1. 1MHz mode PHY based power savings
May 2012
doc.: IEEE /0614r0
May 2012
1MHz mode PHY based power savings
Date:
Authors:
Sudheer Grandhi, InterDigital Communications
Sudheer Grandhi, InterDigital Communications

2. May 2012
doc.: IEEE /0614r0
May 2012
Abstract
This document discusses possibility of power saving at PHY layer for 1MHz mode.
Sudheer Grandhi, InterDigital Communications
Sudheer Grandhi, InterDigital Communications

3. PHY Power Saving Issue in 1 MHz Mode
May 2012
PHY Power Saving Issue in 1 MHz Mode
In the SIGA field of >=2 MHz mode, a STA may use PAID field to achieve PHY layer power savings at the STA:
Partial Association Identifier (PAID) field: 9 bits
This allows a STA to determine that it is not the intended recipient of the packet when PAID does not match
a STA may choose to not decode the remainder of the PPDU for power saving
PAID is not present in the 1 MHz preamble SIG field [2]
a STA cannot determine whether it is the unintended recipient or not
i.e., a STA must always decode the entire PPDU
Therefore, the current 1MHz design does not offer the same PHY layer power savings as 2MHz and above
Sudheer Grandhi, InterDigital Communications

4. Proposal: Direction Indication Bit
May 2012
Proposal: Direction Indication Bit
One of the reserved bits in the SIG field of a 1 MHz mode may be defined to indicate whether the current packet is received from, or destined to the AP
A non-AP STA will check the direction indication bit (DIB) in the received SIG
If the DIB indicates that the packet is destined to the AP, then in this case the STA can sleep for the remaining duration of the packet
Sudheer Grandhi, InterDigital Communications

5. May 2012
Summary
The current 1MHz mode design does not allow PHY layer power saving as 2MHz and above modes
Proposal:
Use1 bit of reserved SIG bits of 1MHz mode to allow PHY layer power savings
Sudheer Grandhi, InterDigital Communications

6. Questions / Comments ? Thank You!
May 2012
doc.: IEEE /0614r0
May 2012
Questions / Comments ?
Thank You!
Sudheer Grandhi, InterDigital Communications
Sudheer Grandhi, InterDigital Communications

7. May 2012
Straw Poll 1
Do you think that Direction indication bit of 1MHz format should be further studied to allow power savings at the receiver/STA?
Yes No
Abstain
Sudheer Grandhi, InterDigital Communications

8. May 2012
doc.: IEEE /0614r0
May 2012
References
[1] IEEE Std ™-2012: Wireless LAN MAC and PHY Specifications
[2] IEEE /1482r4, “Preamble Format for 1 MHz,” Qualcomm and et. al.
[3] IEEE /0119r0, “Early ACK Indication,” Marvell and et. al.
Sudheer Grandhi, InterDigital Communications
Sudheer Grandhi, InterDigital Communications