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OsmoPCU » History » Revision 17

Revision 16 (Anonymous, 02/19/2016 10:48 PM) → Revision 17/32 (laforge, 03/06/2016 05:22 AM)

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 h1. osmo-pcu 

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 A PCU (Packet Control Unit) is one of the two GPRS elements in the BSS.    It implements the RLC and MAC layers of the GPRS 
 Um (radio) interface on the MS-facing side, as well as the Gb Interface (NS,BSSGP) on the SGSN-facing side. 

 osmo-pcu is the Osmocom implementation of this PCU functionality. 

 It implements a custom L1 interface that can be used with [[OsmoBTS]] (specifically its 
 "sysmoBTS":http://www.sysmocom.de/products/sysmobts back-end), and also with 
 [[OsmoTRX]]. 

 Towards the SGSN, the BSSGP and NS protocols are implemented over UDP/IP, sometimes called "NS over IP".  
 It has been tested with [[osmo-sgsn]] as well as an Ericsson SGSN so far. 

 osmo-pcu is now considered stable and already performing useful service for a number of users, but as one 
 of the more recent additions to the Osmocom family, there still is plenty of area for improvement. 

 


 h2. Manuals 

 * User Manual: http://ftp.osmocom.org/docs/latest/osmopcu-usermanual.pdf 
 * VTY Reference: http://ftp.osmocom.org/docs/latest/osmopcu-vty-reference.pdf 


 h2. Source Code 

 


 The source code is available from git://git.osmocom.org/osmo-pcu.git 

 You can browse it online via http://cgit.osmocom.org/cgit/osmo-pcu/ 


 



 h2. Mailing List 

 


 There is a mailing list for (development) discussion regarding the PCU: osmocom-net-gprs@lists.osmocom.org 
 You can subscribe to it (or manage your subscription) at http://lists.osmocom.org/cgi-bin/mailman/listinfo/osmocom-net-gprs 


 


 h2. Status 

 

 Information about testing is available here: [[GPRS-testing]] 


 


 h3. Supported 

 

 * GPRS CS1 to CS4 with dynamic link/rate adaption 
 * EDGE MCS1-MCS9 with dynamic link/rate adaption 
 * Single-slot and multi-slot operation on downlink 
 * Single-slot operation on uplink 
 * Independent TFI/USF per PDCH in single-slot allocation mode 
 * Automatic or fixed PDCH allocation algorithm selection 
 * Delayed release of downlink TBF 
 * Active queue management for downlink TBF (!CoDel) 
 * Initial setting of timing advance based on RACH 
 * BSSGP BVC flow control support 


 


 h3. Shortcomings / Limitations / Restrictions 


 


 * No GPRS/EGPRS mixed mode (yet) 
 * Timeslots have to be assigned dedicated as a PDCH, no dynamic PDCH/TCH switching 
 * No support for hand-over of any sort yet 
 * No support of processing measurement reports 
 * No timing advance loop, i.e. radial movement is limited 
 * No support for power control 
 * No Packet Access Reject message on congestion, access is just ignored 
 * No PCCCH support 
 * Only "Dynamic allocation RLC data block transfer" is supported 
 * No network controlled measurement/cell reselection order supported 
 * No PTCCH support 
 * No support for Packet Flow Contexts (PFC) 
 * No support for MS or PFC flow control 
 * No support for RLC unacknowledged mode operation 
 * No support for MBMS 


 


 h2. Authors / Credits 


 


 osmo-pcu was originally developed by Ivan Kluchnikov and Andreas Everberg. 

 Today it is maintaned by Jacob Erlbeck at sysmocom.
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