Added vector estimate frequency

lib/include/srslte/phy/utils/simd.h

@@ -773,6 +773,23 @@ static inline simd_f_t srslte_simd_cf_re(simd_cf_t in) {
   return out;
 }
 
+static inline simd_f_t srslte_simd_cf_im(simd_cf_t in)
+{
+#ifdef HAVE_NEON
+  simd_f_t out = in.val[1];
+#else
+  simd_f_t out      = in.im;
+#endif /*HAVE_NEON*/
+#ifndef LV_HAVE_AVX512
+#ifdef LV_HAVE_AVX2
+  /* Permute for AVX registers (mis SSE registers) */
+  const __m256i idx = _mm256_setr_epi32(0, 2, 4, 6, 1, 3, 5, 7);
+  out               = _mm256_permutevar8x32_ps(out, idx);
+#endif /* LV_HAVE_AVX2 */
+#endif /* LV_HAVE_AVX512 */
+  return out;
+}
+
 static inline simd_cf_t srslte_simd_cf_set1 (cf_t x) {
   simd_cf_t ret;
 #ifdef LV_HAVE_AVX512

lib/include/srslte/phy/utils/vector.h

@@ -162,6 +162,7 @@ SRSLTE_API void srslte_vec_interleave_add(const cf_t *x, const cf_t *y, cf_t *z,
 
 SRSLTE_API void srslte_vec_apply_cfo(const cf_t *x, float cfo, cf_t *z, int len);
 
+SRSLTE_API float srslte_vec_estimate_frequency(const cf_t* x, int len);
 
 #ifdef __cplusplus
 }

lib/include/srslte/phy/utils/vector_simd.h

@@ -137,6 +137,7 @@ SRSLTE_API void srslte_vec_interleave_add_simd(const cf_t *x, const cf_t *y, cf_
 
 SRSLTE_API void srslte_vec_apply_cfo_simd(const cf_t *x, float cfo, cf_t *z, int len);
 
+SRSLTE_API float srslte_vec_estimate_frequency_simd(const cf_t* x, int len);
 
 /* SIMD Find Max functions */
 SRSLTE_API uint32_t srslte_vec_max_fi_simd(const float *x, const int len);

lib/src/phy/utils/test/vector_test.c

@@ -800,6 +800,16 @@ TEST(srslte_vec_apply_cfo,
          free(z);
 )
 
+TEST(srslte_vec_estimate_frequency, MALLOC(cf_t, x); float freq_gold = 0.1f; float freq = 0.1f;
+
+     for (int i = 0; i < block_size; i++) { x[i] = cexpf(-I * 2.0f * M_PI * (float)i * freq_gold); }
+
+     if (block_size > 6) {
+       TEST_CALL(freq = srslte_vec_estimate_frequency(x, block_size);)
+     } mse = cabsf(freq - freq_gold);
+
+     free(x);)
+
 TEST(srslte_cfo_correct,
      srslte_cfo_t srslte_cfo;
      bzero(&srslte_cfo, sizeof(srslte_cfo));
@@ -961,6 +971,10 @@ int main(int argc, char **argv) {
     passed[func_count][size_count] = test_srslte_vec_apply_cfo(func_names[func_count], &timmings[func_count][size_count], block_size);
     func_count++;
 
+    passed[func_count][size_count] =
+        test_srslte_vec_estimate_frequency(func_names[func_count], &timmings[func_count][size_count], block_size);
+    func_count++;
+
     passed[func_count][size_count] = test_srslte_cfo_correct(func_names[func_count], &timmings[func_count][size_count], block_size);
     func_count++;
 

lib/src/phy/utils/vector.c

@@ -467,3 +467,8 @@ void srslte_vec_interleave_add(const cf_t *x, const cf_t *y, cf_t *z, const int
 void srslte_vec_apply_cfo(const cf_t *x, float cfo, cf_t *z, int len) {
   srslte_vec_apply_cfo_simd(x, cfo, z, len);
 }
+
+float srslte_vec_estimate_frequency(const cf_t* x, int len)
+{
+  return srslte_vec_estimate_frequency_simd(x, len);
+}

lib/src/phy/utils/vector_simd.c

@@ -1557,3 +1557,54 @@ void srslte_vec_apply_cfo_simd(const cf_t *x, float cfo, cf_t *z, int len) {
   }
 }
 
+float srslte_vec_estimate_frequency_simd(const cf_t* x, int len)
+{
+  float sum_sin = 0.0f;
+
+  /* Asssumes x[n] = cexp(j·2·pi·n·O) = cos(j·2·pi·n·O) + j · sin(j·2·pi·n·O)
+   * where O = f / f_s */
+
+  int i = 1;
+
+#if SRSLTE_SIMD_CF_SIZE
+  simd_f_t _sum_sin = srslte_simd_f_zero();
+
+  for (; i < len - SRSLTE_SIMD_CF_SIZE + 1; i += SRSLTE_SIMD_CF_SIZE) {
+    simd_cf_t a1  = srslte_simd_cfi_loadu(&x[i]);
+    simd_f_t  re1 = srslte_simd_cf_re(a1);
+    simd_f_t  im1 = srslte_simd_cf_im(a1);
+
+    simd_cf_t a2  = srslte_simd_cfi_loadu(&x[i - 1]);
+    simd_f_t  re2 = srslte_simd_cf_re(a2);
+    simd_f_t  im2 = srslte_simd_cf_im(a2);
+
+    simd_f_t _pow = srslte_simd_f_sqrt(
+        srslte_simd_f_mul(srslte_simd_f_add(srslte_simd_f_mul(re1, re1), srslte_simd_f_mul(im1, im1)),
+                          srslte_simd_f_add(srslte_simd_f_mul(re2, re2), srslte_simd_f_mul(im2, im2))));
+
+    simd_f_t _sin = srslte_simd_f_mul(srslte_simd_f_sub(srslte_simd_f_mul(re1, im2), srslte_simd_f_mul(re2, im1)),
+                                      srslte_simd_f_rcp(_pow));
+    _sum_sin      = srslte_simd_f_add(_sum_sin, _sin);
+  }
+
+  float _sum_sin_v[SRSLTE_SIMD_CF_SIZE];
+  srslte_simd_f_storeu(_sum_sin_v, _sum_sin);
+  for (int k = 0; k < SRSLTE_SIMD_CF_SIZE; k++) {
+    sum_sin += _sum_sin_v[k];
+  }
+#endif /* SRSLTE_SIMD_CF_SIZE */
+
+  for (; i < len; i++) {
+    /* Load current Sample */
+    float re1 = crealf(x[i]);
+    float im1 = cimagf(x[i]);
+
+    /* Load previous sample */
+    float re2 = crealf(x[i - 1]);
+    float im2 = cimagf(x[i - 1]);
+
+    float pow = sqrtf((re1 * re1 + im1 * im1) * (re2 * re2 + im2 * im2));
+    sum_sin += (re1 * im2 - re2 * im1) / pow;
+  }
+  return asinf(sum_sin / (float)(len - 1)) / (2.0f * (float)M_PI);
+}