Proposal on Update of S-SFH
Document Number: C80216m-10_XXXX
Date Submitted: 2009-XX-XX
Source:
Xianming Chen, Yanfeng Guan, Lei Zhang, Feng Xie, Yang Liu
E-mail: guan.yanfeng@zte.com.cn
ZTE Corporation
Venue:
IEEE Session #66, Orlando, Florida, USA.
Category: P802.16m_D4 comments/Area: Chapter 16.2.23 Update of S-SFH IEs
Base Contribution: This is base contribution
Purpose:
For TGm discussion and adoption of P802.16m_D4 text.
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.
Release:
The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an
IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s
sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this
contribution may be made public by IEEE 802.16.
Patent Policy:
The contributor is familiar with the IEEE-SA Patent Policy and Procedures:
<http://standards.ieee.org/guides/bylaws/sect6-7.html#6> and <http://standards.ieee.org/guides/opman/sect6.html#6.3>.
Further information is located at <http://standards.ieee.org/board/pat/pat-material.html> and <http://standards.ieee.org/board/pat >.
Issue Introduction
• When the system information is changed, it is generally desirable for the
active AMSs to acquire and apply updated system parameters as soon as
possible, for the purpose of the improvement of current system
bandwidth utilization or network coverage.
• However, the time interval for update may be long, if S-SFH SPx
scheduling periodicity is set based on a longer interval, i.e. 160ms or
320ms, and if transmission times (i.e. 4) of each changed S-SFH SP
before taking effect is guaranteed.
• Besides, within the equivalent time interval beginning from SP change
superframe, the probability of decoding correctly of the S-SFH SP with
long scheduling period is much smaller than that of the S-SFH SP with
short scheduling period.
• This can cause that the active AMSs can not receive and apply updated
system information in a timely fashion.
Proposed Solution
• During the update process, the update method is the same for each SP.
– ABS may adjust the scheduling period for each SP, and it can equal
the minimal SP scheduling period supported by ABS, such as current
SP1 scheduling period.
– After the updated SP has taken effect, ABS can restore the adjusted
SP scheduling period to the original value before the update process.
• For example: Assuming that SP1 scheduling periodicity is 40ms (2
superframes), SP2 scheduling periodicity is 80ms (4 superframes), SP3
scheduling periodicity is 160ms (8 superframes), and the changed SP is
transmitted four times before it taking effect. Then, SP1, SP2 and SP3
need 160ms (8 superframes), 320ms (16 superframes) and 640ms (32
superframes) before the changing taken effect respectively. By decreasing
SP2 or SP3 scheduling periodicity, SP2 needs much less than 320ms (16
superframes) before the changing taken effect, and SP3 needs much less
than 640ms (32 superframes) before the changing taken effect.
Advantage
• This method ensures that an active AMS can acquire and apply
the up-to-date system information as soon as possible, and the
SPs with different period may have a little difference of
decoding probability for an AMS.
Figure 1 for Solution
Current SP Scheduling Method in D4
Superframe n+1 ~ n+8
SP1(40ms)
SP2(80ms)
SP3(160ms)
Proposed SP Scheduling Method
Superframe n+1 ~ n+8
Superframe n+9 ~ n+16
SP3 Update Duration
Superframe n+17 ~ n+24
Superframe n+25 ~ n+32
SP1(40ms)
SP2(80ms)
SP3(160ms, but 40ms in update process)
This figure above gives a case that ABS decreases SP3 scheduling periodicity
during SP3 update, when each SFH subframe can allow two S-SFH SPs to be
transmitted simultaneously.
Figure 2 for Solution
Current SP Scheduling and Update Method in D3
Superframe n+1 ~ n+8
SP1(40ms)
SP2(80ms)
SP3(160ms)
Proposed SP Update Method
Superframe n+1 ~ n+8
Superframe n+9 ~ n+16
SP3 Update Duration
Superframe n+17 ~ n+24
Superframe n+25 ~ n+32
SP1(40ms)
SP2(80ms)
SP3(160ms, but 80ms in update process)
This figure above gives another case that ABS decreases SP3 scheduling
periodicity during SP3 update, when each SFH subframe can only allow one SSFH SP to be transmitted due to the lack of resource.
Proposed Text
• Add the new text in page 336, line 56 in section 16.2.23
When the system configuration information in S-SFH SP 2 IE and/or S-SFH SP 3
IE has changed, the ABS shall adjust the SP 2 and/or SP 3 scheduling periodicity to
a smaller value supported by ABS depending on the system configuration. When
the new S-SFH information is used, the ABS can restore the adjusted SP scheduling
periodicity to the original value.