Some Considerations about 16m Network Architecture
Document Number: IEEE C802.16m-08_491r1
Date Submitted: 2008-5-8
Source:
Qu Hongyun, Fang Huiying, Liu Yang, Chen Yuqin
Sean Cai, Jerry Chow, Xu Ling
ZTE Corporation
E-mail: qu.hongyun@zte.com.cn
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content of IEEE 802.16m-08/003r1.”
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Introduction
• In current SDD document 802.16m-08_003r1, the section 4
describes the overall network architecture for 16m system,
including the air interface with relay station, as the following figure.
Problems
•
Problem-1
– If 16m BS can operate with 16j RS, it means 16m BS has to include the capabilities same
with 16j BS, which is referred to MR-BS in current 16j draft standard. In other words,
16m BS has to backward support reference system with functionalities to support 16j RS.
– Actually according to the legacy supporting requirement in 16m SRD, the legacy
reference system is defined by WiMAX Mobile System Profile, which does not include
the definition of 16j BS.
– So if 16m BS can operate with 16j RS, the capability of backward compatibility of 16m
BS is extended to support 16j BS. It is not a requirement of 16m SRD. And it will cause
high complexity for 16m BS, because 16m BS has to support at least three air interfaces,
including16e, 16j, and 16m. If the air interfaces between 16mMS-16mBS and 16mRS16m BS are different, then 16m BS has to support four air interfaces.
•
Problem-2
– From another perspective, in current 16j draft standard, there is a lot of optional features
to support the same functionality. It does not meet the complexity requirements of 16m
for minimum optional features.
•
Problem-3
– Currently 16jm adhoc suggest to support the connection between 16m BS and 16j RS
under such a assumption that a 16j relay profile will be defined, which is not necessary in
IEEE 802.16 WG.
– We do not think this assumption makes sense. Obviously, IEEE 802.16 WG will not
define this 16j relay profile. And actually the activities outside of IEEE 802.16 WG can
not be controlled by IEEE 802.16 WG.
Our Opinion
• Our suggestion is as follows.
– 16m BS should not support 16j RS.
– 16m RS may support legacy 16e MS.
– Referring to the design schemes currently in 16j draft
standard as many as possible, when 16m RS is designed.
• Reason:
– It will reduce the implementation complexity of 16m BS,
compared with 16m BS with supporting 16j RS.
– It will reduce the redundancy of relay station, because 16m
RS will be defined and it can support both 16e MS and
16m MS.
Text Proposal
• To replace the Figure 2 in the Section 4 with the
following Figure:
802.16e
MS
802.16m
RS
802.16m
BS
802.16m
MS
802.16e
MS
802.16m
BS
802.16m
MS
802.16m
BS
Figure 2 - Relay Station in Overall Network Architecture
Text Proposal
• To replace the current paragraph below the
Figure 2 in the Section 4 with the following
text:
• A 16m RS that is capable of supporting a
legacy MS, shall communicate with the legacy
MS in the "legacy zone". The design of 16m
relay protocols should refer to the design of
16j wherever possible.