commit e90c24c8d52349094e7f6dc11b9ea86a1f611b00
author Tom Tsou <tom.tsou@ettus.com> Tue Jun 21 16:14:39 2016 -0700
committer Tom Tsou <tom.tsou@ettus.com> Tue Jun 21 16:19:54 2016 -0700
tree 5034e1b01fa9666798c8849a86ffa429c7f31141
parent 3b093bb13ba04f03f1f078b986524eacb7d4a3f1

sigproc: Expand RACH, TSC, and EDGE correlation windows

Slightly widen the search range to accommodate timing jitter
on certain classes of devices. The expanded range minimizes
the possibility of missing bursts that arrive too early or
too late due to timing error.

Signed-off-by: Tom Tsou <tom.tsou@ettus.com>

Transceiver52M/sigProcLib.cpp

diff --git a/Transceiver52M/sigProcLib.cpp b/Transceiver52M/sigProcLib.cpp
index 049bc5a..434bbaf 100644
--- a/Transceiver52M/sigProcLib.cpp
+++ b/Transceiver52M/sigProcLib.cpp
@@ -1858,8 +1858,8 @@
  *
  * Correlation window parameters:
  *   target: Tail bits + RACH length (reduced from 41 to a multiple of 4)
- *   head: Search 4 symbols before target
- *   tail: Search 4 symbols + maximum expected delay
+ *   head: Search 8 symbols before target
+ *   tail: Search 8 symbols + maximum expected delay
  */
 int detectRACHBurst(signalVector &rxBurst,
             float thresh,
@@ -1872,8 +1872,8 @@
   CorrelationSequence *sync;
 
   target = 8 + 40;
-  head = 4;
-  tail = 4 + maxTOA;
+  head = 8;
+  tail = 8 + maxTOA;
   sync = gRACHSequence;
 
   rc = detectGeneralBurst(rxBurst, thresh, sps, amp, toa,
@@ -1887,8 +1887,8 @@
  *
  * Correlation window parameters:
  *   target: Tail + data + mid-midamble + 1/2 remaining midamblebits
- *   head: Search 4 symbols before target
- *   tail: Search 4 symbols + maximum expected delay
+ *   head: Search 6 symbols before target
+ *   tail: Search 6 symbols + maximum expected delay
  */
 int analyzeTrafficBurst(signalVector &rxBurst, unsigned tsc, float thresh,
                         int sps, complex &amp, float &toa, unsigned max_toa)
@@ -1900,8 +1900,8 @@
     return -SIGERR_UNSUPPORTED;
 
   target = 3 + 58 + 16 + 5;
-  head = 4;
-  tail = 4 + max_toa;
+  head = 6;
+  tail = 6 + max_toa;
   sync = gMidambles[tsc];
 
   rc = detectGeneralBurst(rxBurst, thresh, sps, amp, toa,
@@ -1919,8 +1919,8 @@
     return -SIGERR_UNSUPPORTED;
 
   target = 3 + 58 + 16 + 5;
-  head = 5;
-  tail = 5 + max_toa;
+  head = 6;
+  tail = 6 + max_toa;
   sync = gEdgeMidambles[tsc];
 
   rc = detectGeneralBurst(rxBurst, thresh, sps, amp, toa,