According to 3GPP TS 05.02, section 5.2.7, there are three
synch. sequences for Access Bursts:
- TS0: GSM, GMSK (default),
- TS1: EGPRS, 8-PSK,
- TS2: EGPRS, GMSK.
Let's prepare everythyng to be able to detect all TS0-3 synch.
sequences, but keep detection of both TS1 and TS2 disabled
until the corresponding VTY option is introduced.
Change-Id: I838c21db29c54f1924dd478c2b34b46b70aab2cd
Related: OS#3054
Setup correlator and detection process similar to the GMSK
receiver chain. Require 4 SPS sampling on both Rx and Tx paths
as 1 SPS sampling adds too much distoration for 8-PSK recovery.
Core receiver operations still run at 1 SPS with the exception
of fractional delay filtering, which runs at the higher rate.
Perform linear equalization to handle the Gaussian pulse
induced ISI. The fixed impulse response used for equalizer tap
calculation consists of combined EDGE pulse shape filter and
effects of the downsampling filter. Note that the non-adaptive
equalizer corrects for modulation induced band limiting and
does not account for or compensate for fading channel effects.
Signed-off-by: Tom Tsou <tom.tsou@ettus.com>
Pau Espin
Vadim Yanitskiy