 3, -1, -1, -3, 1, -3, -1, 3, 1, 1, 3}, - {-1, -1, 1, -3, 1, 3, -3, 1, -1, -3, -1, 3, 1, 3, 1, -1, -3, -3, -1, -1, -3, -3, -3, -1}, - {-1, -3, 3, -1, -1, -1, -1, 1, 1, -3, 3, 1, 3, 3, 1, -1, 1, -3, 1, -3, 1, 1, -3, -1}, - {1, 3, -1, 3, 3, -1, -3, 1, -1, -3, 3, 3, 3, -1, 1, 1, 3, -1, -3, -1, 3, -1, -1, -1}, - {1, 1, 1, 1, 1, -1, 3, -1, -3, 1, 1, 3, -3, 1, -3, -1, 1, 1, -3, -3, 3, 1, 1, -3}, - {1, 3, 3, 1, -1, -3, 3, -1, 3, 3, 3, -3, 1, -1, 1, -1, -3, -1, 1, 3, -1, 3, -3, -3}, - {-1, -3, 3, -3, -3, -3, -1, -1, -3, -1, -3, 3, 1, 3, -3, -1, 3, -1, 1, -1, 3, -3, 1, -1}, - {-3, -3, 1, 1, -1, 1, -1, 1, -1, 3, 1, -3, -1, 1, -1, 1, -1, -1, 3, 3, -3, -1, 1, -3}, - {-3, -1, -3, 3, 1, -1, -3, -1, -3, -3, 3, -3, 3, -3, -1, 1, 3, 1, -3, 1, 3, 3, -1, -3}, - {-1, -1, -1, -1, 3, 3, 3, 1, 3, 3, -3, 1, 3, -1, 3, -1, 3, 3, -3, 3, 1, -1, 3, 3}, - {1, -1, 3, 3, -1, -3, 3, -3, -1, -1, 3, -1, 3, -1, -1, 1, 1, 1, 1, -1, -1, -3, -1, 3}, - {1, -1, 1, -1, 3, -1, 3, 1, 1, -1, -1, -3, 1, 1, -3, 1, 3, -3, 1, 1, -3, -3, -1, -1}, - {-3, -1, 1, 3, 1, 1, -3, -1, -1, -3, 3, -3, 3, 1, -3, 3, -3, 1, -1, 1, -3, 1, 1, 1}, - {-1, -3, 3, 3, 1, 1, 3, -1, -3, -1, -1, -1, 3, 1, -3, -3, -1, 3, -3, -1, -3, -1, -3, -1}, - {-1, -3, -1, -1, 1, -3, -1, -1, 1, -1, -3, 1, 1, -3, 1, -3, -3, 3, 1, 1, -1, 3, -1, -1}, - {1, 1, -1, -1, -3, -1, 3, -1, 3, -1, 1, 3, 1, -1, 3, 1, 3, -3, -3, 1, -1, -1, 1, 3}}; - -// Prime numbers used for Section 5.5.1.1 of 36.211 -#define NOF_PRIME_NUMBERS 196 -static const uint32_t prime_numbers[NOF_PRIME_NUMBERS] = { - 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, - 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, - 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, - 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, - 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, - 467, 479, 487, 491, 499, 503, 509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, - 599, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691, 701, - 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827, - 829, 839, 853, 857, 859, 863, 877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, - 967, 971, 977, 983, 991, 997, 1009, 1013, 1019, 1021, 1031, 1033, 1039, 1049, 1051, 1061, 1063, 1069, - 1087, 1091, 1093, 1097, 1103, 1109, 1117, 1123, 1129, 1151, 1153, 1163, 1171, 1181, 1187, 1193}; +static const int phi_M_sc_24[30][24] = { + {-1, 3, 1, -3, 3, -1, 1, 3, -3, 3, 1, 3, -3, 3, 1, 1, -1, 1, 3, -3, 3, -3, -1, -3}, + {-3, 3, -3, -3, -3, 1, -3, -3, 3, -1, 1, 1, 1, 3, 1, -1, 3, -3, -3, 1, 3, 1, 1, -3}, + {3, -1, 3, 3, 1, 1, -3, 3, 3, 3, 3, 1, -1, 3, -1, 1, 1, -1, -3, -1, -1, 1, 3, 3}, + {-1, -3, 1, 1, 3, -3, 1, 1, -3, -1, -1, 1, 3, 1, 3, 1, -1, 3, 1, 1, -3, -1, -3, -1}, + {-1, -1, -1, -3, -3, -1, 1, 1, 3, 3, -1, 3, -1, 1, -1, -3, 1, -1, -3, -3, 1, -3, -1, -1}, + {-3, 1, 1, 3, -1, 1, 3, 1, -3, 1, -3, 1, 1, -1, -1, 3, -1, -3, 3, -3, -3, -3, 1, 1}, + {1, 1, -1, -1, 3, -3, -3, 3, -3, 1, -1, -1, 1, -1, 1, 1, -1, -3, -1, 1, -1, 3, -1, -3}, + {-3, 3, 3, -1, -1, -3, -1, 3, 1, 3, 1, 3, 1, 1, -1, 3, 1, -1, 1, 3, -3, -1, -1, 1}, + {-3, 1, 3, -3, 1, -1, -3, 3, -3, 3, -1, -1, -1, -1, 1, -3, -3, -3, 1, -3, -3, -3, 1, -3}, + {1, 1, -3, 3, 3, -1, -3, -1, 3, -3, 3, 3, 3, -1, 1, 1, -3, 1, -1, 1, 1, -3, 1, 1}, + {-1, 1, -3, -3, 3, -1, 3, -1, -1, -3, -3, -3, -1, -3, -3, 1, -1, 1, 3, 3, -1, 1, -1, 3}, + {1, 3, 3, -3, -3, 1, 3, 1, -1, -3, -3, -3, 3, 3, -3, 3, 3, -1, -3, 3, -1, 1, -3, 1}, + {1, 3, 3, 1, 1, 1, -1, -1, 1, -3, 3, -1, 1, 1, -3, 3, 3, -1, -3, 3, -3, -1, -3, -1}, + {3, -1, -1, -1, -1, -3, -1, 3, 3, 1, -1, 1, 3, 3, 3, -1, 1, 1, -3, 1, 3, -1, -3, 3}, + {-3, -3, 3, 1, 3, 1, -3, 3, 1, 3, 1, 1, 3, 3, -1, -1, -3, 1, -3, -1, 3, 1, 1, 3}, + {-1, -1, 1, -3, 1, 3, -3, 1, -1, -3, -1, 3, 1, 3, 1, -1, -3, -3, -1, -1, -3, -3, -3, -1}, + {-1, -3, 3, -1, -1, -1, -1, 1, 1, -3, 3, 1, 3, 3, 1, -1, 1, -3, 1, -3, 1, 1, -3, -1}, + {1, 3, -1, 3, 3, -1, -3, 1, -1, -3, 3, 3, 3, -1, 1, 1, 3, -1, -3, -1, 3, -1, -1, -1}, + {1, 1, 1, 1, 1, -1, 3, -1, -3, 1, 1, 3, -3, 1, -3, -1, 1, 1, -3, -3, 3, 1, 1, -3}, + {1, 3, 3, 1, -1, -3, 3, -1, 3, 3, 3, -3, 1, -1, 1, -1, -3, -1, 1, 3, -1, 3, -3, -3}, + {-1, -3, 3, -3, -3, -3, -1, -1, -3, -1, -3, 3, 1, 3, -3, -1, 3, -1, 1, -1, 3, -3, 1, -1}, + {-3, -3, 1, 1, -1, 1, -1, 1, -1, 3, 1, -3, -1, 1, -1, 1, -1, -1, 3, 3, -3, -1, 1, -3}, + {-3, -1, -3, 3, 1, -1, -3, -1, -3, -3, 3, -3, 3, -3, -1, 1, 3, 1, -3, 1, 3, 3, -1, -3}, + {-1, -1, -1, -1, 3, 3, 3, 1, 3, 3, -3, 1, 3, -1, 3, -1, 3, 3, -3, 3, 1, -1, 3, 3}, + {1, -1, 3, 3, -1, -3, 3, -3, -1, -1, 3, -1, 3, -1, -1, 1, 1, 1, 1, -1, -1, -3, -1, 3}, + {1, -1, 1, -1, 3, -1, 3, 1, 1, -1, -1, -3, 1, 1, -3, 1, 3, -3, 1, 1, -3, -3, -1, -1}, + {-3, -1, 1, 3, 1, 1, -3, -1, -1, -3, 3, -3, 3, 1, -3, 3, -3, 1, -1, 1, -3, 1, 1, 1}, + {-1, -3, 3, 3, 1, 1, 3, -1, -3, -1, -1, -1, 3, 1, -3, -3, -1, 3, -3, -1, -3, -1, -3, -1}, + {-1, -3, -1, -1, 1, -3, -1, -1, 1, -1, -3, 1, 1, -3, 1, -3, -3, 3, 1, 1, -1, 3, -1, -1}, + {1, 1, -1, -1, -3, -1, 3, -1, 3, -1, 1, 3, 1, -1, 3, 1, 3, -3, -3, 1, -1, -1, 1, 3}}; #endif \ No newline at end of file diff --git a/lib/include/srslte/phy/utils/primes.h b/lib/include/srslte/phy/utils/primes.h new file mode 100644 index 000000000..96600810f --- /dev/null +++ b/lib/include/srslte/phy/utils/primes.h @@ -0,0 +1,34 @@ +/** + * + * \section COPYRIGHT + * + * Copyright 2013-2020 Software Radio Systems Limited + * + * By using this file, you agree to the terms and conditions set + * forth in the LICENSE file which can be found at the top level of + * the distribution. + * + */ + +#ifndef SRSLTE_PRIMES_H +#define SRSLTE_PRIMES_H + +#include "srslte/config.h" +#include + +/** + * @brief Finds the smallest prime number greater than n + * @param[in] n Provide the number + * @return A prime number below 1193, SRSLTE_ERROR code otherwise + */ +SRSLTE_API int srslte_prime_greater_than(uint32_t n); + +/** + * @brief Finds the biggest prime number lesser than n + * @attention the maximum prime number it can return is 1193 + * @param[in] n Provide the number + * @return A prime number below 1193, SRSLTE_ERROR code otherwise + */ +SRSLTE_API int srslte_prime_lower_than(uint32_t n); + +#endif // SRSLTE_PRIMES_H diff --git a/lib/src/phy/ch_estimation/chest_sl.c b/lib/src/phy/ch_estimation/chest_sl.c index 82eb15e34..20a49a7cc 100644 --- a/lib/src/phy/ch_estimation/chest_sl.c +++ b/lib/src/phy/ch_estimation/chest_sl.c @@ -20,6 +20,7 @@ #include "srslte/phy/ch_estimation/refsignal_ul.h" #include "srslte/phy/mimo/precoding.h" #include "srslte/phy/utils/debug.h" +#include "srslte/phy/utils/primes.h" #include "srslte/phy/utils/vector.h" static int chest_sl_init(srslte_chest_sl_t* q, uint32_t nof_cyclic_shift_seq) @@ -120,13 +121,12 @@ static int chest_sl_psbch_gen(srslte_chest_sl_t* q) u[ns] = (f_gh + f_ss) % SRSLTE_SL_N_RU_SEQ; } - int32_t N_zc = prime_numbers[0]; // N_zc - Zadoff Chu Sequence Length - for (uint32_t i = NOF_PRIME_NUMBERS - 1; i > 0; i--) { - if (prime_numbers[i] < q->M_sc_rs) { - N_zc = prime_numbers[i]; - break; - } + int32_t N_zc = srslte_prime_lower_than(q->M_sc_rs); // N_zc - Zadoff Chu Sequence Length + if (N_zc < SRSLTE_SUCCESS) { + ERROR("Could not find prime number\n"); + return SRSLTE_ERROR; } + for (int j = 0; j < q->nof_dmrs_symbols; ++j) { q->q[j] = srslte_refsignal_get_q(u[j], SRSLTE_SL_BASE_SEQUENCE_NUMBER, N_zc); float n_sz = (float)N_zc; @@ -358,11 +358,10 @@ static int chest_sl_pscch_gen(srslte_chest_sl_t* q, uint32_t cyclic_shift) } break; default: - for (uint32_t i = NOF_PRIME_NUMBERS - 1; i > 0; i--) { - if (prime_numbers[i] < q->M_sc_rs) { - N_zc = prime_numbers[i]; - break; - } + N_zc = srslte_prime_lower_than(q->M_sc_rs); // N_zc - Zadoff Chu Sequence Length + if (N_zc < SRSLTE_SUCCESS) { + ERROR("Could not find prime number\n"); + return SRSLTE_ERROR; } for (int j = 0; j < q->nof_dmrs_symbols; ++j) { q->q[j] = srslte_refsignal_get_q(u[j], SRSLTE_SL_BASE_SEQUENCE_NUMBER, N_zc); @@ -585,11 +584,10 @@ static int chest_sl_pssch_gen(srslte_chest_sl_t* q) } break; default: - for (uint32_t i = NOF_PRIME_NUMBERS - 1; i > 0; i--) { - if (prime_numbers[i] < q->M_sc_rs) { - N_zc = prime_numbers[i]; - break; - } + N_zc = srslte_prime_lower_than(q->M_sc_rs); // N_zc - Zadoff Chu Sequence Length + if (N_zc < SRSLTE_SUCCESS) { + ERROR("Could not find prime number\n"); + return SRSLTE_ERROR; } for (int j = 0; j < q->nof_dmrs_symbols; ++j) { q->q[j] = srslte_refsignal_get_q(u[j], SRSLTE_SL_BASE_SEQUENCE_NUMBER, N_zc); diff --git a/lib/src/phy/ch_estimation/refsignal_ul.c b/lib/src/phy/ch_estimation/refsignal_ul.c index eea61b3d1..e2f532ba5 100644 --- a/lib/src/phy/ch_estimation/refsignal_ul.c +++ b/lib/src/phy/ch_estimation/refsignal_ul.c @@ -22,6 +22,7 @@ #include "srslte/phy/dft/dft_precoding.h" #include "srslte/phy/phch/pucch.h" #include "srslte/phy/utils/debug.h" +#include "srslte/phy/utils/primes.h" #include "srslte/phy/utils/vector.h" // n_dmrs_2 table 5.5.2.1.1-1 from 36.211 @@ -204,17 +205,6 @@ int srslte_refsignal_ul_set_cell(srslte_refsignal_ul_t* q, srslte_cell_t cell) return ret; } -static uint32_t largest_prime_lower_than(uint32_t x) -{ - /* get largest prime n_zc 0; i--) { - if (prime_numbers[i] < x) { - return prime_numbers[i]; - } - } - return 0; -} - static void arg_r_uv_2prb(float* arg, uint32_t u) { for (int i = 0; i < 2 * SRSLTE_NRE; i++) { @@ -239,8 +229,7 @@ uint32_t srslte_refsignal_get_q(uint32_t u, uint32_t v, uint32_t N_sz) static void arg_r_uv_mprb(float* arg, uint32_t M_sc, uint32_t u, uint32_t v) { - - uint32_t N_sz = largest_prime_lower_than(M_sc); + int32_t N_sz = srslte_prime_lower_than(M_sc); // N_zc - Zadoff Chu Sequence Length if (N_sz > 0) { float q = srslte_refsignal_get_q(u, v, N_sz); float n_sz = (float)N_sz; diff --git a/lib/src/phy/utils/primes.c b/lib/src/phy/utils/primes.c new file mode 100644 index 000000000..03eb64cd6 --- /dev/null +++ b/lib/src/phy/utils/primes.c @@ -0,0 +1,55 @@ +/** + * + * \section COPYRIGHT + * + * Copyright 2013-2020 Software Radio Systems Limited + * + * By using this file, you agree to the terms and conditions set + * forth in the LICENSE file which can be found at the top level of + * the distribution. + * + */ + +#include "srslte/phy/utils/primes.h" + +#define NOF_PRIME_NUMBERS 196 + +static const uint32_t prime_numbers[NOF_PRIME_NUMBERS] = { + 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, + 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, + 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, + 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, + 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, + 467, 479, 487, 491, 499, 503, 509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, + 599, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691, 701, + 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827, + 829, 839, 853, 857, 859, 863, 877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, + 967, 971, 977, 983, 991, 997, 1009, 1013, 1019, 1021, 1031, 1033, 1039, 1049, 1051, 1061, 1063, 1069, + 1087, 1091, 1093, 1097, 1103, 1109, 1117, 1123, 1129, 1151, 1153, 1163, 1171, 1181, 1187, 1193}; + +int srslte_prime_greater_than(uint32_t n) +{ + for (uint32_t i = 0; i < NOF_PRIME_NUMBERS; i++) { + if (prime_numbers[i] > n) { + return n; + } + } + + return SRSLTE_ERROR_OUT_OF_BOUNDS; +} + +int srslte_prime_lower_than(uint32_t n) +{ + + if (n > prime_numbers[NOF_PRIME_NUMBERS - 1]) { + return SRSLTE_ERROR_OUT_OF_BOUNDS; + } + + for (uint32_t i = NOF_PRIME_NUMBERS - 1; i > 0; i--) { + if (prime_numbers[i] < n) { + return n; + } + } + + return 2; +}