conversion of some sse4 code to avx2 for turbo encoder. No noticeable...

conversion of some sse4 code to avx2 for turbo encoder.  No noticeable improvement (output expansion for encoder doesn't benefit much because of unpack instruction difference on AVX2.

maxh adjustement in dlsch_demodulation (to be checked further for other mcs)

exit criterion in dlsim to allow estimation of lower BLER.