MAC - Network Entry in 802.16m

IEEE 802.16 Presentation Submission Template (Rev. 9) Document Number:

IEEE C802.16m-08/760r3Date Submitted:

2008-09-05Source:

Zexian Li, Andrea BacioccolaRoberto Albanese, Jan SuumakiJukka Ala-Vannesluoma Nokia E-mail: zexian.li@nokia.com

Yousuf Saifullah, Shashikant MaheshwariHaihong ZhengNokia Siemens Networks E-mail: yousuf.saifullah@nsn.com

Venue: RE: MAC: Network Entry. In response to the TGm Call for Contributions and Comments 802.16m-08/033 for Session 57

Base Contribution:This is the base contribution.

Purpose:To be discussed and adopted by TGm for the 802.16m SDD

Notice:This document does not represent the agreed views of the IEEE 802.16 Working Group or any of its subgroups. It represents only the views of the participants listed in the “Source(s)” field above. It is offered as a basis for discussion. It is not binding on the contributor(s), who reserve(s) the right to add, amend or withdraw material contained herein.

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Outline

• Overview:16e initial network entry overview

• Proposal: 16m initial network entry – will have impacts on

• Handover

• Idle mode exit

• Un-controlled Handover

Background and motivation

• According to SRD, latency should be further reduced as compared to the WirelessMAN-OFDMA Reference System for all aspects of the system including the air link, state transition delay, access delay, and handover.

• In 16e (as shown in the next slide), MS has to detect both MAP and DCD/UCD messages in order to enter the network successfully. Since DCD/UCD are not transmitted in every frame, significant latency can not be avoided if the transmission interval of DCD/UCD is larger.

• In 16m, in order to speed up the network entry process, different new schemes have been proposed in DL Control (section 11.7 of SDD) such as – Classifying the system configuration information and separating information

related to network entry– Superframe concept:

• Define broadcast channel (including both PBCH and SBCH) to carry deployment-wide and sector-wide information for network entry/re-entry.

• Transmission PBCH and SBCH in super frame header.

UCD

Ranging code

RNG-RSP

MS BS

Preamble

Synchronized at PHY layer (indicated by PHY Indicator)

MS power on, scan for the channel in pre-defined

frequency sets

DCD, DL-MAP

Obtain DL parameters

Obtain UL parameters

MS randomly selected CDMA codes and subchannel for

initial ranging

UL-MAP

RNG-RSP with adjustment parameters and original Ranging Code and Ranging Slot,

Status=success

Adjust TX parameters according to RNG-RSP Time to send CDMA Initial Ranging opportunity,

send MAP containing CDMA Allocation IE with broadcast CID

UL-MAPRNG-REQ

RNG-RSP

SBC-REQ

SBC-RSP

REG-REQ

REG-RSP

Authentication and Key generation

Connection establishment (DSA-REQ/RSP/ACK)

Summarized 16e Initial Network Entry Procedure

• PHY synchronization• MAC synchronization (including

getting DCD/UCD, DL-MAP/UL-MAP)

– Optimized in 16m with new designed DL control channel

• Ranging process

• Basic capability exchange

• Authentication and key generation

• Registration

• Connection setup

DL Control Optimization

PHY about 16m SCH

16m Frame Structure and DL Control Structure

• Example of basic frame structure

• Essential system parameters mapping (SDD, section 11.7.3)

Example of necessary information for initial network entry

• UL Frequency

• Frequency lists

• Cell type

• Superframe number

• Subframe configuration information

• BS ID (incl. NAP ID)

• NSP ID

• BS EIRP

• EIRxP_IR, max

• TTG/RTG

• MAC version support

• Available DL/UL resource

• UL PHY mode ID

• MS transmit power limitation level

• Initial ranging codes/region, backoff_start/end

• BW request codes/region, backoff_start/end

Network entry for 16m MS

• How 16m MS can find 16m subframes– Green field:

• 16m MS needs to get synchronized with 16m SCH which might appear in every superframe or every frame (depending on the agreement in TGm)

• If there is fixed location relationship between 16m SCH and the super frame header which includes BCH, all the necessary information for initial NE, then after PHY synchronization MS can get the content of BCH within super frame header.

• MS can start ranging process• Authentication• Service flow set up

– Mixed scenarios:• Similar as Green field case, only difference is legacy preamble might be

help for synchronization and channel estimation.

Possible optimization items for latency reduction

• Different ways of transmission of essential static information such as BS ID, NSP ID

– Splitting and transmission of essential static information such as BS ID, NSP ID etc. into multiple frames or multiple superframes by taking into account overhead and latency requirements

• Possibility of combining messages e.g. SBC-REQ/RSP, REG-REQ/RSP into RNG-REQ/RSP?

– For example, including/negotiating only SBC-Capabilities that are required for “authentication and initial communication” to be included in RNG-REQ. Once authentication is successful, MS can include remaining SBC-capabilities in REG-REQ.

– Although SBC exchange does not bring much latency, by doing so, it reduces the overhead and simplify the design in addition to latency reduction.

Possible optimization items for latency reduction

• NSP information obtaining from Service Identity Information (SII-ADV)

– MS asking NSP info• Using specific CDMA codes during initial ranging• Or using specific TLV in RNG-REQ• Or new MAC management message

– BS can response with request information in SII-ADV. Depending on the number of MSs asking, the message can be broadcasted or unicasted.

• Definition of ranging sequences– Per user class– Per sector

Example of 16m initial network entry procedure

• PHY synchronization• MAC synchronization• Ranging process• Authentication• Registration• Service flow set up

MS BS

Preamble/SYN

Synchronized at PHY layer (indicated by PHY Indicator)

MS power on, scan for the channel in pre-defined

frequency sets if available

BCH (incl. both PBCH and SBCH)

Obtain essential system parameters for both DL&UL

Authentication set up procedure

Initial ranging CDMA code

RNG-RSP

RNG-REQ (incl. TLVs from SBC-REQ)

RNG-RSP (incl. TLVs from SBC-RSP)

REG-REQ (incl. TLVs from SBC-REQ)

REG-RSP ( (incl. TLVs from SBC-RSP))

Initial service flow setup

Network re-entry

• Network re-entry from different scenarios– Idle mode– Handover– Un-controlled HO due to signaling loss

• Network re-entry of 16m MS will follow the procedure of initial network entry except the latency can be further reduced by optimizing the procedures– MS context already known by the network– Many steps can be completed during preparation phase

which does not affect service interruption time

Proposed SDD Text

• 10.x Network entryNetwork entry is the procedure by which an MS finds and establishes a connection with the network. The network entry procedure includes:– MS synchronizes with the BS via synchronization channel (SCH). – MS obtains necessary information e.g. BS ID, NSP ID for initial network

entry, from PBCH/SBCH and perform network selection. – MS starts ranging process.– Authentication and registration process. – MS enters 16m network and sets up service flows.

Neighbour BSs search is based on the same downlink signals as initial network search except some information can be provided by serving BS. Network re-entry from such procedures as handover, idle mode exit and so on, is based on initial network entry procedure with certain optimization procedures.