diff options
| author | Thomas Tsou <tom@tsou.cc> | 2014-04-16 23:34:21 -0400 |
|---|---|---|
| committer | Thomas Tsou <tom@tsou.cc> | 2014-10-06 10:35:29 -0700 |
| commit | 98b1af896c3e16bec418af654dd8fc2212c85fc5 (patch) | |
| tree | c6e0a9eb6a34bfd9828956cba41018bcfdccf7c5 | |
| parent | 14bb9c923d8c967e8ce114a868923e9566be51e5 (diff) | |
Transceiver52M: Use multiple SCH correlation ranges
Setup two SCH detection ranges - full search and narrow search. Full
search correlates the full burst length to find for SCH detection.
Narrow uses a reduced search range, which is the same as that used for
RACH detection.
Narrow searching is enabled after the SCH is successfully decoded and
the MS is locked to the frame timing.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
| -rw-r--r-- | Transceiver52M/Transceiver.cpp | 7 | ||||
| -rw-r--r-- | Transceiver52M/sigProcLib.cpp | 17 | ||||
| -rw-r--r-- | Transceiver52M/sigProcLib.h | 7 |
3 files changed, 24 insertions, 7 deletions
diff --git a/Transceiver52M/Transceiver.cpp b/Transceiver52M/Transceiver.cpp index 60be8d2..05f3b16 100644 --- a/Transceiver52M/Transceiver.cpp +++ b/Transceiver52M/Transceiver.cpp @@ -391,10 +391,13 @@ bool Transceiver::detectSCH(TransceiverState *state, signalVector &burst, complex &, float &toa) { - int shift; + int shift, full;; float mag, threshold = 7.0; - if (!detectSCHBurst(burst, threshold, mSPSRx, &, &toa)) + full = (state->mode == TRX_MODE_MS_TRACK) ? + SCH_DETECT_NARROW : SCH_DETECT_FULL; + + if (!detectSCHBurst(burst, threshold, mSPSRx, &, &toa, full)) return false; std::cout << "SCH : Timing offset " << toa << " symbols" << std::endl; diff --git a/Transceiver52M/sigProcLib.cpp b/Transceiver52M/sigProcLib.cpp index 0db3a81..22ecf97 100644 --- a/Transceiver52M/sigProcLib.cpp +++ b/Transceiver52M/sigProcLib.cpp @@ -1497,7 +1497,7 @@ int detectSCHBurst(signalVector &burst, float thresh, int sps, complex *amp, - float *toa) + float *toa, int state) { int rc, start, target, head, tail, len; float _toa; @@ -1508,10 +1508,19 @@ int detectSCHBurst(signalVector &burst, if ((sps != 1) && (sps != 4)) return -1; - /* Search full length */ target = 3 + 39 + 64; - head = target - 1; - tail = 39 + 3 + 9; + + switch (state) { + case SCH_DETECT_NARROW: + head = 4; + tail = 4; + break; + case SCH_DETECT_FULL: + default: + head = target - 1; + tail = 39 + 3 + 9; + break; + } start = (target - head) * sps - 1; len = (head + tail) * sps; diff --git a/Transceiver52M/sigProcLib.h b/Transceiver52M/sigProcLib.h index 90b6852..6cdf7b6 100644 --- a/Transceiver52M/sigProcLib.h +++ b/Transceiver52M/sigProcLib.h @@ -188,11 +188,16 @@ int detectRACHBurst(signalVector &rxBurst, complex *amplitude, float* TOA); +enum { + SCH_DETECT_FULL, + SCH_DETECT_NARROW, +}; + int detectSCHBurst(signalVector &rxBurst, float detectThreshold, int sps, complex *amplitude, - float* TOA); + float* TOA, int state); /** Normal burst correlator, detector, channel estimator. |