Enhancing PS-poll for low-power WiFi

1. A method, comprising:

obtaining, by a network controller, a group-addressed packet destined for multiple subscriber stations (SSs) belonging to a group to receive the group-addressed packet;

determining that a particular SS in the group is currently unable to receive group-addressed packets due to being in a sleep mode;

transmitting the group-addressed packet to the multiple SSs belonging to the group to receive the group-addressed packet when the particular SS in the group to receive the group-addressed packet is in the sleep mode;

retaining, by the network controller, the group-addressed packet in a buffer;

receiving a poll from the particular SS; and

retransmitting the group-addressed packet in response to said receiving the poll.

2. The method of claim 1 , further comprising transmitting, prior to said determining, a notification that the network controller supports said retaining and retransmitting group-addressed packets.

3. The method of claim 2 , wherein the notification is contained in a field of a QoS Compatibility information element.

4. The method of claim 1 , further comprising receiving from the particular SS, prior to said determining, a notification that the particular SS supports polling for group-addressed packets.

5. The method of claim 4 , wherein the notification is contained in a field of a Low Power Capability information element.

6. A network controller device for communicating in a wireless communications network, the device having a processor, a memory, and a radio, the network controller device to:

obtain a group-addressed packet destined for multiple subscriber stations (SSs) belonging to a group to receive the group-addressed packet;

determine that a particular SS in the group is currently unable to receive group-addressed packets due to being in a sleep mode;

transmit the group-addressed packet to the multiple SSs belonging to the group to receive the group-addressed packet when the particular SS in the group to receive the group-addressed packet is in the sleep mode;

retain the group-addressed packet in a buffer;

receive a poll from the particular SS; and

retransmit the group-addressed packet in response to said receiving the poll.

7. The device of claim 6 , the network controller device to transmit, prior to said determining, a notification that the device supports said retaining and retransmitting group-addressed packets.

8. The device of claim 7 , wherein the notification is to be contained in a field of a QoS Compatibility information element.

9. The device of claim 6 , the network controller device to receive from the particular SS, prior to said determining, a notification that the particular SS supports polling for group-addressed packets.

10. The device of claim 9 , wherein the notification is to be contained in a field of a Low Power Capability information element.

11. A computer-readable non-transitory storage medium that contains instructions, which when executed by one or more processors result in performing operations comprising:

obtaining, by a network controller, a group-addressed packet destined for multiple subscriber stations (SSs) belonging to a group to receive the group-addressed packet;

determining that a particular SS in the group is currently unable to receive group-addressed packets due to being in a sleep mode;

transmitting the group-addressed packet to the multiple SSs belonging to the group to receive the group-addressed packet when the particular SS in the group to receive the group-addressed packet is in the sleep mode;

retaining, by the network controller, the group-addressed packet in a buffer;

receiving a poll from the particular SS; and

retransmitting the group-addressed packet in response to said receiving the poll.

12. The medium of claim 11 , wherein the operations further comprise transmitting, prior to said determining, a notification that the network controller supports said retaining and retransmitting group-addressed packets.

13. The medium of claim 12 , wherein the notification is contained in a field of a QoS Compatibility information element.

14. The medium of claim 11 , wherein the operations further comprise receiving from the particular SS, prior to said determining, a notification that the particular SS supports polling for group-addressed packets.

15. The medium of claim 14 , wherein the notification is contained in a field of a Low Power Capability information element.

16. A method of communicating by a device in a wireless communications network, comprising:

entering a sleep mode;

waking from the sleep mode;

transmitting a poll to a network controller requesting buffered packets; and

receiving the buffered packets in response to the poll;

wherein at least one of the buffered packets is a group-addressed packet retransmitted subsequent to waking from the sleep mode and previously transmitted to other devices when the device was in the sleep mode; receiving from the network controller, prior to said entering, a notification that the network controller supports retaining and retransmitting group-addressed packets.

17. The method of claim 16 , wherein the notification is contained in a field of a QoS Compatibility information element.

18. The method of claim 16 , further comprising transmitting to the network controller, prior to said entering, a notification that the device supports polling for group-addressed packets.

19. The method of claim 18 , wherein the notification is contained in a field of a Low Power Capability information element.

20. A wireless communications device having a processor, a memory, and a radio, the wireless communications device to:

enter a sleep mode;

wake from the sleep mode;

transmit a poll to a network controller requesting buffered packets; and

receive the buffered packets in response to the poll;

wherein at least one of the buffered packets is to be a group-addressed packet retransmitted subsequent to the wireless communications device waking from the sleep mode and previously transmitted to other devices when the wireless communications device was in the sleep mode; the wireless communications device to receive from the network controller, prior to said entering, a notification that the network controller supports retaining and retransmitting group-addressed packets.

21. The method of claim 20 , wherein the notification is to be contained in a field of a QoS Compatibility information element.

22. The device of claim 20 , the wireless communications device to transmit to the network controller, prior to said entering, a notification that the device supports polling for group-addressed packets.

23. The device of claim 22 , wherein the notification is to be contained in a field of a Low Power Capability information element.

24. A computer-readable non-transitory storage medium that contains instructions, which when executed by one or more processors result in performing operations comprising:

entering a sleep mode;

waking from the sleep mode;

transmitting a poll to a network controller requesting buffered packets; and

receiving the buffered packets in response to the poll;

wherein at least one of the buffered packets is a group-addressed packet retransmitted subsequent to waking from the sleep mode and previously transmitted to other devices when the device was in the sleep mode and previously transmitted to other devices when the one or more processors were in the sleep mode; wherein the operations further comprise receiving from the network controller, prior to said entering, a notification that the network controller supports retaining and retransmitting group-addressed packets.

25. The method of claim 24 , wherein the notification is contained in a field of a QoS Compatibility information element.

26. The medium of claim 24 , wherein the operations further comprise transmitting to the network controller, prior to said entering, a notification that the device supports polling for group-addressed packets.

27. The medium of claim 26 , wherein the notification is contained in a field of a Low Power Capability information element.