OsmoPCU » History » Version 14
jerlbeck, 02/19/2016 10:48 PM
update information about the PCU
| 1 | 3 | laforge | [[PageOutline]] |
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| 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. |
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| 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 | 11 | laforge | [wiki:OsmoTRX]. |
| 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 | 13 | laforge | It has been tested with [wiki:osmo-sgsn] as well as an Ericsson SGSN so far. |
| 15 | 1 | laforge | |
| 16 | 14 | jerlbeck | osmo-pcu is now considered stable and already performing useful service for a number of users, but as one |
| 17 | 11 | laforge | of the more recent additions to the Osmocom family, there still is plenty of area for improvement. |
| 18 | 1 | laforge | |
| 19 | == Source Code == |
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| 20 | |||
| 21 | The source code is available from git://git.osmocom.org/osmo-pcu.git |
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| 22 | |||
| 23 | You can browse it online via http://cgit.osmocom.org/cgit/osmo-pcu/ |
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| 24 | 4 | ipse | |
| 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 |
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| 30 | 3 | laforge | |
| 31 | == Status == |
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| 32 | 5 | daniel | Information about testing is available here: [wiki:GPRS-testing] |
| 33 | 3 | laforge | |
| 34 | 1 | laforge | === Supported === |
| 35 | 14 | jerlbeck | * GPRS CS1 to CS4 with dynamic link/rate adaption |
| 36 | * Single-slot and multi-slot operation on downlink |
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| 37 | * Single-slot operation on uplink |
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| 38 | * Independent TFI/USF per PDCH in single-slot allocation mode |
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| 39 | * Automatic or fixed PDCH allocation algorithm selection |
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| 40 | * Delayed release of downlink TBF |
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| 41 | * Active queue management for downlink TBF (!CoDel) |
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| 42 | * Initial setting of timing advance based on RACH |
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| 43 | * BSSGP BVC flow control support |
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| 44 | 3 | laforge | |
| 45 | === Shortcomings / Limitations / Restrictions === |
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| 46 | 1 | laforge | |
| 47 | * Pure GPRS PCU, no EGPRS (EDGE) functionality (yet) |
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| 48 | 12 | laforge | * Timeslots have to be assigned dedicated as a PDCH, no dynamic PDCH/TCH switching |
| 49 | 7 | jolly | * No support for hand-over of any sort yet |
| 50 | * No support of processing measurement reports |
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| 51 | 14 | jerlbeck | * No timing advance loop, i.e. radial movement is limited |
| 52 | * No support for power control |
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| 53 | 1 | laforge | * No Packet Access Reject message on congestion, access is just ignored |
| 54 | * No PCCCH support |
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| 55 | * Only "Dynamic allocation RLC data block transfer" is supported |
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| 56 | * No network controlled measurement/cell reselection order supported |
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| 57 | 7 | jolly | * No PTCCH support |
| 58 | 14 | jerlbeck | * No support for Packet Flow Contexts (PFC) |
| 59 | * No support for MS or PFC flow control |
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| 60 | * No support for RLC unacknowledged mode operation |
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| 61 | * No support for MBMS |
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| 62 | 12 | laforge | |
| 63 | == Authors / Credits == |
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| 64 | |||
| 65 | osmo-pcu was originally developed by Ivan Kluchnikov and Andreas Everberg. |
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| 66 | |||
| 67 | Today it is maintaned by Holger Freyther and Jacob Erlbeck at sysmocom. |
