Beamformer solicited sounding

1. A method comprising:

receiving, by a second access point, a sounding trigger broadcast by a first access point, while opportunistically monitoring for triggers without coordination with the first access point;

receiving, by the second access point, a first dedicated training signal from a first station in response to the sounding trigger broadcast by the first access point without the second access point sending a separate sounding trigger to the first station; and

generating, by the second access point, channel characteristics of a channel based on the first dedicated training signal, the channel including a forward channel between the second access point and the first station.

2. The method of claim 1 , further comprising transmitting packets over the channel from the second access point to the first station, the packets precoded using precoding derived from the channel characteristics.

3. The method of claim 1 , further comprising:

transmitting a second dedicated training signal from the second access point to the first station;

receiving, by the second access point, feedback from the first station in response to the second dedicated training signal; and

calibrating beamforming between the second access point and the first station based on analysis of a first channel estimation based on the channel characteristics and a second channel estimation based on the received feedback.

4. The method of claim 1 , further comprising:

receiving, by the second access point, a second dedicated training signal from a second station in response to the sounding trigger broadcast by the first access point; and

generating, by the second access point, second channel characteristics of a second channel based on the second dedicated training signal, the second channel including a second forward channel between the second access point and the second station.

5. The method of claim 4 , wherein the first dedicated training signal and the second dedicated training signal are multiplexed and at least partially overlapping in time based on information in the sounding trigger.

6. The method of claim 4 , wherein the first dedicated training signal and the second dedicated training signal are received sequentially in time based on information in the sounding trigger.

7. The method of claim 1 , wherein the sounding trigger includes training options for the first station to format the first dedicated training signal including at least one of: repeated symbols to be included in the first dedicated training signal, partial bandwidth to be used when transmitting the first dedicated training signal, a number of bits to be included in the first dedicated training signal, and a schedule according to which the first station is to transmit additional dedicated training signals.

8. A system comprising:

one or more processors; and

one or more non-transitory computer-readable media containing instructions that, when executed by the one or more processors, are configured to cause the system to perform operations, the operations comprising:

receiving a sounding trigger broadcast by a first beamformer, the system acting as a second beamformer;

reserving, by the second beamformer, network resources identified by the first beamformer in the sounding trigger via which a first beamformee is instructed to transmit a first dedicated training signal;

receiving, by the second beamformer, the first dedicated training signal from the first beamformee via the reserved network resources, the first dedicated training signal transmitted by the first beamformee in response to the sounding trigger broadcast by the first beamformer; and

generating, by the second beamformer, channel characteristics of a channel based on the first dedicated training signal, the channel including a forward channel to the first beamformee.

9. The system of claim 8 , wherein the operations further comprise transmitting packets to the first beamformee, the packets precoded using precoding derived from the channel characteristics.

10. The system of claim 8 , wherein the operations further comprise:

transmitting a second dedicated training signal to the first beamformee;

receiving feedback from the first beamformee in response to the second dedicated training signal; and

calibrating beamforming for the forward channel to the first beamformee based on analysis of a first channel estimation based on the channel characteristics and a second channel estimation based on the received feedback.

11. The system of claim 8 , wherein the operations further comprise:

receiving a second dedicated training signal from a second beamformee in response to the sounding trigger broadcast by the first beamformer; and

generating second channel characteristics regarding a second channel based on the second dedicated training signal, the second channel including a second forward channel to the second beamformee.

12. The system of claim 11 , wherein the first dedicated training signal and the second dedicated training signal are multiplexed and at least partially overlapping in time based on information in the sounding trigger.

13. The system of claim 11 , wherein the first dedicated training signal and the second dedicated training signal are received sequentially in time based on information in the sounding trigger.

14. The system of claim 8 , wherein the operations further comprise receiving a message from the first beamformer establishing a master and slave relationship between the first beamformer and the system such that the first beamformer transmits the sounding trigger instead of the system.

15. The system of claim 8 , wherein the sounding trigger includes training options for the first beamformee to format the first dedicated training signal including at least one of: repeated symbols to be included in the first dedicated training signal, partial bandwidth to be used when transmitting the first dedicated training signal, a number of bits to be included in the first dedicated training signal, and a schedule according to which the first beamformee is to transmit additional dedicated training signals.

16. An access point, comprising:

one or more processors; and

one or more non-transitory computer-readable media containing instructions that, when executed by the one or more processors, are configured to cause the access point to perform operations, the operations comprising:

opportunistically monitoring for triggers from a separate access point without coordination with the separate access point;

while opportunistically monitoring, observing a sounding trigger broadcast from the separate access point;

receiving a first dedicated training signal from a first station generated in response to the sounding trigger broadcast by the separate access point; and

generating first channel characteristics regarding a first channel based on the first dedicated training signal, the first channel including communication between the access point and the first station.

17. The access point of claim 16 , wherein the operations further comprise:

receiving a second dedicated training signal from a second station in response to the sounding trigger; and

generating second channel characteristics regarding a second channel based on the second dedicated training signal, the second channel including communication between the access point and the second station.