Handover using Exclusive HO Ranging Channel
Document Number:
IEEE C802.16m-08/714
Date Submitted:
2008-07-07
Source:
Baowei Ji (bji@sta.samsung.com) and Changhoi Koo (chkoo@samsung.com)
Samsung Telecommunication America
Jaehyuk Jang (jack.jang@samsung.com), Sungjin Lee (steve.lee@samsung.com), Jungje Son
(jungje.son@samsung.com), Hyunjeong Kang (hyunjeong.kang@samsung.com) and Yeongmoon Son
(ymson1004@samsung.com),
Samsung Electronics
Venue:
Re:
Base Contribution:
Purpose:
Denver, Colorado
Call for contributions on project IEEE 802.16m: Upper MAC concepts and methods ( Mobility )
N/A
Discussion and consideration for SDD
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Comparison of HO procedures
Scheme
Ranging Code
Sharing
Code
Collision
Ranging Channel
Sharing
Multiple Access
Interference
(MAI)
Conventional HO
Yes
Yes
Initial ranging, HO
ranging, SRHO
Yes
Optimized HO
Exclusive HO
Ranging Channel
N/A
No
No
Among HO MS only
Controlled by
the target BS
Proposed HO scheme (1/4)
• Exclusive HO ranging channel is assigned by the target BS
– Notified during HO preparation stage (MOB_HO-REQ/RSP), together
with a unique ranging code
– Scheduled via the newly designed Exclusive_Ranging_IE()
• Expected Benefits
– No (ranging) code collision
• Each MS will use a distinct ranging code
– Multiple Access Interface (MAI) is controlled by the target BS
• A MS can use the ranging channel only with explicit assignment from the
target BS)
– Short HO interruption time
• Shortened ranging procedure
• MS identification from the unique ranging code
• Quick data exchanging resume
Proposed HO Scheme (2/4)
• The target BS will inform the MS through the serving BS
whether an exclusive ranging channel will be allocated for it.
– If an exclusive ranging channel is to be assigned,
• A certain timer will also be associated with it.
• A unique ranging code will be assigned for this MS
– The MS will use this exclusive ranging channel before the timer expires.
– If no exclusive ranging channel will be assigned, the MS will use a
shared ranging channel
Proposed HO Scheme (3/4)
Serving
BS
MS
Anchor
ASN
HO preparation time
MOB_MSHO_REQ
HO-Request
Context Transfer
- Exclusive ranging channel
- Unique ranging code
MOB_BSHO_RSP
HO interruption time
MOB_HO_IND
Bearer Path Registration
HO-Response
HO-Ack
HO-Confirm
HO-Ack
Exclusive_Ranging_IE() with exclusive ranging channel
Ranging (using unique code over exclusive channel)
RNG-RSP (success with time advancement) and UL allocation
RNG-REQ (CMAC) & UL data
RNG-RSP (CMAC) & DL data
BW-REQ (0 or BW)
Bearer Path De-registration
Operational (data transfer)
Target
BS
Proposed HO Scheme (4/4)
• If timing is not essential,
conventional HO could be
used.
• If timing is essential
Normal Operation
HO decision
No
Conventional HO
Yes
Optimized HO
HO interruption time <
threshold?
– If time alignment could
be done without explicitly
transmitting ranging code,
optimized HO could be
used
– If autonomous TA cannot
be done, Exclusive HO
should be used.
Yes
Time aligned
automatically ?
No
To assign exclusive
ranging channel ?
Yes
No
Receive
Exclusive_Ranging_IE() ?
No
Yes
Use shared ranging
channel
Timer expires ?
Yes
Use exclusive ranging
channel
No
Proposed Text
• Following Text should be included into SDD document
-------------------- Start Text --------------------------------------------10.X Handover operation
To avoid excessive multiple access interference in handover
ranging process, the target BS should control the multiple
access interference by scheduling a ranging channel dedicated
for handover purpose only. The target BS should assign each
MS a unique ranging code also to avoid code collision.
--------------------- End of Text ------------------------------------------
Slide 7