Project

General

Profile

OsmoPCU » History » Version 10

Anonymous, 02/19/2016 10:48 PM

1 3 laforge
[[PageOutline]]
2 1 laforge
= osmo-pcu =
3
4 3 laforge
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
5
Um (radio) interface on the MS-facing side, as well as the Gb Interface (NS,BSSGP) on the SGSN-facing side.
6 1 laforge
7 3 laforge
osmo-pcu is the Osmocom implementation of this PCU functionality.
8
9 4 ipse
It implements a custom L1 interface that can be used with [wiki:OsmoBTS] (specifically its
10 1 laforge
[http://www.sysmocom.de/products/sysmobts sysmoBTS] back-end), and also with
11 3 laforge
an unofficial version of OpenBTS that is being created by Fairwaves.
12 1 laforge
13 3 laforge
Towards the SGSN, the BSSGP and NS protocols are implemented over UDP/IP, sometimes called "NS over IP". 
14
It has been tested with [wiki:OsmoSGSN] as well as an Ericsson SGSN so far.
15 1 laforge
16 3 laforge
osmo-pcu is not fully stable yet, but already performing useful service for a number of users.
17 1 laforge
18
== Source Code ==
19
20
The source code is available from git://git.osmocom.org/osmo-pcu.git
21
22
You can browse it online via http://cgit.osmocom.org/cgit/osmo-pcu/
23
24 4 ipse
The branch to be used with [wiki:OsmoBTS] and sysmoBTS is the 'jolly_merge' branch.
25 3 laforge
26 1 laforge
== Mailing List ==
27
28 10 laforge
There is a mailing list for (development) discussion regarding the PCU: osmocom-net-gprs@lists.osmocom.org
29
You can subscribe to it (or manage your subscription) at http://lists.osmocom.org/cgi-bin/mailman/listinfo/osmocom-net-gprs
30 3 laforge
31
== Status ==
32 5 daniel
Information about testing is available here: [wiki:GPRS-testing]
33 3 laforge
34
=== Supported ===
35
 * GPRS CS1 to CS4
36
 * single-slot and multi-slot operation on downlink
37
 * only single-slot operation on uplink
38
39
=== Shortcomings / Limitations / Restrictions ===
40
41
 * Pure GPRS PCU, no EGPRS (EDGE) functionality
42
 * Timeslots have to be assigned dedicated as a PDCH, no dynamic PDCH/TCH switching
43
 * No support for hand-over of any sort yet
44
 * No support of processing measurement reports
45
 * No timing advance loop, i.e. maximum cell radius 2-3 km
46
 * No dynamic link adaption for different coding schemes
47
 * No resource-dependent flow control
48 7 jolly
 * Single slot allocation algorithm only allocates the first available PDCH
49
 * Multi slot allocation algorithm
50
  - only allocates single uplink PDCH
51
  - limits allocation of type 1 mobile classes to 5 downlink PDCH
52
  - does not choose other uplink PDCH, if no USF is avaiable
53
 * No Packet Access Reject message on congestion, access is just ignored
54 8 jolly
 * No PCCCH support
55
 * Only "Dynamic allocation RLC data block transfer" is supported
56
 * No network controlled measurement/cell reselection order supported
57
 * No PTCCH support
Add picture from clipboard (Maximum size: 48.8 MB)