1. Review of Multi-user Wakeup Schemes
Month Year
doc.: IEEE yy/xxxxr0
May 2017
Review of Multi-user Wakeup Schemes
Date:
Authors:
Name
Affiliation
Address
Phone
Yong CHENG
Huawei Device
Tian An Cloud Park, Bantian, Longgang, Shenzhen, , P.R. China.
Ping FANG
Yunsong YANG
Yong CHENG, et. al., Huawei Device
John Doe, Some Company

2. May 2017
Abstract
TGba has passed the Motion that “802.11ba spec shall define a mechanism to wake up multiple WUR mode STAs (e.g., multi-user wake-up frame)”, but a multi-user wakeup mechanism has not been defined yet. This contribution presents six multi-user wakeup schemes, and pros and cons of each scheme, so to help TGba to choose one or more multi-user wakeup schemes.
Yong CHENG, et. al., Huawei Device

3. May 2017
Background
TGba January F2F meeting passed the following motion [1, 2] regarding multi-user wakeup, but a specific multi-user wakeup scheme has not been defined yet.
[1] ba-meeting-minutes-march-2017.docx
[2] ba-wur-mac-issus
Yong CHENG, et. al., Huawei Device

4. Multi-user Wakeup Schemes
May 2017
Multi-user Wakeup Schemes
In the following slides, six multi-user wakeup schemes are discussed, along with their pros and cons:
Opt1: Send a WUP carrying multiple unicast WUR IDs
Opt2: Send TIM in a WUP
Opt3: Group STAs and send group TIM in the first WUP, and send (multiple) short TIM in the second WUP
Opt4: Group STAs and send a group-addressed WUP, and send full TIM in a Wi-Fi frame
Opt5: Send multiple unicast WUPs using OFDMA
Opt6: Group STAs and send group-cast/multi-cast WUPs using OFDMA
Yong CHENG, et. al., Huawei Device

5. Opt1: WUP with Multiple Unicast WUR IDs
May 2017
Opt1: WUP with Multiple Unicast WUR IDs
AP sends a WUP carrying multiple unicast WUR IDs to simultaneously wake up multiple STAs, similar as shown in [1].
Pros:
It can specify the target STAs that need to be woken up. It will not wake up the unintended STAs.
Cons:
WUP may become too long to transmit, e.g., with a TX rate of 125 kbps [2].
WUP (WUR ID 1, WUR ID 2, WUR ID 3) AP
STA1
STA2
STA3
STA4
Main radio on
DL Data (STA 1, 2, 3)
PS-Polls from STA 1~3
[1] ba-on-waking-up-of-multiple-wur-stations
[2] ba-wur-modulation-and-coding
Yong CHENG, et. al., Huawei Device

6. Opt2: Send TIM Info with WUP
May 2017
Opt2: Send TIM Info with WUP
AP sends TIM in WUP to simultaneously wake up multiple STAs [1].
Pros:
It can specify the target STAs that need to be woken up. It will not wake up the unintended STAs.
Cons:
TIM info may take too much time to send, e.g., with a TX rate of 125 kbps [2].
Longest TIM: 2048 bits; shortest TIM: 48 bits [ ]
WUP (TIM : STA1, STA2, STA3) AP
STA1
STA2
STA3
STA4
Main radio on
MU PPDU (STA 1, 2, 3)
PS-Polls from STA 1~3
[1] ba-wur-mac-issus
[2] ba-wur-modulation-and-coding
Yong CHENG, et. al., Huawei Device

7. Opt3: Group TIM and Short TIM
May 2017
Opt3: Group TIM and Short TIM
STAs are partitioned into multiple groups: G1, G2, …, Gn.
AP sends group TIM in WUP in the first step, followed by one or multiple WUPs carrying the short TIM per group in the second step.
Group TIM: TIM information with respect to groups
Short TIM: TIM information with respect to the STAs in one group
Pros:
TIM information is hierarchically arranged and much shorter.
It can be used to wake up all STAs in one or more groups.
Cons:
AP needs to send two WUPs.
For a target STA, the STA needs to receive the first and the second WUPs correctly. 1 G1 G2 G3 G4 Gn
Group TIM in WUP in the first step …
Short TIM of Group 2
Short TIM of Group 4
STA 2
STA 7
STA 13
(Multiple) WUPs carrying short TIM in the second step
[1] ba-initial-thoughts-on-mac-procedures
Yong CHENG, et. al., Huawei Device

8. Opt4: Group-Addressed WUP and Wi-Fi TIM Frame
May 2017
Opt4: Group-Addressed WUP and Wi-Fi TIM Frame
STAs are partitioned into multiple groups: G1, G2, …, Gn.
AP sends a group-addressed WUP, followed by a Wi-Fi TIM frame.
Broadcast WUP to wake up all STAs), or Group-cast WUP (WUP with group IDs, or WUP with group TIMs) to wakeup up multiple STAs
Wi-Fi TIM frame: Wi-Fi Beacon, or Public Action Frame carrying TIM info
Pros:
WUP is simple and short. AP sends one group-addressed WUP.
Cons:
Unintended STAs may be woken up by the group-addressed WUP.
Broadcast (or Group-cast) WUP AP
STA1
STA2
STA3
STA4
Wi-Fi TIM frame (TIM: STA1, STA2, STA4)
Main radio on
Main radio enters sleep
Yong CHENG, et. al., Huawei Device

9. Opt5: Send Multiple Unicast WUPs via OFDMA
May 2017
Opt5: Send Multiple Unicast WUPs via OFDMA
AP assigns different WUR channels to different STAs, e.g., a 4 MHz WUR channel within a 20 MHz Wi-Fi channel.
AP employs OFDMA to multiplex multiple unicast WUPs, each unicast WUP is intended for a target WUR/STA, e.g., multiplexing 6 WUPs in a 40 MHz Wi-Fi channel [1].
Pros:
Multiple unicast WUPs are sent out simultaneously, and it will not wake up unintended STAs.
Cons:
AP needs to manage the allocation of different WUR channels to different STAs, and it is not suitable to multiplex a large number of unicast WUPs in a limited BW.
L-STF
WUP for STA7
L-LTF
L-SIG
WUP for STA4
WUP for STA8
WUP for STA2
WUP for STA6
WUP for STA5
4 MHz WUR channel
2 MHz guard band
40 MHz channel
[1] ba-concurrent-transmission-of-data-and-a-wake-up-signal-in ax-follow-up
[2] ba-on-waking-up-of-multiple-wur-stations
Yong CHENG, et. al., Huawei Device

10. Opt6: Send Group-cast WUPs with OFDMA
May 2017
Opt6: Send Group-cast WUPs with OFDMA
STAs may be partitioned into multiple groups: G1, G2, …, Gn.
AP assigns different WUR channels to different groups/STAs.
AP employs OFDMA to multiplex multiple group-cast/multi-cast WUPs, e.g., multiplexing 6 group-cast/multi-cast WUPs in a 40 MHz Wi-Fi channel [1].
A multi-cast WUP may carry a group ID (group-cast) or multiple unicast WUR IDs (multi-cast).
Pros:
Multiple group-cast WUPs are sent out simultaneously to wake up multiple STAs.
Cons:
AP needs to manage the allocation of different WUR channels for different groups/STAs and the grouping of STAs.
L-STF
Group-cast WUP for Group7
L-LTF
L-SIG
Group-cast WUP for Group4
Group-cast WUP for Group8
Group-cast WUP for Group2
Group-cast WUP for Group6
Group-cast WUP for Group5
4 MHz WUR channel
2 MHz guard band
40 MHz channel
Yong CHENG, et. al., Huawei Device