From 3c56a7edc5aec64d7735e1a6256a5493429d04ba Mon Sep 17 00:00:00 2001
From: Florian Kaltenberger <florian.kaltenberger@eurecom.fr>
Date: Wed, 7 Jun 2017 18:11:44 +0200
Subject: [PATCH] a new proposal for the dlsch_channel_level function
---
.../PHY/LTE_TRANSPORT/dlsch_demodulation.c | 34 +++++++++++--------
1 file changed, 20 insertions(+), 14 deletions(-)
diff --git a/openair1/PHY/LTE_TRANSPORT/dlsch_demodulation.c b/openair1/PHY/LTE_TRANSPORT/dlsch_demodulation.c
index 1450209c260..e6d2ec301f3 100644
--- a/openair1/PHY/LTE_TRANSPORT/dlsch_demodulation.c
+++ b/openair1/PHY/LTE_TRANSPORT/dlsch_demodulation.c
@@ -3377,7 +3377,7 @@ void dlsch_channel_level(int **dl_ch_estimates_ext,
short rb;
unsigned char aatx,aarx,nre=12,symbol_mod;
- __m128i *dl_ch128, avg128D, coeff128;
+ __m128i *dl_ch128, avg128D;
symbol_mod = (symbol>=(7-frame_parms->Ncp)) ? symbol-(7-frame_parms->Ncp) : symbol;
@@ -3388,11 +3388,12 @@ void dlsch_channel_level(int **dl_ch_estimates_ext,
else
nre=12;
- double one_over_nb_re = 0.0;
- one_over_nb_re = 1/((double)(nb_rb*nre));
- int16_t one_over_nb_re_q1_15 = (int16_t)(one_over_nb_re * (double)(1<<15) );
- coeff128 = _mm_set_epi16(one_over_nb_re_q1_15,one_over_nb_re_q1_15,one_over_nb_re_q1_15,one_over_nb_re_q1_15,
- one_over_nb_re_q1_15,one_over_nb_re_q1_15,one_over_nb_re_q1_15,one_over_nb_re_q1_15);
+ //nb_rb*nre = y * 2^x
+ int16_t x = log2_approx(nb_rb*nre)-1;
+ //int16_t one_over_y_q15 = (int16_t)((1<<((int32_t)x+15))/((int32_t)nb_rb*(int32_t)nre));
+ float y = (float)(nb_rb*nre)/(float)(1<<x);
+ //printf("1/(nb_rb*nre) = 1/%d = %d*2^(-15) * 2^(-%d)\n",nb_rb*nre,one_over_y_q15,x);
+ printf("nb_rb*nre = %d = %f * 2^(%d)\n",nb_rb*nre,y,x);
for (aatx=0; aatx<frame_parms->nb_antenna_ports_eNB; aatx++)
for (aarx=0; aarx<frame_parms->nb_antennas_rx; aarx++) {
@@ -3405,14 +3406,18 @@ void dlsch_channel_level(int **dl_ch_estimates_ext,
for (rb=0;rb<nb_rb;rb++) {
// printf("rb %d : ",rb);
// print_shorts("ch",&dl_ch128[0]);
- avg128D = _mm_add_epi32(avg128D,_mm_madd_epi16(dl_ch128[0],_mm_srai_epi16(_mm_mulhi_epi16(dl_ch128[0], coeff128),15)));
- avg128D = _mm_add_epi32(avg128D,_mm_madd_epi16(dl_ch128[1],_mm_srai_epi16(_mm_mulhi_epi16(dl_ch128[1], coeff128),15)));
+ avg128D = _mm_add_epi32(avg128D,_mm_srai_epi16(_mm_madd_epi16(dl_ch128[0],dl_ch128[0]),x));
+ avg128D = _mm_add_epi32(avg128D,_mm_srai_epi16(_mm_madd_epi16(dl_ch128[1],dl_ch128[1]),x));
+
+ //avg128D = _mm_add_epi32(avg128D,_mm_madd_epi16(dl_ch128[0],_mm_srai_epi16(_mm_mulhi_epi16(dl_ch128[0], coeff128),15)));
+ //avg128D = _mm_add_epi32(avg128D,_mm_madd_epi16(dl_ch128[1],_mm_srai_epi16(_mm_mulhi_epi16(dl_ch128[1], coeff128),15)));
if (((symbol_mod == 0) || (symbol_mod == (frame_parms->Ncp-1)))&&(frame_parms->mode1_flag==0)) {
dl_ch128+=2;
}
else {
- avg128D = _mm_add_epi32(avg128D,_mm_madd_epi16(dl_ch128[2],_mm_srai_epi16(_mm_mulhi_epi16(dl_ch128[2], coeff128),15)));
+ avg128D = _mm_add_epi32(avg128D,_mm_srai_epi16(_mm_madd_epi16(dl_ch128[2],dl_ch128[2]),x));
+ //avg128D = _mm_add_epi32(avg128D,_mm_madd_epi16(dl_ch128[2],_mm_srai_epi16(_mm_mulhi_epi16(dl_ch128[2], coeff128),15)));
dl_ch128+=3;
}
/*
@@ -3424,11 +3429,12 @@ void dlsch_channel_level(int **dl_ch_estimates_ext,
*/
}
- avg[(aatx<<1)+aarx] =(((int32_t*)&avg128D)[0] +
- ((int32_t*)&avg128D)[1] +
- ((int32_t*)&avg128D)[2] +
- ((int32_t*)&avg128D)[3]);
- // printf("Channel level : %d\n",avg[(aatx<<1)+aarx]);
+ avg[(aatx<<1)+aarx] = (((int32_t*)&avg128D)[0] +
+ ((int32_t*)&avg128D)[1] +
+ ((int32_t*)&avg128D)[2] +
+ ((int32_t*)&avg128D)[3]);
+ avg[(aatx<<1)+aarx] = (int32_t) ((float) avg[(aatx<<1)+aarx]/y);
+ printf("Channel level : %d\n",avg[(aatx<<1)+aarx]);
}
_mm_empty();
--
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