60 lines
2.4 KiB
Plaintext
60 lines
2.4 KiB
Plaintext
Repository for new the Osmocom BTS implementation.
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This code implementes the Layer 2 and higher of a more or less
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conventional GSM BTS (Base Transceiver Station) - however, using an
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Abis/IP interface, rather than the old-fashioned E1/T1.
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Specificallt, this includes
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* BTS-Side implementation of TS 08.58 (RSL) and TS 12.21 (OML)
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* BTS-Side implementation of LAPDm (using libosmocore/libosmogsm)
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* A somewhat separated interface between those higher layer parts
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and the Layer1 interface.
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Right now, only one hardware and Layer1 are supported: The sysmocom
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sysmoBTS.
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There is some experimental and way incomplete code to use a couple of
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OsmocomBB phones and run them in the BTS. However, the required code
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for the Calypso DSP code have not been written yet. This would still
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require a lot of work.
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Some additional work is being done in using some parts of the OpenBTS
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L1FEC and glue it against omso-bts. However, this is also still in an
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early, experimental stage.
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== Known Limitations ==
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As of June 3, 2012, the following known limitations exist in this
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implementation:
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=== Common Core ===
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* No Extended BCCH support
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* System Information limited to 1,2,2bis,2ter,2quater,3,4,5,6,9,13
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* No RATSCCH in AMR
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* No OML (TS 12.21) alarms yet (temperature, ...)
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* Only single-TRX BTS at this point
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* Will reject TS 12.21 STARTING TIME in SET BTS ATTR / SET CHAN ATTR
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* No support for frequency hopping
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* No reporting of interference levels as part of TS 08.58 RF RES IND
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* No error reporting in case PAGING COMMAND fails due to queue overflow
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* No hand-over support (planned)
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* No use of TS 08.58 BS Power and MS Power parameters
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* No support of TS 08.58 MultiRate Control
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* No support of TS 08.58 Supported Codec Types
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* No support of Bter frame / ENHANCED MEASUREMENT REPORT
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=== osmo-bts-sysmo ===
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* No CSD / ECSD support (not planned)
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* No GPRS/EDGE support (planned)
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* GSM-R frequency band supported, but no NCH/ASCI/SoLSA
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* All timeslots on one TRX have to use same training sequence (TSC)
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* No multi-TRX support yet, though hardware+L1 support stacking
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* Makes no use of 12.21 Intave Parameters and Interference
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Level Boundaries
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* Makes no use of TS 12.21 T3105
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* Doesn't yet include MAC address in Abis/IP Identity message
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* MphConfig.CNF can be returned to the wrong callback. E.g. with Tx Power
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and ciphering. The dispatch should take a look at the hLayer3.
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