IEEE C802.16n-11/NNNN
Project
IEEE 802.16 Broadband Wireless Access Working Group <http://ieee802.org/16>
Title
Support of Local Forwarding for the IEEE 802.16n Networks
Date
Submitted
2011-03-06
Source(s)
Shoukang Zheng, Haiguang Wang,
Choong Hock Mar, Jaya Shankar, Hoang
Anh Tuan, Yeow Wai Leong and Joseph
Chee Ming Teo
Voice: +65 6408-2252
E-mail: skzheng@i2r.a-star.edu.sg
Institute for Infocomm Research
1 Fusionopolis Way, #21-01, Connexis
(South Tower)
Singapore 138632
Re:
Call for contributions for 802.16n AWD
Abstract
In this document, we propose an approach to support local forwarding for IEEE 802.16n network
for more efficient communication
Purpose
To discuss and adopt the proposed text in the 802.16n draft Text
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.
Notice
Copyright
Policy
Patent
Policy
The contributor is familiar with the IEEE-SA Copyright Policy
<http://standards.ieee.org/IPR/copyrightpolicy.html>.
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>.
Support of Local Forwarding for the IEEE 802.16n Networks
Shoukang Zheng, Haiguang Wang, Choong Hock Mar, Jaya Shankar, Hoang Anh Tuan, Yeow Wai
Leong and Joseph Chee Ming Teo
Institute for Infocomm Research (I2R)
1 Fusionopolis Way, #21-01, Connexis South Tower
Singapore 138632
1
IEEE C802.16n-11/NNNN
1. Introduction
The SRD in 802.16n requires that HR-Network should allow local forwarding, which allows one HR-MS to
communicate to one or more HR-MSs via infrastructure station without going through the backhaul. Comparing
to data transfer between a BS and MS, local forwarding is more efficient to allow the data forwarding done by
the relay station without going through BS or the backhaul. In this document, we propose an RS-initiated
method to support local forwarding for unicast flow. We assume that the IEEE 802.16n amendment will be an
extension of the IEEE 802.16m amendment.
2. Proposed protocol
An example of local forwarding for unicast flows is shown as in Fig. 1, where two HR-MSs starts
communication via infrastructure stations HR-RS and HR-BS in the left figure and via HR-RS performing local
forwarding in the right figure. In Fig. 1, the solid line indicates the links between the stations and the dash line
represents the data path. Obviously the link bandwidth between HR-RS and HR-BS could be saved to improve
the efficiency when local forwarding is performed by HR-RS.
HR-BS
3
3
2
HR-BS
HR-RS
1
HR-MS
HR-MS
2
HR-MS
4
1
HR-RS
HR-MS
Fig. 1 Communication path for 802.16m networks without local forwarding (left figure)
and 802.16n networks with local forwarding (right figure)
We propose an RS-initiated method that can detect the local forwarding opportunity by HR-RS. During network
entry and initialization, HR-MS is assigned with IP address and station ID (STID), which is known to HR-RS.
When the source HR-MS starts to communicate with the destination HR-MS, control messages (e.g. DSA-REQ)
including source and destination IP addresses will be received by HR-RS if both HR-MSs are associated with
the same HR-RS. Hence once the FIDs for uplink flow from the source to HR-RS and downlink flow from HRRS to the destination are assigned by HR-RS, a binding of these two FIDs (or equivalently station flow IDs i.e.
SFIDs) can be done through HR-RS maintaining a table of IP address and STID of HR-MSs, which is
established during registration and connection establishment. The procedure of control messages and data flow
for local forwarding can be shown as in Fig. 2, where HR-MS1 is the source and HR-MS2 is the destination.
2
IEEE C802.16n-11/NNNN
HR-MS1
Src
HR-MS2
Dst
HR-RS
HR-BS
DSA-REQ
RS detects local forwarding opportunity
Get permission from HR-BS
DSA-REQ
DSA-RSP
DSA-ACK
UL/DL SFID/FIDs binding
DSA-RSP
DSA-ACK
Local forwarding commences
data
data
data
.
.
.
Fig. 2 Control messages and data flow in RS-initiated local forwarding.
1. HR-MS1 sends DSA-REQ to HR-RS after classifying the flow to HR-MS2.
2. HR-RS receives DSA-REQ from HR-MS1 and HR-RS detects the local forwarding opportunity since
both HR-MS1 and HR-MS2 are under the control of the same relay station HR-RS.
3. HR-RS sends control messages to request for permission from HR-BS to perform local forwarding for
HR-MS1 and HR-MS2 and may optionally query HR-BS whether to establish the uplink from HR-RS to
HR-BS.
4. HR-BS allows HR-RS do local forwarding for HR-MS1, indicating that whether to establishment the
uplink flow.
5. HR-RS sends DSA-REQ to HR-MS2, assigning a FID to HR-RS for the downlink flow. HR-MS2
replies with DSA-RSP and HR-RS acknowledges with DSA-ACK. This completes the establishment of
downlink flow.
3
IEEE C802.16n-11/NNNN
6. HR-RS sends DSA-RSP to HR-MS1 and HR-RS replies with DSA-ACK. This completes the
establishment of uplink flow. HR-RS assigns uplink FID for HR-MS1.
7. HR-RS binds two FIDs together and can route data flow from HR-MS1 to HR-MS2 without going
through HR-BS.
8. HR-MS1 sends the data with the assigned FID to HR-RS. HR-RS forwards the received data from HRMS1 to HR-MS2 with respect to the binding and may send data from HR-MS1 to HR-BS if required.
In handover we consider two cases (i) when HR-MS (either the source or the destination) is going out of the
control of HR-RS that performs local forwarding for it, and (ii) when HR-MSs (both the source and the
destination) are going to be under the control of the same HR-RS that will perform local forwarding for
them. In first case, serving HR-RS has to relinquish the local forwarding as both are not under the same HRRS. This results in the connection re-establishment after handover same as the normal scenario without local
forwarding. In second case, the target HR-RS has to perform the connection re-establishment similar to the
procedure given in Fig. 2. The details are shown in the following figures (Fig.3-6) where Fig. 3 is the case
that source HR-MS is going out of the control of HR-RS that performs local forwarding for it, Fig. 4 is the
case that destination HR-MS is going out of the control of HR-RS that performs local forwarding for it,
Fig.5 is the case that source HR-MS is performing handover and is going to be under the control of same
HR-RS that performs local forwarding for both HR-MSs and Fig.6 is the case that destination HR-MS is
performing handover and is going to be under the control of same HR-RS that performs local forwarding for
both HR-MSs.
4
IEEE C802.16n-11/NNNN
2
1
HR-BS
TRS
HR-RS
1
2
1
HRMS1
HRMS2
Fig. 3 source HR-MS1 is going out of the control of HR-RS that performs local forwarding
HR-BS
1
2
HR-RS
TRS
1
2
2
HRMS1
HRMS2
Fig. 4 destination HR-MS2 is going out of the control of HR-RS that performs local forwarding
1
HR-BS
1
HRMS1
TRS
1
2
HR-RS
HRMS2
Fig. 5 source HR-MS1 is performing handover and is going to be under the control of same HR-RS that
performs local forwarding for both HR-MSs
5
IEEE C802.16n-11/NNNN
HR-BS
1
2
TRS
HR-RS
1
2
2
HRMS1
HRMS2
Fig.6 destination HR-MS2 is performing handover and is going to be under the control of same HR-RS that
performs local forwarding for both HR-MSs.
3. Text Proposal for IEEE 802.16n AWD
[-------------------------------------------------Start of Text Proposal---------------------------------------------------]
[Insert the following text into Section 17.2.6 Local Forwarding of the 802.16n Document (C802.16n-10/0049)]
HR-RS should detect the local forwarding opportunity and be able to bind together the uplink flow ID from the
source and the downlink flow ID to the destination for two communicating HR-MSs within its control during
connection establishment or connection re-establishment for handover, if it is allowed by HR-BS. After the
binding HR-RS is able to forward the data from the source to the destination without going through HR-BS and
may optionally forward to HR-BS one copy of the data that is being locally forwarded, if required.
[-------------------------------------------------End of Text Proposal----------------------------------------------------]
References
[1] IEEE 802.16n-10/0048, “802.16n System Requirements Document including SARM annex”, January 2011.
[2] IEEE 802.16n-10/0049, “802.16n Table of Contents for Amendment Working Draft”, January 2011.
6