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Revision 10 (laforge, 02/19/2016 10:48 PM) → Revision 11/33 (laforge, 02/21/2016 02:51 PM)

 h1. [[OsmoBTS]] 


 [[OsmoBTS]] is a software implementation of Layer2/3 of a BTS. It implements the follwing protocols/interfaces: 
 * LAPDm (GSM 04.06) 
 * RTP 
 * A-bis/IP in IPA multiplex 
 * OML (GSM TS 12.21) 
 * RSL (GSM TS 08.58) 

 [[OsmoBTS]] is building up on work done previosuly for [[OpenBSC]] (RSL, OML, RTP) and "OsmocomBB": (LAPDm).    The Abis/IP protocol staking is inspired by ip.access A-bis/IP, sometimes called IPA multiplex. 


 h2. OsmoBTS in the Osmocom architecture 

 digraph G { 
     rankdir = LR; 
     OsmoTRX -> OsmoBTS [label="bursts over UDP"]; 
     sysmoPHY -> OsmoBTS [label="/dev/msgq/"]; 
     octPHY -> OsmoBTS [label="Raw Ethernet"]; 
     OsmoBTS -> OsmoNITB [label="Abis/IP"]; 
     OsmoBTS -> OsmoPCU [label="pcu_sock"]; 
     OsmoPCU -> OsmoSGSN [label="Gb/IP"]; 
     OsmoBTS [color=red]; 

 h2. Backends / Hardware support 


 [[OsmoBTS]] is modular and has support for multiple back-ends.    A back-end talks to a specific L1/PHY implementation of the respective BTS hardware. Based on this architecture, it should be relatively easy to add a new back-end to support so-far unsupported GSM PHY/L1 and associated hardware. 

 So far [[OsmoBTS]] has been integrated with several different L1/PHY and hardware systems. The backends are: 
 * osmo-bts-sysmo 
 ** Multiple indoor and outdoor BTS products    called "sysmoBTS": which is sold by "sysmocom": 
 * osmo-bts-trx 
 ** Wideband SDR transceiver hardware supported by [[OpenBTS]] transceiver or [OsmoTRX] PHY layer software, including the [[UmTRX]], the USRP family, etc. 
 ** Multiple indoor and outdoor "fairwaves": BTSs, like [[UmDESK]] and [[UmSITE]] 
 * osmo-bts-bb 
 ** A pretty crazy experimental BTS hardware based on two [[OsmocomBB]] phones had originally been supported, but needs to be re-integrated with core code changes. 


 h2. Status 


 The source code includes a file with current status information 


 h2. GPRS support 


 osmo-bts has recently been extended with a socket interface towards [[osmo-pcu]]. This adds GPRS (and later EDGE) support to it. 


 h2. Source code 


 The source code is available from (module osmo-bts). 

 Public read-only access is available via 
  git clone git:// 
 You can browse it via cgit: 


 h2. Authors / Credits 


 [[OsmoBTS]] was originally developed in 2011 by Andreas Eversberg and Harald Welte.   

 Today it is mostly maintained by Harald Welte and Holger Freyther at sysmocom.    Exception is the osmo-bts-trx back-end which is maintained by Fairwaves.
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