IEEE C802.16m- 09/2836
Project
IEEE 802.16 Broadband Wireless Access Working Group <http://ieee802.org/16>
Title
Proposal to clarify the low-duty mode for femto ABS (16.4)
Date
Submitted
2009-12-30
Source(s)
Mihyun Lee, Hokyu Choi
mihyun.mac.lee@samsung.com
Samsung Electronics Co., Ltd.
Re:
IEEE 802.16-09/0073, “IEEE 802.16 Working Group Letter Ballot#30b”
Target topic: “IEEE P802.16m/D3, section 16.4”.
Abstract
The contribution proposes to clarify the low-duty operation mode for femto ABS.
Purpose
To be discussed and adopted by TGm for the 802.16m/D4
Notice
Release
Patent
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IEEE C802.16m- 09/2836
Proposal to clarify the low-duty mode for femto ABS (16.4)
Mihyun Lee, Hokyu Choi
Samsung Electronics
1. Introduction
In D3 text, the low duty mode for femto ABS consists of available interval and unavailable interval in unit of
superframe. The femto ABS during unavailable interval does not transmit any signal on air interface. However,
if a femto ABS doesn’t tranmsit its identification information and ranging information during certain time, AMS
is hard to identify the existence of any femto ABSs during unavailable interval when an AMS may scan femto
ABSs that are not included in AAI_NBR-ADV message. Besides, a AMS tries to access less appropriate ABS as
a target ABS even though the femto ABS during unavailable interval is proper. It is hard to predetermine the
default LDM patterns because femto ABSs may have inactive AMS having different paging or sleep cycle.
Data
Common Pilots
A-MAP
Data
Preamble
Data
Common Pilots
A-MAP
Preamble
Preamble
SFH Common Pilots
A-MAP
Preamble
This contribution proposes that femto ABS during low duty mode transmits A-Preambles and SFH to be
acquired its identification information and ranging information by AMS. Figure 1 shows the example of
proposed low duty mode of femto ABS.
Common Pilots
A-MAP
Data
superframe
Normal mode
Normal mode
Preamble
Preamble
Preamble
SFH
Preamble
Low duty mode
Figure 1. Example of low duty mode of femto ABS
In Addition, current texts were mixed up in low-duty mode and low-duty operation mode. I suggest using the
low-duty mode which was specified in section 4[1]
2. References
[1] IEEE P802.16m/D3, “P802.16m DRAFT Amendment to IEEE Standard for Local and metropolitan area
networks Part 16: Air Interface for Broadband Wireless Access Systems”, 2009-12-08
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3. Proposed Text Changes
[Remedy #1: Modify the text in page 594, line 45, section 16.4.3 as follows],
16.4.3 Femto ABS State Diagram
A Femto ABS transitions through multiple states during its operation, as illustrated in Error! Reference source not
found.. On Power-On, it enters the Initialization State. In this state, procedures like configuration of radio interface
parameters and time/frequency synchronization should be performed. After attachment to service provider's core
network, which may include synchronization to the Macro ABS, it enters the Operational State. In the Operational State,
if the Femto ABS becomes unattached to the service providers network or if it fails to meet operational requirements
(may include failed synchronization), it reverts to the Initialization State.
In the Operational State, normal and low-duty operation modes are supported. In low-duty mode, the Femto ABS
reduces radio interface activity in order to reduce interference to neighbor cells. In the low duty mode, the Femto ABS
will alternate between available and unavailable interval (i.e., low-duty operation cycle). A further functional
description of low-duty operation mode of Femto ABS is specified can be found in Error! Reference source not
found..
An AMS shall connect to a Femto ABS only in Operational State.
<Note for Editor: Delete the red strikeouts (boxes, arrows and texts) in figure 573.>
Power On/Off
Operational State
Normal Operation mode
Initialization
State
Low-duty mode
Available
Interval
Unavailable
Interval
Figure 573—Functional overview of Femto ABS states and operational modes
[Remedy #2 Modify the text in page 602, line 54, section 16.4.10 as follows,]
16.4.10 Low-duty Operation Mode
16.4.10.1 General description
Besides the normal operation mode, Femto ABSs may support low-duty operation mode, in order to reduce interference
to neighbor cells.
The low-duty operation mode consists of available intervals (AI) and unavailable intervals (UAI). During an available
interval, the Femto ABSs may become active on the air interface for activities such as paging, transmitting system
information, ranging or for data traffic transmission. During an unavailable interval, it does not transmit on the air
interface. Unavailable interval may be used for synchronization with the overlay macro BS or measuring the
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IEEE C802.16m- 09/2836
interference from neighbor cells.
The Femto ABS during low-duty mode shall transmit Advanced preambles and the first subframe carrying SFH.
However, the Femto ABS during low-duty mode may not transmit any other signals.
The Femto ABS may enter low-duty operation mode either if no MS is active and keep low-duty mode if no MS tries to
access it. all MSs attached to the Femto ABS are in idle or sleep mode, and if no AMS is in the process of network
entry
The operational state field carried in P-SFH IE indicates whether the operation state of Femto ABS is low-duty mode or
normal mode.
15.4.10.2 Default LDM pattern(s)
A Sequence of availability and unavailability intervals forms an LDM pattern. The Default LDM pattern is the iteration
of one available interval and one unavailable interval. An available interval for Default LDM pattern begins with the
frame including the PA-Preamble. The Default LDM pattern is a subset of the available intervals at the femto ABS.
The Default LDM pattern parameters include:
–Available interval (in units of four frames)
–Unavailable interval (in units of four frames)
- Start superframe number
Once a femto ABS enters low duty mode, the Default LDM pattern of the femto ABS may be activated.
There may be one or more default LDM patterns in a femto ABS deployment. The Default LDM pattern(s) parameters
can be pre-provisioned or unicasted to the AMS during initial network entry with the femto ABS in the AAI_REG-RSP
message.
[Remedy #3Add the following parameter into Table 799 in page375, section 16.3.6.5.1.1 as follows,]
Table 799—P-SFH IE format
Syntax
Size (bit)
Notes
P-SFH IE format () {
…….
Operational state
1
Indicate the operational state of femto ABS
0b0: Normal mode
0b1: Low-duty mode
}
4