Change in osmocom-bb[master]: trx_toolkit/transceiver.py: add frequency hopping support

[Vadim Yanitskiy]

Hello laforge, Jenkins Builder, 

I'd like you to reexamine a change. Please visit

    https://gerrit.osmocom.org/c/osmocom-bb/+/18262

to look at the new patch set (#3).

Change subject: trx_toolkit/transceiver.py: add frequency hopping support
......................................................................

trx_toolkit/transceiver.py: add frequency hopping support

There are two ways to implement frequency hopping:

  a) The Transceiver is configured with the hopping parameters, in
     particular HSN, MAIO, and the list of ARFCNs (channels), so the
     actual Rx/Tx frequencies are changed by the Transceiver itself
     depending on the current TDMA frame number.

  b) The L1 maintains several Transceivers (two or more), so each
     instance is assigned one dedicated RF carrier frequency, and
     hence the number of available hopping frequencies is equal to
     the number of Transceivers. In this case, it's the task of
     the L1 to commutate bursts between Transceivers (frequencies).

Variant a) is commonly known as "synthesizer frequency hopping"
whereas b) is known as "baseband frequency hopping".

For the MS side, a) is preferred, because a phone usually has only
one Transceiver (per RAT). On the other hand, b) is more suitable
for the BTS side, because it's relatively easy to implement and
there is no technical limitation on the amount of Transceivers.

FakeTRX obviously does support b) since multi-TRX feature has been
implemented, as well as a) by resolving UL/DL frequencies using a
preconfigured (by the L1) set of the hopping parameters. The later
can be enabled using the SETFH control command:

  CMD SETFH <HSN> <MAIO> <RXF1> <TXF1> [... <RXFN> <TXFN>]

where <RXFN> and <TXFN> is a pair of Rx/Tx frequencies (in kHz)
corresponding to one ARFCN the Mobile Allocation. Note that the
channel list is expected to be sorted in ascending order.

NOTE: in the current implementation, mode a) applies to the whole
Transceiver and all its timeslots, so using in for the BTS side
does not make any sense (imagine BCCH hopping together with DCCH).

Change-Id: I587e4f5da67c7b7f28e010ed46b24622c31a3fdd
---
M src/target/trx_toolkit/burst_fwd.py
M src/target/trx_toolkit/ctrl_if.py
M src/target/trx_toolkit/ctrl_if_trx.py
M src/target/trx_toolkit/fake_pm.py
M src/target/trx_toolkit/transceiver.py
5 files changed, 140 insertions(+), 18 deletions(-)


  git pull ssh://gerrit.osmocom.org:29418/osmocom-bb refs/changes/62/18262/3
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Gerrit-Project: osmocom-bb
Gerrit-Branch: master
Gerrit-Change-Id: I587e4f5da67c7b7f28e010ed46b24622c31a3fdd
Gerrit-Change-Number: 18262
Gerrit-PatchSet: 3
Gerrit-Owner: Vadim Yanitskiy <axilirator at gmail.com>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: Vadim Yanitskiy <axilirator at gmail.com>
Gerrit-Reviewer: laforge <laforge at osmocom.org>
Gerrit-CC: pespin <pespin at sysmocom.de>
Gerrit-MessageType: newpatchset
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