osmo-trx rx gain question

[Harald Welte]

Hi Tom,

In osmo-bts, we have the notion of a "phy link" and a "phy instance".

A PHY Link defines some kind of logical or physical interfae to a given
PHY layer implementation.  This can be some kind of shared memory
device (sysmobts, litecell15), or a ethernet device (octbts).

The PHY Instance is a logical instance serving one ARFCN within the PHY
Link.

AFAIR, for osmo-bts-trx, we moved the attenuation/gain parameters at
some point into the "instance" so that there can be separate parameters
for each of the two TRX.

If I understand you correctly, osmo-trx has two modes of multi-trx
operation:

a) two soft ARFCN in one RF dac/adc-rx/tx chain in the SDR
b) two sets of single-TRX, each on a separate dac/adc-rx/tx chain in the SDR

Correct?

In that case, the problem is that 'a' and 'b' would differ in terms of
where the parameters should be put.  In 'a' it should be global
parameters for the entire 'PHY Link', in 'b' it shold be per 'PHY
Instance'.

The only obvious logical way to resolve this would be to move the
parameters to the 'PHY Link'.  'a' would then have one PHY link with two
PHY instances (shared params), and 'b' would have two PHY links which
one instance each (separate params).

The question is then how the separate TRX are exposed on the
UDP-protocol between osmo-trx and osmo-bts-trx.  I haven't yet looked at
that part of the code [or forgot, sorry].

Regards,
	Harald
-- 
- Harald Welte <laforge at gnumonks.org>           http://laforge.gnumonks.org/
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