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OpenAir2 Core Development

This section covers status and roadmaps for openair2 development, currently focusing on OpenAirLTE branch.

Reference Openair2 Protocol Stack

Figure below shows the protocol stack of the reference OpenAirInterface 4G platform. The purpose is to develop an open-source access layer implementation of a subset of LTE Rel. 8/9 on the top of the Openair1, which will be part of OpenAirInterface software/hardware platforms.


Current status and features

eNB MAC implementation (3GPP 36-311)

  • Schedulers (basic weighted round-robin, BSR and SR support for UL, no power-headroom support for the moment).
  • DCI generation
  • full RA procedures, RNTI management
  • most PDU formats (compliant)
  • RLC interface (AM, UM)
  • RRC interface for SI and CCCH
UE MAC implementation (3GPP 36-311)
  • most PDU formats (compliant) : timing advance CE, contention resolution CE, BSR CE
  • RLC interface (AM,UM)
  • RRC interface for SI and CCCH
RLC implementation (3GPP 36-321)
  • Rel 9 UM/TM/AM
RRC implementations
  • RRC Lite - provides basic connection management and measurement reporting. Full ASN.1 encoding/decoding (with asn1c), default SRB/DRB configurations.
  • RRC - Esterel-based state-machine implementation (timers), no ASN.1 messages, connection management for IPv6-based CN.
PDCP implementation
  • Black-box interconnection between Linux IP netdevice and RLC user-plane traffic. Header is managed, SRBs not managed.
  • no ROHC or security mechanisms currently
  • nasmesh - Linux netdevice with classification services to DRB, MPLS support (2.6.20 kernel only). Support for user-space access-stratum operation
  • nasdriver - Linux netdevice with classication services to DRB, RRC interface for connection management. Support only for kernel-space implementation of access-stratum (i.e. no user-space emulation)

Short-term Roadmap

Action Expected Date of Completion Status People Involved
MAC Scheduler architecture (generic MAC API) 6/12 Ongoing NN,CB
MAC control element implementation done done NN
MAC Random Access procedures done done NN+RK
Rel-9 RLC UM/TM implementation complete, testing UM with out-of-order TBs Ongoing LG
Rel-9 RLC AM done done LG
PDCP/nasmesh integration testing 6/12 Ongoing NN
Cellular RRC integration 3/12 Ongoing MW
Emulation Type 2 mode 2 ? Ongoing NN
RRC lite + MAC mobility support (handover) 5/12 Ongoing


RRC lite measurement reporting 5/12 Ongoing RK

Return to OpenAirRoadmaps

-- NavidNikaein - 05 Jan 2011

Topic attachments
I Attachment Action Size Date Who Comment
PNGpng oai_protocol_stack.png manage 49.3 K 09 Jan 2011 - 15:39 NavidNikaein  
PNGpng oai_ref_protocol_stack.png manage 41.3 K 10 Dec 2010 - 15:39 NavidNikaein  
Topic revision: r8 - 08 Mar 2012 - RaymondKnopp
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