IEEE C802.16n-11/0107r1
Project
IEEE 802.16 Broadband Wireless Access Working Group <http://ieee802.org/16>
Title
Support of Alternative Interface
Date
Submitted
2011-07-20
Source(s)
Ronald Mao, Erik Colban, Bin Chen
Huawei Technologies
Re:
Call for contributions for 802.16n AWD as announced on June 1, 2011
Abstract
This contribution provides specifications on using an alternative interface (Ralt), as required by
the SRD.
Purpose
To be adopted by 802.16n
Notice
Copyright
Policy
Patent
Policy
E-mail: rmao@huawei.com,
ecolban@huawei.com
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.
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 Alternative Interface
Ronald Mao, Erik Colban, Bin Chen
Huawei Technologies
Introduction
An alternative interface is an interface between two HR-MSs that is not on the IEEE 802.16 air interface. It may
be on an air interface on an unlicensed spectrum such as WLAN, or a wired interface on a power line.
In advanced metering such as Smart Grid, utility companies have requirements to have metering devices access
the network on scheduled time intervals for it is expected that under normal operations the majority of traffic
from/to the MS will be regular as opposed to being ad-hoc in nature. This deterministic type of behavior allows
for optimizing the operation of the HR-MS in that the HR-MS can be scheduled to enter or re-enter to the
network only at specific time instances and only for a limited period of time. Such time controlled operation
means better air interface utilization, reduced interference, conserved network resources, and possibly increased
battery life, etc. However, a limitation with time controlled operation is that, as the HR-MS is not monitoring
the air interface outside its pre-defined connection interval; the network cannot contact the MS outside of this
interval. This contribution proposes a solution to mitigate this problem by allowing the network to send a
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IEEE C802.16n-11/0107r1
connection notification to a target HR-MS via a neighboring HR-MS that is currently in connected state. The
neighboring HR-MS will relay the notification to the target HR-MS on the alternative interface. Upon receiving
the notification, the target HR-MS will enter the network to receive data from the network.
In the case where a HR-BS has data to be delivered to a target HR-MS, and the target HR-MS is powered off, or
in an extended sleep mode, and there there is an alternative interface between the target HR-MS and a
neighboring HR-MS, the HR-BS may request the neighboring HR-MS to relay a notification about the pending
data delivery over the alternative interface. This procedure is illustrated in Error! Reference source not found..
Figure 1: Activate a disconnected MS over alternative interface
As the figure illustrates, to deliver data to a target HR-MS (MS1) currently disconnected from the BS, the BS
sends a notification to the neighboring HR-MS (MS2), which in turn forwards such notification to the target MS
over the alternative connection. Upon receipt of this notification the target MS connects to the BS and receives
any pending messages from the HR-BS.
The alternative interface may be a wireless access connection that supports direct P2P communication over an
unlicensed spectrum or a wired connection over power lines. In either case, the MS monitors the alternative
interface. For security reasons, only a notification is forwarded from the BS to have the target HR-MS establish
a connection with the BS. The neighboring MS shall not relay actual data via the alternative connection.
The data delivery described here relies on the availability of an HR-MS in connected state and the existence of
an alternative interface between this HR-MS and the HR-MS for which the indication is to be sent. In the
absence of these conditions, the HR-BS will buffer the data until such period that either the target HR-MS is
connected to the network or neighboring HR-MS within reach of the desired MS enters into a connected state.
The HR-BS locates a relay HR-MS by sending a multicast message to the multicast group to which the target
HR-MS belongs. The delivery of the multicast message is guaranteed to reach the relaying MS in the
neighborhood of the target MS because scheduled access devices are stationary and the network topology does
not change. Hence the network is aware of the whereabouts of the devices even when they are currently not
accessing the network.
Proposed Text
17.3.5 Relaying operation
Relay operation described in Section 16.6 shall be supported.
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In order to provide great reliability in a degraded network, the relay function described in this subsection shall be
supported.
In order to support local forwarding in an HR-RS, the HR-RS shall follow operation as defined in Section 17.3.6.
17.3.5.x Relaying connection notifications over an alternative interface
An alternative interface is an interface between two stationary HR-MSs that is not an IEEE 802.16 air interface.
It may be an air interface on an unlicensed spectrum such as WLAN, or a wired interface on a power line.
When an HR-BS has downlink data for a HR-MS that has powered down or in an extended sleep mode from the
802.16 network, the HR-BS may send a multicast Connection Notification message to the multicast group to
which the target HR-MS belongs. In the multicast message, the identity of the target HR-MS is included. When
HR-MS in the multicast group that is currently connected to the network receives the notification, the HR-MS is
assumed to relay the notification to the target HR-MS identified in the Connection Notification message over
the alternative interface. Upon receipt of this notification, the target HR-MS shall enter the network and receive
any pending messages from the HR-BS.
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