Osmocom Base Transceiver Station (BTS)
https://osmocom.org/projects/osmobts
Harald Welte
a4bd813081
The so-called "RTP mode" of the DSP contains a bug on all firmware versions < 5.3.3 which causes the bit-order within each of the non-aligned codec parameters to be wrong. Introduce a function originally written by Sylvain Munaut during 32C3 in http://git.osmocom.org/openbsc/commit/?h=sylvain/32c3_codec&id=5b4a16bbe93a7b1ace65cc23d6cce56ecf4f1275 to bring the bits into [the correct] order. This has never been seen in a "pure sysmoBTS" setup, as all BTSs would use the same (wrong) bit-ordering and thus interoperate. This patch now checks for an affected DSP firmware version and then jumbles (old DSP firmware version) or does nothing (new DSP firmware version). Change-Id: Ia0eee4f514fb8fd81c052bb44a4facba898d6afb Closes: SYS#2452 |
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README
Repository forw the Osmocom BTS implementation. This code implementes the Layer 2 and higher of a more or less conventional GSM BTS (Base Transceiver Station) - however, using an Abis/IP interface, rather than the old-fashioned E1/T1. Specifically, this includes * BTS-Side implementation of TS 08.58 (RSL) and TS 12.21 (OML) * BTS-Side implementation of LAPDm (using libosmocore/libosmogsm) * A somewhat separated interface between those higher layer parts and the Layer1 interface. Right now, only one hardware and Layer1 are supported: The sysmocom sysmoBTS. There is some experimental and way incomplete code to use a couple of OsmocomBB phones and run them in the BTS. However, the required code for the Calypso DSP code have not been written yet. This would still require a lot of work. Some additional work is being done in using some parts of the OpenBTS L1FEC and glue it against omso-bts. This code is called osmo-trx and requires the jolly/trx branch of this repository. == Known Limitations == As of August 20, 2015, the following known limitations exist in this implementation: === Common Core === * No Extended BCCH support * System Information limited to 1,2,2bis,2ter,2quater,3,4,5,6,9,13 * No RATSCCH in AMR * No OML (TS 12.21) alarms yet (temperature, ...) * Only single-TRX BTS at this point * Will reject TS 12.21 STARTING TIME in SET BTS ATTR / SET CHAN ATTR * No support for frequency hopping * No reporting of interference levels as part of TS 08.58 RF RES IND * No error reporting in case PAGING COMMAND fails due to queue overflow * No use of TS 08.58 BS Power and MS Power parameters * No support of TS 08.58 MultiRate Control * No support of TS 08.58 Supported Codec Types * No support of Bter frame / ENHANCED MEASUREMENT REPORT === osmo-bts-sysmo === * No CSD / ECSD support (not planned) * GSM-R frequency band supported, but no NCH/ASCI/SoLSA * All timeslots on one TRX have to use same training sequence (TSC) * No multi-TRX support yet, though hardware+L1 support stacking * Makes no use of 12.21 Intave Parameters and Interference Level Boundaries * Doesn't yet include MAC address in Abis/IP Identity message * MphConfig.CNF can be returned to the wrong callback. E.g. with Tx Power and ciphering. The dispatch should take a look at the hLayer3.