MU-MIMO grouping system
Embodiments herein describe a network device (e.g., an access point) that dynamically arranges multi-user (MU) multiple input multiple output (MIMO) compatible client devices into MU-MIMO groups. That is, the network device uses network metrics and historical data to change the assignment of client devices in the MU-MIMO groups which may improve MU-MIMO efficiency by reducing the amount of power that leaks between the clients devices in the group. In one embodiment, the AP identifies a MU-MIMO group based on a performance evaluation such as evaluating network metric or determining if the group is underutilized. The AP can replace the identified MU-MIMO group with a substitute MU-MIMO group where the substitute MU-MIMO group is selected based on historical data corresponding to the client devices assigned to the substitute MU-MIMO group.
1. A network device, comprising:
at least one radio;
an antenna coupled to the at least one radio; and
control logic configured to:
form a plurality of multi user multiple input multiple output (MU-MIMO) groups, each of the plurality of MU-MIMO groups comprising a first plurality of client devices;
transmit MU-MIMO data to the client devices using the plurality of MU-MIMO groups and the radio;
schedule a plurality of different sets of client devices for data transmission;
upon determining none of the plurality of MU-MIMO groups contains the sets of client devices, transmit data to the sets of client devices using single-user transmission;
track the number of times data is scheduled for transmission to the sets of client devices using single-user transmission;
identify one of the plurality of MU-MIMO groups based on a performance evaluation; and
replace the identified MU-MIMO group with a substitute MU-MIMO group selected from one of the sets of client devices which was scheduled most often for data transmission.
2. The network device of claim 1 , wherein the performance evaluation comprises evaluating at least one of coherency times and inter-client channel correlation values associated with the identified MU-MIMO group.
3. The network device of claim 2 , wherein the control logic is configured to, before replacing the identified MU-MIMO group with the substitute MU-MIMO group:
assign respective scores to the plurality of MU-MIMO groups and the substitute MU-MIMO group based on the coherency times and inter-client channel correlation values.
4. The network device of claim 2 , wherein the control logic is configured to, before replacing the identified MU-MIMO group with the substitute MU-MIMO group:
rank a plurality of inactive MU-MIMO groups using respective scores based on the coherency times and inter-client channel correlation values, wherein the plurality of inactive MU-MIMO groups are not available for MU-MIMO, wherein the plurality of inactive MU-MIMO groups comprises the substitute MU-MIMO group; and
select the substitute MU-MIMO group to replace the identified MU-MIMO group in response to the substitute MU-MIMO group having a higher score than the identified MU-MIMO group.
5. The network device of claim 1 , wherein the control logic is configured to:
monitor data rates corresponding to the first plurality of client devices assigned to the plurality of MU-MIMO groups;
update respective scores corresponding to the plurality of MU-MIMO groups based on the data rates; and
select the identified MU-MIMO group from among the plurality of MU-MIMO groups using the respective scores.
6. The network device of claim 1 , wherein forming the plurality of MU-MIMO groups comprises:
randomly assigning each of the first plurality of client devices into a predefined number of the plurality of MU-MIMO groups, wherein the predefined number is greater than one.
7. The network device of claim 1 , wherein the control logic is configured to:
transmit a MU-MIMO management frame to a client device only when the control logic changes a mapping from group identifier to user position for the client device.
8. The network device of claim 1 , wherein the control logic is configured to:
transmit at least one MU-MIMO management frame when the control logic at least one of changes a number of the first plurality of client devices in one of the plurality of MU-MIMO groups and changes one of the plurality of MU-MIMO groups between inactive and active states.
9. The network device of claim 1 , wherein replacing the identified MU-MIMO group with the substitute MU-MIMO group comprises:
deactivating the identified MU-MIMO group such the identified MU-MIMO group is not available for transmitting MU-MIMO traffic.
10. A non-transitory computer-readable storage medium for operating a network device, the computer-readable storage medium comprising:
computer-readable program code configured to perform an operation when executed on a computing processor, the operation comprising:
forming a plurality of MU-MIMO groups, each of the plurality of MU-MIMO groups comprising a first plurality of client devices;
transmitting MU-MIMO data to the client devices using the plurality of MU-MIMO groups;
scheduling a plurality of different sets of client devices for data transmission;
upon determining none of the plurality of MU-MIMO groups contains the sets of client devices, transmitting data to the sets of client devices using single-user transmission;
tracking the number of times data is scheduled for transmission to the sets of client devices using single-user transmission;
identifying one of the plurality of MU-MIMO groups based on a performance evaluation; and
replacing the identified MU-MIMO group with a substitute MU-MIMO group selected from one of the sets of client devices which was scheduled most often for data transmission.
11. The computer-readable storage medium of claim 10 , wherein the performance evaluation comprises evaluating at least one of coherency times of channels and inter-client channel correlation values associated with the identified MU-MIMO group.
12. The computer-readable storage medium of claim 11 , wherein the operation comprises, before replacing the identified MU-MIMO group with the substitute MU-MIMO group:
assigning respective scores to the plurality of MU-MIMO groups and the substitute MU-MIMO group based on the coherency times and inter-client channel correlation values.
13. The computer-readable storage medium of claim 11 , wherein the operation comprises, before replacing the identified MU-MIMO group with the substitute MU-MIMO group:
ranking a plurality of inactive MU-MIMO groups using respective scores based on the coherency times and inter-client channel correlation values, wherein the plurality of inactive MU-MIMO groups are not available for MU-MIMO, wherein the plurality of inactive MU-MIMO groups comprises the substitute MU-MIMO group; and
selecting the substitute MU-MIMO group to replace the identified MU-MIMO group in response to the substitute MU-MIMO group having a higher score than the identified MU-MIMO group.
14. The computer-readable storage medium of claim 10 , wherein the operation comprises:
monitoring data rates corresponding to the first plurality of client devices assigned to the plurality of MU-MIMO groups;
updating respective scores corresponding to the plurality of MU-MIMO groups based on the data rates; and
selecting the identified MU-MIMO group from among the plurality of MU-MIMO groups using the respective scores.
15. The computer-readable storage medium of claim 10 , wherein forming the plurality of MU-MIMO groups comprises:
randomly assigning each of the first plurality of client devices into a predefined number of the plurality of MU-MIMO groups, wherein the predefined number is greater than one.
16. A method of operating a network device, comprising:
forming a plurality of MU-MIMO groups, each of the plurality of MU-MIMO groups comprising a first plurality of client devices;
transmitting MU-MIMO data to the client devices using the plurality of MU-MIMO groups;
scheduling a plurality of different sets of client devices for data transmission;
upon determining none of the plurality of MU-MIMO groups contains the sets of client devices, transmitting data to the sets of client devices using single-user transmission;
tracking the number of times data is scheduled for transmission to the sets of client devices using single-user transmission;
identifying one of the plurality of MU-MIMO groups based on a performance evaluation; and
replacing the identified MU-MIMO group with a substitute MU-MIMO group selected from one of the sets of client devices which was scheduled most often for data transmission.