Project

General

Profile

Actions

OsmoPCU » History » Revision 19

« Previous | Revision 19/32 (diff) | Next »
laforge, 03/06/2016 05:23 AM
fix more links


osmo-pcu

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 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 OsmoSGSN 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.

Manuals

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/

Mailing List

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

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

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

Authors / Credits

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

Today it is maintaned by Jacob Erlbeck at sysmocom.

Files (3)
osmo-pcu-0.1.tar.bz2 osmo-pcu-0.1.tar.bz2 350 KB release version 0.1 of osmo-pcu laforge, 01/17/2013 11:37 AM
pcu-edge-osmocom-org.pcap.bz2 pcu-edge-osmocom-org.pcap.bz2 243 KB First internet access through osmo-pcu using EDGE , 02/04/2016 05:30 PM
egprs-gsmtap-dissector.patch egprs-gsmtap-dissector.patch 6.48 KB WIP patch to add EDGE decoding for RLC frames contained in GSMTAP. , 02/04/2016 05:50 PM

Updated by laforge about 8 years ago · 19 revisions

Add picture from clipboard (Maximum size: 48.8 MB)