RF power problems with current master of osmo-trx

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Tom Tsou tom at tsou.cc
Sat Jan 25 18:58:06 UTC 2014


On Sat, Jan 25, 2014 at 2:57 AM, Andreas Eversberg <andreas at eversberg.eu> wrote:
> so when i stop sending the bursts, the filler table will continue to
> transmit bursts. do i understand it correctly: if i send a single idle burst
> (frame??) after sending bursts, the filler table is disabled until new
> bursts are sent?

Sorry, I misspoke about disabling transmission. The filler table
resends the last burst in the multiframe, so the idle burst is usually
just a dummy burst, which does not actually stop physical
transmission. To fully turn off the downlink signal on a particular
slot requires disabling the slot by the channel combination.

That said, I agree with Alexander that the retransmission portion of
the filler table should be turned off because the behavior is
incorrect. With a few exceptions (e.g. FCCH), bursts should *not* be
retransmitted at L1 and doing so generates an invalid signal.

Note that the filler table cannot be completely disabled because it is
part of the real-time loop that drives the device I/O. If the upper
layer does not send a burst for a particular slot, or that burst
arrives late (stale burst), something still must be transmitted.
Currently, in that case, the burst comes from the filler table if the
slot is active or zeros if the slot is turned off. Again, I do not
think the current implementation is entirely correct, but that depends
on expectations of the upper layers.

  -TT




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