Systems and methods for optimizing sounding interval
Systems and methods are disclosed for optimizing the sounding interval in a MIMO communications system. Following a channel sounding protocol, net throughput may be estimated over time. The sounding interval may correspond to the period of time between the end of the sounding protocol and a time when the estimated net throughput is maximized. Estimating net throughput may involve estimating the number of bits that may be successfully transmitted divided by the time required to transmit. The number of bits that may be successfully transmitted may be estimated from a statistical channel profile including goodput.
1. A method for communication in a multiple input multiple output (MIMO) system comprising:
performing a channel sounding protocol during a first time period;
defining a plurality of bins beginning with a first bin and extending from an end of the first time period;
estimating net throughput during a second time period following the first time period by:
selecting a second bin, subsequent to the first bin;
summing bits that may be successfully transmitted during the first bin, the second bin, and intervening bins between the first bin and the second bin; and
dividing the summed bits by a duration of time extending from the first bin to the second bin plus the first time period;
determining a time corresponding to a maximum net throughput, wherein the time is within the second time period; and
determining a sounding interval based, at least in part, on a third time period extending between the end of the first time period and the time corresponding to the maximum net throughput.
2. The method of claim 1 , wherein estimating net throughput during the second time period comprises estimating a number of bits that may be successfully transmitted in each bin.
3. The method of claim 1 , wherein determining the time corresponding to the maximum net throughput comprises selecting the second bin such that net throughput at the second bin is the maximum net throughput.
4. The method of claim 2 , wherein estimating the number of bits that may be successfully transmitted in each bin comprises statistically determining goodput for each bin.
5. The method of claim 4 , wherein statistically determining goodput comprises:
transmitting a first plurality of packets of information over at least one preceding sounding interval initiated by performing a sounding protocol, wherein each packet has a transmission time, is addressed to at least one station and is transmitted in at least one MIMO mode;
binning each packet of information in one bin of the plurality of bins based, at least in part, on the transmission time of each packet relative to the sounding protocol of the at least one preceding sounding interval; and
determining a goodput value corresponding to the bin, the station and the MIMO mode for each packet that is acknowledged.
6. The method of claim 1 , wherein determining the sounding interval comprises multiplying a number of bins between the first bin and the second bin, inclusive, by a duration of each bin.
7. A wireless communications device to operate in a multiple input multiple output (MIMO) system, comprising:
a number of transmitter units to transmit a channel sounding protocol during a first time period; and
a statistics estimator to:
define a plurality of bins beginning with a first bin and extending from an end of the first time period;
estimate net throughput during a second time period following the first time period by:
selecting a second bin subsequent to the first bin;
summing bits that may be successfully transmitted during the first bin, the second bin and intervening bins between the first bin and the second bin; and
dividing the summed bits by a duration of time extending from the first bin to the second bin plus the first time period;
determine a time corresponding to a maximum net throughput, wherein the time is within the second time period; and
determine a sounding interval based, at least in part, on a third time period extending between the end of the first time period and the time corresponding to the maximum net throughput.
8. The wireless communications device of claim 7 , wherein the statistics estimator is to estimate net throughput during the second time period by estimating a number of bits that may be successfully transmitted in each bin.
9. The wireless communications device of claim 7 , wherein the statistics estimator is to determine the time corresponding to the maximum net throughput by selecting the second bin such that net throughput at the second bin is the maximum net throughput.
10. The wireless communications device of claim 8 , wherein the statistics estimator is to estimate the number of bits that may be successfully transmitted in each bin based, at least in part, on a statistically determined goodput for each bin.
11. The wireless communications device of claim 10 , wherein the transmitter units are to transmit a first plurality of packets of information over at least one preceding sounding interval initiated by performing a sounding protocol, wherein each packet has a transmission time, is addressed to at least one station and is transmitted in at least one MIMO mode; and
wherein the statistics estimator is to determine goodput by:
binning each packet of information in one bin of the plurality of bins based, at least in part, on the transmission time of each packet relative to the sounding protocol of the at least one preceding sounding interval; and
determining a goodput value corresponding to the bin, the station and the MIMO mode for each packet that is acknowledged.
12. The wireless communications device of claim 7 , wherein the statistics estimator is to determine the sounding interval by multiplying a number of bins between the first bin and the second bin, inclusive, by a duration of each bin.
13. A non-transitory processor-readable storage medium for operating a multiple input multiple output (MIMO) wireless communications device, the processor-readable storage medium storing instructions that, when executed by a processor, cause the wireless communications device to:
perform a channel sounding protocol during a first time period;
define a plurality of bins beginning with a first bin and extending from an end of the first time period;
estimate net throughput during a second time period following the first time period by:
selecting a second bin subsequent to the first bin;
summing bits that may be successfully transmitted during the first bin, the second bin and intervening bins between the first bin and the second bin; and
dividing the summed bits by a duration of time extending from the first bin to the second bin plus the first time period;
determine a time corresponding to a maximum net throughput, wherein the time is within the second time period; and
determine a sounding interval based, at least in part, on a third time period extending between the end of the first time period and the time corresponding to the maximum net throughput.
14. The storage medium of claim 13 , wherein the instructions to cause the wireless communications device to estimate net throughput during the second time period comprises instructions to cause the wireless communications device to estimate a number of bits that may be successfully transmitted in each bin.
15. The storage medium of claim 13 , wherein the instructions to cause the wireless communications device to determine the time corresponding to the maximum net throughput comprises instructions to cause the wireless communications device to select the second bin such that net throughput at the second bin is the maximum net throughput.
16. The storage medium of claim 14 , wherein the instructions to cause the wireless communications device to estimate the number of bits that may be successfully transmitted in each bin comprises instructions to cause the wireless communications device to statistically determine a goodput for each bin.
17. The storage medium of claim 16 , wherein the instructions to cause the wireless communications device to statistically determine goodput comprises:
instructions to cause the wireless communications device to transmit a first plurality of packets of information over at least one preceding sounding interval initiated by performing a sounding protocol, wherein each packet has a transmission time, is addressed to at least one station and is transmitted in at least one MIMO mode;
instructions to cause the wireless communications device to bin each packet of information in one bin of the plurality of bins based, at least in part, on the transmission time of each packet relative to the sounding protocol of the at least one preceding sounding interval; and
instructions to cause the wireless communications device to determine a goodput value corresponding to the bin, the station and the MIMO mode for each packet that is acknowledged.
18. The storage medium of claim 13 , wherein the instructions to cause the wireless communications device to determine the sounding interval comprises instructions to cause the wireless communications device to multiply a number of bins between the first bin and the second bin, inclusive, by a duration of each bin.