MAC - Network Entry in 802.16m
IEEE 802.16 Presentation Submission Template (Rev. 9)
Document Number:
IEEE C802.16m-08/760r3
Date Submitted:
2008-09-05
Source:
Zexian Li, Andrea Bacioccola
Roberto Albanese, Jan Suumaki
Jukka Ala-Vannesluoma
Nokia
Yousuf Saifullah, Shashikant Maheshwari
Haihong Zheng
Nokia Siemens Networks
E-mail: zexian.li@nokia.com
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
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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 deploymentwide and sector-wide information for network entry/re-entry.
• Transmission PBCH and SBCH in super frame header.
Summarized 16e Initial Network Entry Procedure
MS
• 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
BS
MS power on, scan for the
channel in pre-defined
frequency sets
Preamble
PHY about 16m
SCH
Synchronized at PHY layer
(indicated by PHY Indicator)
DCD, DL-MAP
Obtain DL parameters
UCD
DL Control Optimization
Obtain UL parameters
UL-MAP
MS randomly selected CDMA
codes and subchannel for
initial ranging
Ranging code
RNG-RSP with adjustment parameters and
original Ranging Code and Ranging Slot,
Status=success
RNG-RSP
Adjust TX parameters
according to RNG-RSP
Time to send CDMA Initial Ranging opportunity,
send MAP containing CDMA Allocation IE with
broadcast CID
UL-MAP
RNG-REQ
RNG-RSP
SBC-REQ
SBC-RSP
Authentication and Key generation
REG-REQ
REG-RSP
Connection establishment (DSA-REQ/RSP/ACK)
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 SBCcapabilities 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
MS power on, scan for the
channel in pre-defined
frequency sets if available
Preamble/SYN
Synchronized at PHY layer
(indicated by PHY Indicator)
BCH (incl. both PBCH and SBCH)
Obtain essential system
parameters for both DL&UL
Initial ranging CDMA code
RNG-RSP
RNG-REQ (incl. TLVs from SBC-REQ)
RNG-RSP (incl. TLVs from SBC-RSP)
Authentication set up procedure
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 entry
Network 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.