Osmocom Packet control Unit (PCU): Network-side GPRS (RLC/MAC); BTS- or BSC-colocated
https://osmocom.org/projects/osmopcu
Philipp Maier
1275a3f91a
The implementation of the method rcv_rach() in class BTS, restores the absolute frame number of the incoming RACH-Request by using the relative frame number (RFn = Fn mod 42432) from the rach request and the already known internal absolute frame number m_cur_fn, which is continusly updated by the CCU interface. In some rare cases, a RACH request might be received by the BTS, a very short time before the frame number wraps in its 42432. Depending on the PCU location, RACH request might be received by the BSC, which forwards it to the PCU. It is then likely that, while the RACH request is being forwarded to the PCU, the PCU internal absolute frame number wraps before the RACH can be processed. The relative frame number from the rach request would then be interpreted as if it were received after the wrapping of the internal frame number modulos. This commit adds logic to detect and resolve this race condition. Also a unit test is added to check some cornercases. Change-Id: I74f00c11e5739d49f370ce6c357149e81d9aa759 |
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| .gitignore | ||
| .gitreview | ||
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| Makefile.am | ||
| README | ||
| TODO | ||
| configure.ac | ||
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| osmoappdesc.py | ||
README
This is an implementation of Packet Control Unit (PCU) according to TS 04.60 The PCU is part of BSS, so it connects directly to SGSN. == Current limitations == * No PFC support * No fixed allocation support * No extended dynamic allocation support * No unacknowledged mode operation * Only single slot assignment on uplink direction * No half-duplex class support (only semi-duplex) * No handover support * No measurement support * No TA loop * No power loop * No CS loop * No EGPRS