From ce0f48d2b2cc54d4e68afa6cd7049645632e2fa9 Mon Sep 17 00:00:00 2001
From: luis_pereira87 <lpereira@allbesmart.pt>
Date: Fri, 7 Jun 2024 15:12:59 +0100
Subject: [PATCH] Add support for MIMO 2x2 with USRP B210 at 20 MHz BW and 3/4
 sampling rate

Tested with B210 and Quectel RM500Q-GL
---
 openair1/PHY/NR_TRANSPORT/nr_prach.c    | 6 ++++++
 openair1/PHY/NR_UE_TRANSPORT/nr_prach.c | 8 +++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/openair1/PHY/NR_TRANSPORT/nr_prach.c b/openair1/PHY/NR_TRANSPORT/nr_prach.c
index 4bf70acaa8..c9f645333b 100644
--- a/openair1/PHY/NR_TRANSPORT/nr_prach.c
+++ b/openair1/PHY/NR_TRANSPORT/nr_prach.c
@@ -316,6 +316,12 @@ void rx_nr_prach_ru(RU_t *ru,
     dftlen >>= 1;
     break;
 
+  case 23040:
+    // 20 MHz @ 23.04 Ms/s
+    Ncp = (Ncp * 3) / 4;
+    dftlen = (dftlen * 3) / 4;
+    break;
+
   case 30720:
     // 20, 25, 30 MHz @ 30.72 Ms/s
     break;
diff --git a/openair1/PHY/NR_UE_TRANSPORT/nr_prach.c b/openair1/PHY/NR_UE_TRANSPORT/nr_prach.c
index ea24f0a45c..471b2aee38 100644
--- a/openair1/PHY/NR_UE_TRANSPORT/nr_prach.c
+++ b/openair1/PHY/NR_UE_TRANSPORT/nr_prach.c
@@ -65,7 +65,7 @@ int32_t generate_nr_prach(PHY_VARS_NR_UE *ue, uint8_t gNB_id, int frame, uint8_t
   c16_t prach[(4688 + 4 * 24576) * 2] __attribute__((aligned(32))) = {0};
   int16_t prachF_tmp[(4688+4*24576)*4*2] __attribute__((aligned(32))) = {0};
 
-  int16_t Ncp = 0;
+  int Ncp = 0;
   int prach_start, prach_sequence_length, i, prach_len, dftlen, mu, kbar, K, n_ra_prb, k, prachStartSymbol, sample_offset_slot;
 
   fd_occasion             = 0;
@@ -332,6 +332,12 @@ int32_t generate_nr_prach(PHY_VARS_NR_UE *ue, uint8_t gNB_id, int frame, uint8_t
     dftlen >>= 1;
     break;
 
+  case 23040:
+    // 20 MHz @ 23.04 Ms/s
+    Ncp = (Ncp * 3) / 4;
+    dftlen = (dftlen * 3) / 4;
+    break;
+
   case 30720:
     // 20, 25, 30 MHz @ 30.72 Ms/s
     break;