Uplink multi-user multiple input multiple output beamforming

1. A method, comprising:

prompting, at a first communication device, a plurality of second communication devices to transmit, to the first communication device, respective beamforming training packets as part of a procedure for developing respective transmit beamforming matrices for use by the plurality of second communication devices;

receiving, at the first communication device, the respective beamforming training packets as part of the procedure for developing the respective transmit beamforming matrices, the respective beamforming training packets having been transmitted by the plurality of second communication devices in response to the prompting;

generating, at the first communication device, respective beamforming feedback packets based on reception of the respective beamforming training packets;

transmitting, from the first communication device, the respective beamforming feedback packets as part of the procedure for developing the respective transmit beamforming matrices;

selecting, at the first communication device, a group of multiple second communication devices from among the plurality of second communication devices using channel information developed based on reception of the respective beamforming training packets, the group selected for simultaneous transmissions to the first communication device;

transmitting, with the first communication device, a synchronization signal to the group to prompt second communication devices in the group to simultaneously transmit to the first communication device at a particular time; and

receiving, with the first communication device, simultaneous transmissions from the group responsive to the synchronization signal, the simultaneous transmissions having been beamformed by second communication devices in the group using transmit beamforming matrices developed by the second communication devices in the group as part of the procedure for developing respective transmit beamforming matrices for use by the plurality of second communication devices.

2. The method of claim 1 , wherein each beamforming training packet is a null data packet (NDP).

3. The method of claim 1 , wherein:

the first communication device is an access point; and

the plurality of second communication devices are stations associated with the access point.

4. The method of claim 1 , wherein the group is selected for multi-user (MU) multiple input, multiple output (MIMO) uplink transmissions.

5. The method of claim 1 , wherein prompting the plurality of second communication devices to transmit respective beamforming training packets comprises transmitting respective packets to second communication devices in the plurality of second communication devices to individually prompt second communication devices in the plurality of second communication devices to transmit respective beamforming training packets.

6. An apparatus, comprising:

a network interface device of a first communication device, the network interface device having one or more integrated circuit devices configured to:

prompt a plurality of second communication devices to transmit, to the first communication device, respective beamforming training packets as part of a procedure for developing respective transmit beamforming matrices for use by the plurality of second communication devices,

receive the respective beamforming training packets transmitted by the plurality of second communication devices as part of the procedure for developing the respective transmit beamforming matrices and in response to the prompt,

generate respective beamforming feedback packets based on reception of the respective beamforming training packets,

transmit the respective beamforming feedback packets as part of the procedure for developing the respective transmit beamforming matrices,

select a group of multiple second communication devices from among the plurality of second communication devices using channel information developed based on reception of the respective beamforming training packets, the group selected for simultaneous transmissions to the first communication device,

transmit a synchronization signal to the group to prompt second communication devices in the group to simultaneously transmit to the first communication device at a particular time, and

receive simultaneous transmissions from the group responsive to the synchronization signal, the simultaneous transmissions having been beamformed by second communication devices in the group using transmit beamforming matrices developed by the second communication devices in the group as part of the procedure for developing respective transmit beamforming matrices for use by the plurality of second communication devices.

7. The apparatus of claim 6 , wherein each beamforming training packet is a null data packet (NDP).

8. The apparatus of claim 6 , wherein:

the first communication device is an access point; and

the plurality of second communication devices are stations associated with the access point.

9. The apparatus of claim 6 , wherein the one or more integrated circuit devices are configured to select the group for multi-user (MU) multiple input, multiple output (MIMO) uplink transmissions.

10. The apparatus of claim 6 , wherein the one or more integrated circuit devices are configured to prompt the plurality of second communication devices to transmit respective beamforming training packets by transmitting respective packets to second communication devices in the plurality of second communication devices to individually prompt second communication devices in the plurality of second communication devices to transmit respective beamforming training packets.

11. An apparatus, comprising:

a network interface device of a first communication device, the network interface device having one or more integrated circuit devices configured to:

receive a prompt from a second communication device, the prompt for the first communication device to transmit a beamforming training packet to the second communication device as part of a beamforming training procedure for developing a transmit beamforming matrix for use by the first communication device when transmitting to the second communication device simultaneously with one or more third communication devices transmitting to the second communication device,

in response to the prompt, transmit the beamforming training packet to the second communication device as part of the beamforming training procedure,

receiving, from the second communication device, a beamforming feedback packet as part of the beamforming training procedure,

generate a transmit beamforming matrix for use by the first communication device when transmitting to the second communication device simultaneously with the one or more third communication devices transmitting to the second communication device,

receive a synchronization signal transmitted, by the second communication device, to a group of communication devices to prompt communication devices in the group to simultaneously transmit to the second communication device at a particular time, wherein the group comprises the first communication device and the one or more third communication devices, and

transmit a data packet to the second communication device simultaneous with transmissions by the one or more third communication devices to the second communication device, wherein

transmission of the data packet includes utilizing the transmit beamforming matrix, and

transmission of the data packet and the transmissions by the one or more third communication devices are responsive to the synchronization signal.

12. The apparatus of claim 11 , wherein the beamforming training packet is a null data packet (NDP).

13. The apparatus of claim 11 , wherein:

the second communication device is an access point; and

i) the first communication device and ii) the one or more third communication devices are stations associated with the access point.

14. The apparatus of claim 11 , wherein:

the group is selected for multi-user (MU) multiple input, multiple output (MIMO) uplink transmissions; and

the one or more integrated circuit devices are configured to transmit the data packet to the second communication device as part of a MU MIMO uplink transmission that includes the transmissions by the one or more third communication devices.

15. The apparatus of claim 11 , wherein the one or more integrated circuit devices are further configured to:

receive a polling signal transmitted by the second communication device; and

transmit the beamforming training packet in responsive to the polling signal.

16. An apparatus, comprising:

a network interface device of a first communication device, the network interface device having one or more integrated circuit devices configured to:

transmit a beamforming training packet as part of a beamforming training procedure for developing a transmit beamforming matrix for use by the first communication device,

receive a plurality of respective beamforming feedback packets from a plurality of second communication devices, the plurality of beamforming feedback packets being part of the beamforming training procedure for developing the transmit beamforming matrix for use by the first communication device,

use the plurality of beamforming feedback packets to select a group of multiple communication devices from among the plurality of second communication devices, the group selected for simultaneous transmissions to the first communication device,

transmit a synchronization signal to the group to prompt second communication devices in the group to simultaneously transmit to the first communication device at a particular time, and

receive simultaneous transmissions from the group responsive to the synchronization signal.

17. The apparatus of claim 16 , wherein the beamforming training packet is a null data packet (NDP).

18. The apparatus of claim 16 , wherein:

the first communication device is an access point; and

the plurality of second communication devices are stations associated with the access point.

19. The apparatus of claim 16 , wherein the group is selected for multi-user (MU) multiple input, multiple output (MIMO) uplink transmissions.

20. The apparatus of claim 16 , wherein the one or more integrated circuit devices are further configured to transmit, from the first communication device, one or more polling signals to prompt one or more second communication devices among the plurality of second communication devices to transmit the respective beamforming feedback packets.

21. An apparatus, comprising:

a network interface device of a first communication device, the network interface device having one or more integrated circuit devices configured to:

receive a beamforming training packet transmitted by a second communication device as part of a beamforming training procedure for developing a first transmit beamforming matrix for use by the second communication device,

generate a beamforming feedback packet based on reception of the beamforming training packet,

transmit the beamforming feedback packet as part of the beamforming training procedure for developing the first transmit beamforming matrix for use by the second communication device,

generate a second beamforming matrix for use by the first communication device when transmitting to the second communication device simultaneously with one or more third communication devices transmitting to the second communication device,

receive a synchronization signal transmitted, by the second communication device, to a group of communication devices to prompt communication devices in the group to simultaneously transmit to the second communication device at a particular time, wherein the group comprises the first communication device and the one or more third communication devices, and

transmit a data packet to the second communication device simultaneous with transmissions by the one or more third communication devices to the second communication device, wherein

transmission of the data packet is responsive to the synchronization signal, and

the network interface device utilizes the second beamforming matrix when transmitting the data packet.

22. The apparatus of claim 21 , wherein the beamforming training packet is a null data packet (NDP).

23. The apparatus of claim 21 , wherein:

the second communication device is an access point; and

i) the first communication device and ii) the one or more third communication devices are stations associated with the access point.

24. The apparatus of claim 21 , wherein:

the group is selected for multi-user (MU) multiple input, multiple output (MIMO) uplink transmissions; and

i) transmitting a data packet to the second communication device and ii) the transmissions by the one or more third communication devices are part of a MU MIMO uplink transmission.

25. The apparatus of claim 21 , wherein the one or more integrated circuit devices are further configured to:

receive a polling signal transmitted by the second communication device; and

transmit the beamforming feedback packet in response to the polling signal.