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OAI NB-IoT/eMTC Activities
Communication Systems Department
EURECOM
Unleashing the potential of open-source in the 5G arena
Summary
Overview for NB-IoT and eMTC
Current team, Objectives and progress – RRC work (Bologna/EURECOM) – Overview of NB-IoT PHY (B-COM) – MAC interfaces and functions (NTUST/EURECOM)
NB-ioT-OAI-Workshop, April 28, 2017 Beijing
Objectives and Team
Strong interest identified for bringing NB-IoT into OAI
OAI could become tool to test NB-IoT eNB or UE quickly – Will do interband, guardband (combined with eMBB) and isolated
solution – Interconnected with
OAI Playground @ EURECOM=> build MEC IoT applications
– Test NB-IoT / LTE interop on common eNB
What is needed – New Rel 13/14 physical channels to be implemented (simpler than LTE)
“one”-PRB version of LTE
– L2 stack, largely the same Main work in RRC layer
– Openair-CN extensions in support of NB-IoT (SCEF for non-IP applications)
NB-ioT-OAI-Workshop, April 28, 2017 Beijing
Objectives and team
Current NB-IoT team
NB-ioT-OAI-Workshop, April 28, 2017 Beijing
Ray Cheng (NTUST) Eric HSIEH (NTUST) Nick Ho (NTUST) Calvin Hsu (NTUST) Kenny Chen (NTUST) Xavier Liu (NTUST)
Alan Lee (NTUST) Michele Paffetti (UBologna) Rodolphe Legouable (B-COM)
Matthieu Kanj (B-COM)
Vincent Savaux (B-COM)
Objectives and team
Weekly meetings (Tuesdays 10h30 CET, webex) Physical meeting with B-COM/Orange/Nokia/TCL : 14/03/2017 git repo: gitlab.eurecom.fr/oai/openairinterface5g, branch
develop-nb-iot – Synchronized regularly with main develop branch – Merge requests handled by B-COM into develop-nb-iot
Main targets for NB-IoT – eNB functionality by July 2017
Integration with openairCN (added functionality in MME) Integration with Nokia µcore Testing with first COTS devices
– NFAPI NB-IoT interface Implementation will be aligned with small-cell forum NFAPI. This is currently already
finalized. We will receive the reference implementation from Cisco. – UE in second phase, discussions with one IP vendor on UE implementation in community.
Interested parties should speak up. UE L1 will be done to test L1 eNB
Main targets for eMTC – Rel 14 eNB physical channels and procedures starting in July 2017 – Collaboration with Orange (Egypt and France) – Starting point for NR phase 2 (5GMTC)
NB-ioT-OAI-Workshop, April 28, 2017 Beijing
RRC NB-IoT Overview and Differences Reduced set of RRC procedures:
No connected mode mobility (handover and measurement reporting) No Dual Connectivity No MBMS (Rel.13) …
Same RRC state as in LTE: RRC_CONNECTED & RRC_IDLE Signaling radio bearer are partly re-used from LTE:
o SRB0 for RRC messages transmitted over the CCCH logical channel o New signaling radio bearer SRB1bis implicitly configured with SRB1 using the same configuration, however
without the PDCP SRB1 takes the role of the SRB1 until security is activated o There is no SRB2 defined
Subset of the SIBs defined for NB-IoT with a reduced and/or modified set of information elements: o Basic:
MIB-NB (new design): schedulingInfoSIB1, SystemInfoValueTag, ab-Enabled SIB1-NB, SIB2-NB, SIB3-NB (Actually implemented in OAI), SIB4-NB, ..
o NB-IoT (Rel.14.2.1): SIB15-NB, SIB20-NB, SIB22-NB (not supposed to be implemented in OAI)
System information acquisition and change procedure is only applied in the RRC_IDLE state. Same RRC Connection Establishment/Reestablishmen/Release and Paging procedure as in
LTE – Need to implement paging here + RRCConnectionReestablishment
RRC Connection Reconfiguration: – Multi Carrier Configuration (non-anchor carrier) – No mobilityControlInfo (handover not supported)
New RRC Connection Resume/Suspension procedures signaling reduction for re-establishing RRC connection (also in regular LTE)
RRC Status
RRC ASN.1 messages (Rel-14) integrated – MIB,SIB (1,2,3) – RRCConnectionRequest extraction – RRCConnectionSetup generation – RRCConnectionSetupComplete extraction – RRCConnectionReject generation – ULInformationTransfer extraction – DLInformationTransfer generation – UECapabilityEnquiry generation – UECapabilityInformation extraction – SecurityModeCommand generation – SecurityModeComplete extraction – RRCConnectionRelease generation – RRCConnectionReconfiguration generation – RRCConnectionResume generation (*** new) – RRCConnectionResumeRequest extraction (***new) – RRCConnectionReestablishmentRequest extraction – RRCConnectionReestalishment generation (***to be added) – RRCConnectionReestablishmentReject generation – Paging-NB (***to be added)
State machine from LTE eNB refitted for NB-IoT – Interfaces with lower layers (PDCP,RLC,MAC) defined and integrated
Still some issues with SRB1bis – Transparent interfaces (BCCH,CCCH) implemented directly between MAC and RRC (i.e. no PDCP/RLC transparent
mode)
Paging needs to be implemented still (will push to LTE at the same time)
NB-ioT-OAI-Workshop, April 28, 2017 Beijing
MAC/PHY Interfaces
Follow a FAPI-compatible interface => integrate with NFAPI solution provided by Cisco in OAI
NB-ioT-OAI-Workshop, April 28, 2017 Beijing
FAPI P7 FAPI P5
Adaptation of OAI MAC-PHY primitives
NB-ioT-OAI-Workshop, April 28, 2017 Beijing
MAC/PHY interface is defined
MAC Scheduler will be implemented in May in parallel to completion of L1 procedures
L1 status – DL : NPSS / NSSS and Reference signals completed – DL : NPBCH under implementation – DL : NPDCCH, NPDSCH nothing yet – UL : nothing yet
Unitary simulators to be finished first => basic UE implementation
eNB NB-IoT procedures in parallel to MAC scheduler NB-ioT-OAI-Workshop, April 28, 2017 Beijing
Conclusions
There will be NB-IoT in OAI very soon – Testing will be possible as of August
COTS UEs?
RF platforms – Anything should be ok
UE – Please provide an indication of community interest in this
activity, some industrial interest is there
NB-ioT-OAI-Workshop, April 28, 2017 Beijing