osmo-bts - Osmocom BTS Implementation ==================================== This repository contains a C-language implementation of a GSM Base Transceiver Station (BTS). It is part of the [Osmocom](https://osmocom.org/) Open Source Mobile Communications project. This code implements 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. Several kinds of BTS hardware are supported: * sysmocom sysmoBTS * Octasic octphy * Nutaq litecell 1.5 * software-defined radio based osmo-bts-trx (e.g. USRP B210, UmTRX) Homepage -------- The official homepage of the project is https://osmocom.org/projects/osmobts/wiki GIT Repository -------------- You can clone from the official osmo-bts.git repository using git clone git://git.osmocom.org/osmo-bts.git There is a cgit interface at http://git.osmocom.org/osmo-bts/ Documentation ------------- We provide a [User Manual](http://ftp.osmocom.org/docs/latest/osmobts-usermanual.pdf) as well as a [VTY Reference Manual](http://ftp.osmocom.org/docs/latest/osmobsc-vty-reference.pdf) and a [Abis refrence MAnual](http://ftp.osmocom.org/docs/latest/osmobts-abis.pdf) describing the OsmoBTS specific A-bis dialect. Mailing List ------------ Discussions related to osmo-bts are happening on the openbsc@lists.osmocom.org mailing list, please see https://lists.osmocom.org/mailman/listinfo/openbsc for subscription options and the list archive. Please observe the [Osmocom Mailing List Rules](https://osmocom.org/projects/cellular-infrastructure/wiki/Mailing_List_Rules) when posting. Contributing ------------ Our coding standards are described at https://osmocom.org/projects/cellular-infrastructure/wiki/Coding_standards We us a gerrit based patch submission/review process for managing contributions. Please see https://osmocom.org/projects/cellular-infrastructure/wiki/Gerrit for more details The current patch queue for osmo-bts can be seen at https://gerrit.osmocom.org/#/q/project:osmo-bts+status:open Known Limitations ================= As of March 17, 2017, 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 * 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 * 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. osmo-bts-octphy --------------- * No support of EFR, HR voice codec (lack of PHY support?) * No re-transmission of PHY primitives in case of time-out * Link Quality / Measurement processing incomplete * impossible to modify encryption parameters using RSL MODE MODIFY * no clear indication of nominal transmit power, various power related computations are likely off * no OML attribute validation during bts_model_check_oml() osmo-bts-trx ------------ * TCH/F_PDCH cannel not working as voice (https://osmocom.org/issues/1865) * No BER value delivered to OsmoPCU (https://osmocom.org/issues/1855) * No 11bit RACH support (https://osmocom.org/issues/1854)