IEEE C802.16m-09/0608
Project
IEEE 802.16 Broadband Wireless Access Working Group <http://ieee802.org/16>
Title
Proposed text of legacy support handover section for the IEEE 802.16m Amendment
Date
Submitted
2009-03-02
Source(s)
Jaehyuk Jang
Rakesh Taori
Jung Je Son
Samsung Electronics
E-mail:
jack.jang@samsung.com
Changhoi Koo
Huawei Technologies
E-mail:
ckoo@huawei.com
*<http://standards.ieee.org/faqs/affiliationFAQ.html>
Re:
IEEE 802.16m-09/0012 Call for Contributions on Project 802.16m AWD
Regarding SDD section 10.3 Handover
Abstract
The contribution proposes the text of legacy support handover section to be included in the
802.16m amendment.
Purpose
To be discussed and adopted by TGm for the 802.16m amendment.
Notice
Release
Patent
Policy
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Proposed text of legacy support handover section for the IEEE
802.16m Amendment
Jaehyuk Jang, Rakesh Taori, Jung Je Son
Samsung Electronics
Changhoi Koo
Huawei Technologies
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IEEE C802.16m-09/0608
Introduction
This contribution provides amendment text for the MAC HO procedures in the Advanced Air Interface to be
included in Section 15 of the IEEE 802.16m Amendment Working Document.
Reference
[1] IEEE 802.16m Amendment Working Document, IEEE 802.16m-08/050
Proposed Amendment Text
The following text is proposed for inclusion in Section 15 of the IEEE 802.16m Amendment Working
Document. Legacy support is the new feature in 802.16m, and the numbering of the section is based on the SDD
section numbering.
In 16e-to-16m handover scenario, 16m BS could be either mixed-mode BS or 16m-only BS. For the case of
handover from 16e to 16m-only BS, we need to provide solution for a 16m MS to handover to 16m-only BS.
Figure below illustrates high-level flow.
AMS
YBS
ABS
SII-ADV
(including list of YBSs)
Scanning and
measurement
MSHO-REQ
(using BS-ID obtained from
the SII-ADV message)
HO-Request
HO-Response
BSHO-RSP
HO-ACK
HO-IND
HO-Confirm
HO-ACK
Random access for re-entry
RNG-REQ
RNG-RSP
(including AMS identity (e.g., STID, FIDs, TEK)
Figure 1 MSC for 16e-to-16m handover
To support handover to 16m-only BS efficiently, a 16e BS needs to provide neighbor list of 16m-only BSs. We
propose to use the SII-ADV message to carry neighbor 16m BS’ information. The SII-ADV message may
include the parameters which is required to perform handover (e.g., BS ID, FA index, Preamble index, P/S-BCH
or DCD/UCD information) Based on the information from the SII-ADV message, an 16m MS tries to scan
neighbor 16m BSs. The legacy MS ignores the unknown contents of the SII-ADV message.
When performing handover to the 16m BS, the 16m MS attached to the 16e BS simply performs handover
preparation/execution according to the 16e procedures. The 16m MS requests handover with the desired BS-ID
of 16m BS obtained from the SII-ADV message. Then 16e BS responds with the BSHO-RSP message with
appropriate values. All fields in BSHO-RSP message (Neighbor BSID, Service level prediction, HO process
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IEEE C802.16m-09/0608
optimization, and HO authorization policy indicator) except preamble index field can be reused. The 16m BS
instructs the 16e BS how to populate the Preamble index field. In other words, message composition method at
the 16e BS is unchanged. The 16m MS ignores the preamble index field in the BSHO-RSP message, and will
use value of preamble index obtained from the SII-ADV message.
When handover is executed, the serving 16e BS transfers context to the target 16m BS according to the known
procedures (outside of scope of 802.16)
Since the MS cannot get dedicated ranging resources and station ID at the 16m BS through the 16e BS, the 16m
MS uses random access for performing re-entry to the 16m BS. The 16m MS and the 16m BS exchange RNGREQ/RSP message in the usual way, and during this transaction, 16m MS will update TEK, STID, FIDs.
15.2 Medium access control
15.2.x MAC HO procedures
15.2.x.3 HO Process supporting Legacy system
15.2.x.3.1 Network topology acquisition
(Note: A WirelessMAN-OFDMA Reference System/WirelessMAN-OFDMA Advanced System co-existing BS
transmits two types of preambles, i.e., one is for WirelessMAN-OFDMA Reference System and the other is for
the AAI specified in section 15.x.x.x)
A WirelessMAN-OFDMA Reference System/WirelessMAN-OFDMA Advanced System co-existing BS
transmits the AAI-MOB_NBR-ADV message in MZone to broadcast information of neighbor BSs. The AAIMOB_NBR-ADV message may include information of YBSs as well as that of ABSs including WirelessMANOFDMA Reference System/WirelessMAN-OFDMA Advanced System co-existing BSs. The AAI-MOB_NBRADV message shall include the preamble index of WirelessMAN-OFDMA Reference System for a
WirelessMAN-OFDMA Reference System/WirelessMAN-OFDMA Advanced System co-existing BSs. The
AAI-MOB_NBR-ADV message is described in XXXXX (The definition of the message is required).
A YBS sends MOB_NBR-ADV message to advertise information of neighbor BSs including both YBSs and
WirelessMAN-OFDMA Reference System/WirelessMAN-OFDMA Advanced System co-existing BSs. A
WirelessMAN-OFDMA Reference System/WirelessMAN-OFDMA Advanced System co-existing BS sends
MOB_NBR-ADV message (specified in 6.3.2.3.42) to LZone in order to provide information both of YBSs and
WirelessMAN-OFDMA Reference System/WirelessMAN-OFDMA Advanced System co-existing BSs. The
Preamble Index/Subchannel Index field in the MOB_NBR-ADV message shall only include preamble index of
WirelessMAN-OFDMA Reference System when BS advertises information of WirelessMAN-OFDMA
Reference System/WirelessMAN-OFDMA Advanced System co-existing BS.
15.2.x.3.2 HO from a YBS to an ABS
A YMS performs handover from a YBS to a LZone of WirelessMAN-OFDMA Reference
System/WirelessMAN-OFDMA Advanced System co-existing BS using WirelessMAN-OFDMA Reference
System handover signaling and procedures defined in 6.3.21.2.
An AMS performs handover from a YBS to an ABS using either zone switching or direct handover. The detailed
procedures for zone switching and direct handover are described in 15.2.x.3.2.1 and 15.2.x.3.2.2, respectively.
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IEEE C802.16m-09/0608
15.2.x.3.2.1 Zone switching
An AMS may handover from the serving YBS to the LZone of the target ABS, and switch to the MZone of the
ABS. This feature is only applicable to a WirelessMAN-OFDMA Reference System/WirelessMAN-OFDMA
Advanced System co-existing BS.
15.2.x.3.2.2 Direct handover
An AMS may also handover from a YBS to an ABS directly. This feature is applicable to both a WirelessMANOFDMA Reference System/WirelessMAN-OFDMA Advanced System co-existing BS and a 16m-only ABS.
An AMS attached to a YBS obtains information of neighbor ABSs through the SII-ADV message. The SII-ADV
message contains ABS information TLV which includes ABS-specific parameters (e.g., BS ID, FA index,
Preamble index of ABS, P/S-BCH or DCD/UCD information of ABS) of neighbor ABSs. A YBS may manage
the list of neighbor ABSs, but a YBS shall not send information of neighbor ABSs through the NBR-ADV
message.
During HO from a YBS to an ABS, an AMS requests handover using legacy MSHO-REQ message with the
desired BS-ID obtained from the SII-ADV messages. The YBS may communicate with the ABS(s) during
handover, and populate the fields in the BSHO-RSP message with appropriate values. The AMS ignores the
preamble index field in the BSHO-RSP message, and uses value of preamble index obtained from the SII-ADV
message.
The AMS uses random access for performing re-entry to the ABS. The AMS and the ABS exchange AAI-RNGREQ/RSP message after random access. During the AAI-RNG-REQ/RSP transaction, the AMS updates the
values related to AMS identity (e.g., TEK, STID, FIDs, etc).
15.2.x.3.3 HO from an ABS to a YBS
A YMS performs handover from an ABS to a YBS using WirelessMAN-OFDMA Reference System handover
signaling and procedures defined in 6.3.21.2.
When the handover from an ABS to a YBS is triggered for an AMS, the serving ABS and AMS perform
handover execution using handover signaling and procedures defined in 15.2.x.2. The serving ABS performs
context mapping and protocol interworking from the AAI to the WirelssMAN-OFDMA Reference System. The
AMS performs network re-entry to the target YBS using WirelessMAN-OFDMA Reference System network reentry signaling and procedures defined in 6.3.21.2.
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