assignment command / status of RR
Andreas.Eversberg at versatel.de
Mon Aug 16 07:55:39 UTC 2010
as you can see in the git log, i checked in the "ASSIGNMENT COMMAND"
processing. it modifies timeslot, subslot, and hopping sequence. this is
required when the network assigns an SDCCH before the actual TCH is
allocated: after receiving the "ASSIGNMENT COMMAND", the layer2 is
release locally (without sending anything), the dedicated mode is
released and established with a new parameters (e.g. TCH/F), and the
layer2 is established again, finally the "ASSIGNMENT COMPLETE" is sent
to the network. this process is incomplete, but it should work in most
cases. (no "starting time" processing).
in my local copy of the git, i already completed the assignment process.
additionally "FREQUENCY REDEFINITION" is completed, "IMMEDIATE
ASSIGNMENT" supports "starting time", MDL-error processing is added, and
"HANDOVER COMMAND" parsing is done. the handover process is not
completed, because it depends on unimplemented layer1 features, like
RX-only channels or "4 successive HANDOVER ACCESS bursts on DCCH".
except the handover process, the RR protocol for basic phone calls is
before i can check it in, it depends on two things. first, there are
additional messages to be defined in osmocore:
"[osmocore] Adding handover and frequency redefiniton message headers"
second, it depends on "starting time" support for layer1:
it adds a L1CTL message to store modified frequency allocations (ma,
ma_len, HSN, MAIO, TSC) for hopping and a "starting time". this starting
time is the frame number at which the modified frequencies are used. if
the frame number lies in the past, the new modified frequencies are used
after the L1CTL message is received.
sylvain already noted, that the event of "starting time" should be
triggered by the scheduler. since i don't know how the scheduler exactly
works, i would ask someone to change my patch. note that the dedicated
mode can be released before the "starting time" elapses.
as soon as both things above are in the master branch, i will commit my
latest work on RR.
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