Power Saving Considerations for IEEE 802.16m Femtocell
IEEE 802.16 Presentation Submission Template (Rev. 9)
Document Number:
IEEE C802.16m-08/1411r1
Date Submitted:
2008-10-31
Source:
Ming-Hung Tao, Mamadou Kone, Ying-Chuan Hsiao, Richard Li
ITRI
E-mail: mhtao@itri.org.tw
Venue:
TGm call for contributions on IEEE 802.16m-08/040. Specific topic : “Support for Femtocells”
Base Contribution:
N/A
Purpose:
To be discussed and adopted by TGm.
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1
Micro-sleep in femtocell
• Time zones
– Because a femtocell supports only few MSs (no
more than 10), the superframe in femtocell can be
divided into several time zones, each zone can be
either dedicated to a specific MS or public to all
MSs.
– MSs in active mode knows the distribution of time
zones from the SFH, and monitor only its
dedicated zones and public zones.
– A time zone is composed by one or multiple subframes.
2
Time zones in femtocell
Super-frame
Public
B
A
C
B
A
C
Public
SFH
A
Dedicated to MS A
C
Dedicated to MS C
B
Dedicated to MS B
Public Public to all MSs
3
Sleep mode in femtocell
• Sleep mode procedure (including timer,
signaling) in femtocell is the same as in
macrocell.
• During the MS listening interval/window, an
MS first knows the zone distribution
information from SFH, then checks the traffic
indication from BS or transmits its data to BS
only in its dedicated zones or public zones.
4
Idle mode in femtocell (cont.)
• The femto BS maintains a paging group ID which is
different from the PG ID of the macro BS, this PG ID
may be shared by multiple femto BSs that have the
same access set.
• The paging message for an MS staying in a femto BS
is broadcast to the femtocells in the same group only.
• When an idle-mode MS moves from femtocells to
macrocells or from marcocells to femtocells, it will
observe a different PG ID and perform location
update.
• During paging listening interval, an idle-mode MS
monitors only the public time zone for the paging
message.
5
Idle mode in femtocell (cont.)
• In femtocell, shall we count idle-mode MSs as
normal MSs when considering cell capacity?
– If yes, the resource utilization will be low.
– If no, the femto BS shall notify the existed idlemode MSs that the maximum capacity is reached
when it happens, as well as notify the new idlemode MS who is coming from other femtocell or
marcocell.
6
Idle mode in femtocell (cont.)
A femtocell with capacity = 5 MSs
Idle-mode MS
Active-mode MS
New coming idle-mode MS
Full notification
The notification can be done through either location update or paging messages
7
Proposed text for SDD
17 Support for Femtocell
17.x Frame structure in femtocell
The superframe in femtocells can be divided into several time
zone, each zone can be either dedicated to a specific MS or
public to all MSs. A time zone is composed by one or multiple
subframes. The zone distribution information should be
carried within SFH.
17.y Idle mode in femtocell
When considering the capacity of a femtocell, idle-mode MSs
should not be counted into the number of MSs. The femtocell
should be able to notify idle-mode MSs that the maximum
capacity is reached if it happens.
8