High spatial reuse for mmWave Wi-Fi

1. A method, comprising,

identifying, by a network device, a plurality of millimeter-wave (mmWave) propagation paths between the network device and a set of neighboring devices wherein the set includes a target neighboring device, based on power delay profiles (PDPs) of beam training frames received by the network device from each of the neighboring devices utilizing a plurality of mmWave beams;

wherein identifying the plurality of mmWave propagation paths between the network device and the set of neighboring devices comprises:

generating, by the network device, an aggregate path profile of the PDPs of the received beam training frames utilizing the mmWave beams, wherein the aggregate path profile maps an aggregate signal strength of the received beam training frames of the PDPs as a function of time delay;

identifying, by the network device, a number of impulses of the aggregate path profile at which the aggregate signal strength exceeds a predetermined threshold; and

determining, by the network device, that a total number of the mmWave propagation paths is equal to the number of impulses of the aggregate path profile;

determining, by the network device for each of neighboring devices in the set, an estimated angle of arrival (AoA) of each identified mmWave propagation path between the network device and the neighboring device, based on the PDPs of the received beam training frames from the neighboring device;

selecting, by the network device, one of the mmWave beams that maximizes a signal to interference and noise ratio (SINR) along the estimated AoA of each identified mmWave propagation path between the network device and the target neighboring device; and

communicating, by the network device, with the target neighboring device utilizing the selected mmWave beam.

2. The method of claim 1 , wherein the selected mmWave beam minimizes interference from an other neighboring network devices in the set than the target neighboring device along the estimated AoA of each identified mmWave propagation path between the network device and the other neighboring devices in the set than the target neighboring device.

3. The method of claim 1 , wherein generating the aggregate path profile comprises:

generating, by the network device, each of the PDPs, wherein each of the PDPs maps a signal strength of the received beam training frames by the network device utilizing one of the mmWave beams as a function of time delay;

identifying, by the network device for each of the PDPs, a number of impulses of the PDP at which the signal strength exceeds another predetermined threshold and a time delay associated with each impulse; and

generating, by the network device, the aggregate path profile by aligning the PDPs based on the time delays of the impulses of the PDPs and superimposing the aligned PDPs.

4. The method of claim 1 , wherein determining the estimated AoA of each identified mmWave propagation path between the network device and the neighboring device comprises:

generating, by the network device, a probability density function that indicates a probability of each of the identified mmWave propagation paths to be along each of a plurality of angles, based on the PDPs of the received beam training frames from the neighboring device; and

determining, by the network device for each of the identified mmWave propagation paths, that the estimated AoA of the identified mmWave propagation path corresponds to at least one of the angles that has a highest probability among the angles to be along the identified mmWave propagation path as indicated by the probability density function.

5. The method of claim 4 , wherein generating the probability density function comprises:

for each of the identified mmWave propagation paths:

for each of the mmWave beams of the identified mmWave propagation path:

determining, by the network device for each of the angles, a beam directivity gain of a predetermined radiation pattern of the received beam training frames along the angle;

determining, by the network device, a path strength gain of the identified mmWave propagation path utilizing the mmWave beam, based on the PDPs of the received beam training frames from the neighboring device; and

computing, by the network device for each of the angles, a product of the beam directivity gain along the angle and the path strength gain of the identified mmWave propagation path utilizing the mmWave beam.

6. The method of claim 1 , wherein selecting the one of the mmWave beams comprises:

determining, by the network device for each of the mmWave beams, a ratio between:

(1) a sum of beam directivity gains along the estimated AoA of each identified mmWave propagation path between the network device and the target neighboring device; and

(2) a sum of beam directivity gains along the estimated AoA of each identified mmWave propagation path between the network device and every other neighboring device in the set; and

determining, by the network device, that the selected one of the mmWave beams has a highest value of the ratio among the ratios of the mmWave beams.

7. The method of claim 1 , wherein communicating with the target neighboring device utilizing the selected mmWave beam comprises:

receiving, by the network device from the target neighboring device, a mmWave signal along the estimated AoA corresponding to the selected mmWave beam.

8. The method of claim 1 , wherein communicating with the target neighboring device utilizing the selected mmWave beam comprises:

transmitting, by the network device to the target neighboring device, a mmWave signal along the estimated AoA corresponding to the selected mmWave beam.

9. The method of claim 1 , wherein the network device communicates with the target neighboring device utilizing a mmWave operating channel according to one of the IEEE 802.11ad and 802.11ay standards.

10. An article comprising at least one non-transitory machine-readable storage medium comprising instructions executable by at least one processing resource of a network device to:

identify a plurality of millimeter-wave (mmWave) propagation paths between the network device and a set of neighboring devices wherein the set includes a target neighboring device, based on power delay profiles (PDPs) of beam training frames received by the network device from each of the neighboring devices utilizing a plurality of mmWave beams;

determine, for each of neighboring devices in the set, an estimated angle of arrival (AoA) of each identified mmWave propagation path between the network device and the neighboring device, based on the PDPs of the received beam training frames from the neighboring device;

wherein the instructions to determine the estimated AoA of each identified mmWave propagation path between the network device and the neighboring device comprise instructions to:

generate a probability density function that indicates a probability of each of the identified mmWave propagation paths to be along each of a plurality of angles, based on the PDPs of the received beam training frames from the neighboring device; and

determine, for each of the identified mmWave propagation paths, that the estimated AoA of the identified mmWave propagation path corresponds to at least one of the angles that has a highest probability among the angles to be along the identified mmWave propagation path as indicated by the probability density function:

select one of the mmWave beams that maximizes a signal to interference and noise ratio (SINR) along the estimated AoA of each identified mmWave propagation path between the network device and the target neighboring device; and

communicate with the target neighboring device utilizing the selected mmWave beam.

11. The article of claim 10 , wherein the instructions to identify the plurality of mmWave propagation paths between the network device and the set of neighboring devices comprise instructions to:

generate each of the PDPs, wherein each of the PDPs maps a signal strength of the received beam training frames by the network device utilizing one of the mmWave beams as a function of time delay;

identify, for each of the PDPs, a number of impulses of the PDP at which the signal strength exceeds a first predetermined threshold and a time delay associated with each impulse; and

generate an aggregate path profile by aligning the PDPs based on the time delays of the impulses of the PDPs and superimposing the aligned PDPs, wherein the aggregate path profile maps an aggregate signal strength of the received beam training frames of the PDPs as a function of time delay;

identify a number of impulses of the aggregate path profile at which the aggregate signal strength exceeds a second predetermined threshold; and

determine that a total number of the mmWave propagation paths is equal to the number of impulses of the aggregate path profile.

12. The article of claim 10 , wherein the instructions to select the one of the mmWave directional beams comprise instructions to:

determine, for each of the mmWave beams, a ratio between:

(1) a sum of beam directivity gains along the estimated AoA of each identified mmWave propagation path between the network device and the target neighboring device; and

(2) a sum of beam directivity gains along the estimated AoA of each identified mmWave propagation path between the network device and every other neighboring device in the set than the target neighboring device; and

determine that the selected one of the mmWave beams has a highest value of the ratio among the ratios of the mmWave beams.

13. The article of claim 10 , wherein the instructions to communicate with the target neighboring device utilizing the selected mmWave beam comprise instructions to:

receive, from the target neighboring device, a first mmWave signal along the estimated AoA corresponding to the selected mmWave beam; and

transmit, to the target neighboring device, a second mmWave signal along the estimated AoA corresponding to the selected mmWave beam.