IEEE C802.16m-09/1350
Project
IEEE 802.16 Broadband Wireless Access Working Group <http://ieee802.org/16>
Title
Text Proposal for 16m HO Procedure (AWD-15.2.6)
Date
Submitted
2009-07-06
Source(s)
Xiangying Yang
Muthaiah Venkatachalam
Intel
Re:
E-mail:
xiangying.yang@intel.com
IEEE 802.16m-09/0028r1. ”AWD call for contribution after session #61”
Category: AWD/Area: Chapter 15.2.6 (AWD-15.2.6)
Abstract
This contribution proposes text for HO network re-entry procedure in 16m.
Purpose
Adopt proposed text.
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Text Proposal for 16m HO Procedure (AWD-15.2.6)
Xiangying Yang, Muthaiah Venkatachalam
Intel
I.
Text proposal for 16m-16m HO
In 16m HO, the HO command contains different flags related to HO network re-entry depending HO
optimizations. These flags are mainly related to timing adjustment and MAC context/security update readiness.
The network re-entry behavior should be clearly defined based on the issued HO command, to ensure the HO
operation completes in a good network control.
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IEEE C802.16m-09/1350
In this contribution, we propose text to clarify the procedure.
Proposed text #1:
-------------------------------------------text #1 start---------------------------------------------15.2.5.2.5.1 CDMA-based HO Ranging Procedure
The serving ABS indicates in the AAI_HO-CMD how CDMA HO ranging shall be performed by MS
during network re-entry, as shown in Figure ZZZ.
Y
Seamless HO
CDMA_RNG_flag
N
N
CDMA_RNG_flag
Y
Y
Use dedicate ranging
code/opportunity
Dedicated RNG
code/opportunity
Y
Use it
N
N
RNG-RSP
continue
Pick randomly
RNG-RSP
success
continue
success
Data communications w/ TBS
&
RNG-REQ/RSP transaction
RNG-REQ/RSP transaction
HO complete
Figure ZZZ MS state machine during HO network re-entry
If the serving ABS indicates in AAI_HO-CMD that CDMA-based HO ranging is not omitted by setting
CDMA_RNG_FLAG=1 and a dedicated ranging code/opportunity is assigned to the AMS by target
ABS, the AMS shall transmits the dedicated ranging code to the target ABS during network re-entry. If
a ranging channel is scheduled by the target ABS for handover purpose only, the AMS should use that
ranging channel in order to avoid excessive multiple access interference. Upon reception of the
dedicated ranging code and if ranging is successful, the target ABS shall allocate uplink resources for
AMS to send AAI_RNG-REQ message and/or UL data. If the target ABS does not receive the
dedicated ranging code within TBD Ranging_Initiation_Deadline Timer, the target ABS shall discard
the pre-assigned STID of the AMS.
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IEEE C802.16m-09/1350
If CDMA-based HO ranging is not omitted and if an AMS does not have a dedicated ranging code or a
dedicated ranging opportunity at the target BS, the AMS shall transmit a random handover ranging
code at the earliest available ranging opportunity.
If the serving ABS determines that the AMS will be sufficiently synchronized with the target ABS and
indicates in AAI_HO-CMD that CDMA based ranging can be skipped while performing network entry
at the target ABS by setting CDMA_RNG_FLAG=0, the AMS shall apply the independently calculated
adjustments when starting network entry at the target ABS by comparing A-Preamble signal timing
measurements of the target ABS to serving ABS measurements.
Regardless of whether CDMA ranging is omitted or not, the serving ABS may send AAI_RNG-RSP
message with timing/power adjustment parameters for which the MS shall apply for subsequent uplink
transmissions. The serving ABS may also send AAI_RNG-RSP message with ranging status “continue”
so that the AMS shall perform CDMA ranging with randomly selected HO ranging code in the next
earliest ranging opportunity to adjust its uplink transmission timing/power properly.
If the serving ABS indicates that CDMA ranging cannot be skipped, the serving ABS may allocate a
dedicated ranging code/opportunity to the AMS in AAI_HO-CMD message. If a dedicated ranging
code or a dedicated ranging opportunity is included in HO-CMD, the AMS shall perform CDMA
ranging at the target ABS using the dedicated ranging code and/or ranging opportunity.
The serving ABS may explicitly inform the AMS to omit CDMA ranging though AAI_HO-CMD if it
determines that the AMS will be well-synchronized with the target ABS after self-adjustment of its
timing based on the following conditions:
- Intra-FA HO
- SBS and TBS belong to the same synchronized network (e.g. not applicable to femtocell deployment
where femtocell BS only achieves rough synchronization over the air.)
- Cell sizes are smaller than TBD threshold
-------------------------------------------text #1 end----------------------------------------------
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IEEE C802.16m-09/1350
II.
Text proposal for 16e-16m HO
The zone switching procedure is different from HO in that there is no scanning or preparation stage. It is critical
for the AMS to obtain enough MZone information before network reentry to MZone to ensure successful Zone
Switching.
Proposed text #2:
-------------------------------------------text #2 start---------------------------------------------15.2.6.4.1.2.1 Zone Switch based Handover Procedure
The Zone Switch TLV shall include the following:
-
Zone_Switch_Action_Time, which shall ensure enough time for MS to obtain system
information of MZone before zone switching operation
-
MZone-LZone subframe offset
-
MZone APreamble index
-
STID for being used in MZone
{TBD}
The Zone Switch TLV may also include the following:
-
UL grant for the AMS to send AAI_RNG-REQ message in Mzone
-
STID for being used in MZone
Upon receiving the Zone Switch TLV, If synchronization with the MZone has not been accomplished,
the AMS starts network reentry in MZone by performing performs DL synchronization with the
MZone using the system information provided in the Zone Switch TLV through RNG-RSP message
sent by the ABS in LZone, before it starts network reentry in MZone. If the AMS hasn’t acquired SFH
of the MZone, the AMS shall acquire the system information of the MZone by listening to the ABS’s
SFH before network reentry in MZone.
The AMS shall also perform capability negotiation during network reentry in MZone through the
exchange of AAI_SBCREG-REQ/RSP message and subsequent key agreement and security key update.
AMS context mapping from LZone to MZone is performed by the ABS per section 15.2.x.4.2.3.
-------------------------------------------text #2 end---------------------------------------------III.
Text proposal for 16e-16m HO
For 16e/16m mixed-mode ABS, it incurs a lot of overhead if the ABS broadcast neighbor LZone or 16e BS
information in both its LZone MOB_NBR-ADV and its MZone AAI_NBR-ADV. We propose the ABS only
broadcast the indication of legacy 16e BS or LZone along with key parameters in AAI_NBR-ADV. The MS,
upon reading the indication, will try to obtain the full system information associated with 16e BS or LZone from
MOB_NBR-ADV in LZone.
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IEEE C802.16m-09/1350
Proposed text #3:
-------------------------------------------text #3 start---------------------------------------------15.2.5.3.2 Handover from Advanced WirelessMAN-OFDMA System to WirelessMAN-OFDMA
Reference System
15.2.5.3.2.1 Network Topology Acquisition
15.2.5.3.2.1.1 Network Topology Advertisement
In the WirelessMAN-OFDMA Reference System/WirelessMAN-OFDMA Advanced co-existing
System, an ABS shall broadcast the system information of its neighboring YBS and LZone of ABS in
its LZone using MOB_NBR-ADV message, and an ABS shall broadcast the existence of its
neighboring YBS and LZone of ABS in its MZone using AAI_NBR-ADV. An AMS by reading the
indication of existence of neighbor YBS or LZone of ABS in AAI_NBR-ADV, always obtains the
neighbor YBS information from the MOB_NBR-ADV message transmitted in its serving ABS LZone.
A reference pointer indicating the time offset of the MOB_NBR_ADV message transmission in LZone
is provided.
-------------------------------------------text #3 end----------------------------------------------
5