IEEE C802.16j-07/432r3
Project
IEEE 802.16 Broadband Wireless Access Working Group <http://ieee802.org/16>
Title
Tunnel Convergence sub-layer function of RS in moving BS mode
Date
Submitted
2007-07-18
Source(s)
Hang Zhang, Peiying Zhu, Mo-Han Fong,
Wen Tong, David Steer, Gamini
Senarath, G.Q. Wang, Derek Yu, Israfil
Bahceci, Robert Sun and Mark Naden
Nortel
3500 Carling Avenue
Ottawa, Ontario K2H 8E9
Voice: +613-763-1315
E-mail: wentong@nortel.com
Voice: +613-765-8983
E-mail: pyzhu@nortel.com
Kanchei (Ken) Loa, Hua-Chiang Yin,
Yi-Hsueh Tsai, Shiann Tsong Sheu,
Yung-Ting Lee, Youn-Tai Lee
Institute for Information Industry
8F, No. 218, Sec. 2, Dunhua S. Rd.,
Taipei City 106, Taiwan
ROC
Voice: +886-2-27399616
E-mail: loa@iii.org.tw
Re:
IEEE 802.16j-07/019: “Call for Technical Comments Regarding IEEE Project 802.16j”
Abstract
In this contribution, the required functions in an access RS in moving BS mode and the required
functions in a MR-BS supporting such a RS are addressed.
Purpose
To incorporate the proposed text into the P802.16j Baseline Document (IEEE 802.16j-06/026r4)
Notice
Release
Patent
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CPS Sub-layer Function of Moving RS Type-II
Hang Zhang, Peiying Zhu, Mo-Han Fong, Wen Tong, David Steer, Gamini Senarath, G.Q. Wang,
Derek Yu, Israfil Bahceci, Robert Sun and Mark Naden
Nortel
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IEEE C802.16j-07/432r3
1 Introduction
In current baseline document, a movin RS can work in moving RS mode or in a moving BS mode (refer to
6.3.22.4.1.1). The corresponding data forwarding protocol is described in section 1.4.3, where the access RS
needs to implement a simple CPS sub-layer function. In this contribution, the required functions in an access RS
in moving BS mode (mobile RS Type-II) and the required functions in a MR-BS supporting such a RS are
addressed.
2 Statement of Problem
2.1 Architectural issues for supporting mobile RS

For the non-tunneling configuration, when MRS is moving from serving MR-BS to target MR-BS, this
will cause unnecessary handover of MS(s) associated with MRS.

For the case of single tunnel is employed, the moving RS in the baseline assumes that all MAC context
related to MS(s) are transferred via backhaul from serving MR-BS to target MR-BS, For the case mobile
RS Type-II mode, there is no need to have these contexts transfer, MRS needs to inform the target MRBS the local CID information

If optimized HO is supported, then only small amount of saving is achieved. However, in the case of
HO, such context transfer is not possible. In the case of multiple hop scenarios, the baseline proposal
needs to handle CID mapping on each intermediate RS to avoid the potential CID collision. The
proposed solution is independent of number of hops.

In addition, if the multiple tunnels are used to handle QoS, then we need to do CID mapping is
performed to each tunnel; therefore the handoff procedure will be applied for each tunnel.

For mobile RS, data encryption is done separately between BS and MRS, MRS---MS. The multiple MCPDU will be concatenated and transferred over the MR-BS---RS link. Encryption adds 22 bytes extra
overhead, if we concatenate 10 MAC PDU, then 220 bytes of overhead need to be transferred over the
MR-BS-MRS link, if the per-link encryption is used, only 22 bytes overhead are required to be
transferred over MR-BS --- MRS. This saving is significant.
3 Proposal
The key benefits of this operation mode of moving RS are to reduce the complexity caused by handover of a
moving RS and all of associated MSs, to reduce encryption overhead of MS traffic and message forwarding and
to eliminate the unnecessary MS unicast messages forwarding (RS can locally process most of unicast message).
In order to enable this operation, the connections between MR-BS and the moving RS is managed by MR-BS.
The connections of MSs associated with a RS mobile RS Type-II are managed by the RS and informed to the
MR-BS.
3.1 MR-BS CPS sub-layer function
When a MR-BS works with an access mobile RS Type-II, at each service flow setup, MR-BS establishes a
binding between the SFID, L-CID and forwarding connection identity T-CID. The upper layer header
suppression, if implemented, is performed on an end-to-end basis.
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IEEE C802.16j-07/432r3
For DL traffic forwarding, for each of received upper layer packets, the classification in CPS on the R-link
results in an output {T-CID, L-CID}. The tuple {SDU, T-CID and L-CID} shall be then provided to CPS sublayer through the SAP. For UL, when a short-version of MAC PDU is received by the CPS sub-layer in R-link
of MR-BS, the CPS sub-layer shall send tuple {SDU, T-CID, L-CID} to the CS sub-layer.
The CS sub-layer uses T-CID and L-CID to perform the de-suppression. The resulting packet then is delivered
to the upper layer.
3.2 RS CPS sub-layer function
For DL traffic forward, when a short-version MAC PDU is received by CPS sub-layer on R-link of an access
mobile RS Type-II, the CPS sub-layer on R-link shall send the tuple {SDU, L-CID} to the CS sub-layer. CS
sub-layer shall simply provide the tuple to the CS sub-layer on access like where the SDU is delivered to CPS
sub-layer on access link of the RS with the CID identified by L-CID. The CPS sub-layer then creates MAC PDU
to be delivered to MS.
For UL data forwarding, when a MAC PUD is received on access link of an access mobile RS Type-II, the
MAC PDU is delivered to the CS sub-layer with the CID. The SDU and CID are simply sent to the CPS sublayer on R-link of this RS. The CPS sub-layer then creates a short-version of MAC PDU and sends the shortversion MPDU to R-MAC sub-layer for forwarding purpose.
4. Proposed text change
[Add the following section 5.3 CS functions supporting access RS in moving BS mode]
+++++++++++++ Start text +++++++++++++++++++++++++++++++++++++++++++++++++
5.2.3 CPS sub-layer function supporting access mobile RS Type-II
5.2.3.1. MR-BS CPS sub-layer function supporting access mobile RS Type-II
When a MR-BS connects with an access mobile RS Type-II, at each service flow setup, MR-BS establishes a
binding between the SFID, L-CID and forwarding connection identity T-CID. The upper layer header
suppression, if implemented, is performed on an end-to-end basis.
For DL traffic forwarding, for each of received upper layer packets, the classification in CPS on the R-link
results in an output {T-CID, L-CID}. The tuple {SDU, T-CID and L-CID} shall be then provided to CPS sublayer through the SAP. For UL, when a short-version of MAC PDU is received by the CPS sub-layer in R-link
of MR-BS, the CPS sub-layer shall send tuple {SDU, T-CID, L-CID} to the CS sub-layer.
The CS sub-layer uses T-CID and L-CID to perform the de-suppression. The resulting packet then is delivered
to the upper layer.
5.2.3.2 CS sub-layer function supporting access mobile RS Type-II
For DL traffic forward, when a short-version MAC PDU is received by CPS sub-layer on R-link of an access
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IEEE C802.16j-07/432r3
mobile RS Type-II, the CPS sub-layer on R-link shall send the tuple {SDU, L-CID} to the CS sub-layer. CS
sub-layer shall simply provide the tuple to the CS sub-layer on access like where the SDU is delivered to CPS
sub-layer on access link of the RS with the CID identified by L-CID. The CPS sub-layer then creates MAC PDU
to be delivered to MS.
For UL data forwarding, when a MAC PUD is received on access link of an access mobile RS Type-II, the
MAC PDU is delivered to the CS sub-layer with the CID. The SDU and CID are simply sent to the CPS sublayer on R-link of this RS. The CPS sub-layer then creates a short-version of MAC PDU and sends the shortversion MPDU to R-MAC sub-layer for forwarding purpose.
+++++++++++++ end text +++++++++++++++++++++++++++++++++++++++++++++++++
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