On Wed, Jul 6, 2016 at 10:19 PM, Alexander Chemeris alexander.chemeris@gmail.com wrote:
On Jul 7, 2016 7:58 AM, "Tom Tsou" tom@tsou.cc wrote:
The full BER calculation takes the re-coded and re-punctured sequence (performed after decoding and CRC verification)
Why after CRC?
Assume that we lower the detection threshold in the TRX and allow the OsmoBTS to perform most of the burst gating based on the CRC. If we calculate BER before the CRC, then the BER will be computed mostly on garbage data.
A close and simple approximation to the full BER calculation treats all zero valued soft bits as punctured bits and removes them from the calculation.
I think this is a reasonable approach to make the current BER measurement sane.
Why do you think re-puncturing is not a good approach - because of the added CPU load?
Yes, there is overhead. But, more simply, re-puncturing doesn't gain very much. If we increase the accuracy of our BER calculation by some fraction of a percent, will that really improve UE performance?
-TT