Transcript Slides S802.16m-07/220

An addition to the legacy frame structure to save BS power during periods of low traffic
IEEE 802.16 Presentation Submission Template (Rev. 9)
Document Number:
IEEE S802.16m-07/220
Date Submitted:
2007-11-14
Source:
Stefan Lindgren, Sten Sjoberg
Ericsson AB
E-mail:
[email protected]
Venue:
IEEE 802.16m-07/040 - Call for Contributions on Project 802.16m System Description Document
Base Contribution:
IEEE C802.16m-07/220
Purpose:
Inclusion of a section on generic frame structure in a Physical Layer chapter of the 802.16m SDD. The generic frame structure section
should in addition to a basic description of, or reference to, the legacy frame structure include proposed 802.16m additions including the
proposal in this document.
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.
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Introduction
• Minimizing the energy consumption in
telecommunication systems has become very
important to reduce operating cost and to protect the
environment. Network operators are increasingly
aware of the energy efficiency of their networks.
• An addition to the legacy frame structure is proposed
to enable power saving in a base station during
periods of low traffic, e.g. night time, by using a
concept similar to sleep mode of mobile stations.
Proposal
• It is suggested that the Physical Layer is a chapter of
the SDD and that the generic frame structure is
described as a subsection of the Physical Layer
chapter
• After a description of the legacy WirelessMANOFDMA Reference System frame structure with
Figure 273 from the 802.16 standard (Rev2/D1) or
suitable references to the 802.16 standard, additions
to the legacy frame structure should be described
Requirement basis
• Section 6.11 of the 802.16m System
Requirements Document (SRD) requires
support for enhanced power saving which
should apply to the access network devices as
well.
• Section 8.4 of the SRD asks for selfoptimization for optimization of network
efficiency.
Frame sequences
Frame #N
Frame #N+1
Frame #N+2
Frame #N+3
Frame #N+4
Frame #N+5
A Legacy frame sequence. The Frame Number is a 24-bit number given as a part of the OFDMA PHY Synchronization field in
the DL-MAP.
Frame
#N-1
Frame
#N
Gap x frames
long………….
Frame
#N+1+x
Frame
#N+2+x
Gap x frames
long…………
Frame
#N+3+2x
A Power saving mode frame sequence. The example shows a pattern of two frames followed by a gap of x frames.
Announce the gap in the frame sequence
• Alternative1: Use the Frame Duration Code
(unused bits in the Legacy System)
in the DL-MAP
• Alternative 2: Define a new Frame Gap IE in
the DL-MAP
Announce the periodic on-off pattern
• The Downlink Channel Descriptor (DCD)
should announce the periodic on-off pattern
used at the BS in a new TLV and the same
TLV could be used in the MOB_NBR-ADV
message to announce the on-off patterns of
neighboring BSs.
Handling of legacy MS
• Legacy MS that cannot read the protocol
additions can be handled by assigning them a
sleep mode pattern that is synchronized with
the BS on-off pattern.
There should be a limit on the length of the
frame gaps to ensure initial network discovery
within a reasonable time.
Proposed SDD Text
• [Chapter] Physical Layer
• …………..
• [Section] Frame Structure
• [A short description of the legacy WirelessMAN-OFDMA Reference
System frame structure with Figure 273 from the 802.16 (Rev2/D1)
standard or suitable references to the 802.16 standard]
• The BS may choose to allocate and announce gaps in the sequence of
frames, typically in a periodic pattern. The Frame Number counter is
incremented as if frames were transmitted in a non-interrupted
sequence.
• [Other additions]
• ……………….