Method and apparatus for enhanced data rate adaptation and lower power control in a WLAN semiconductor chip
View Patent ↗A method of optimising the operation of a WLAN device which is used in the transmission and reception of a service over a medium includes determining a the value of a collision avoidance metric of the chip set at a specific time; predicting the available bandwidth of the WLAN from the value of the metric; determining the current data rate of the WLAN based on predicted available bandwidth and the type of service; and selecting a power amplifier bias voltage that is the minimum permitted for the determined current data rate to reduce the power consumption of the WLAN device.
1. A method of configuring the operation of a wireless local area network (WLAN) device which is used in the transmission and reception of a service over a medium, the WLAN device comprising a WLAN chip set and power amplifier, the method comprising the steps of:
determining, based on a measurement of network performance, a value of a WLAN traffic indicator metric used in the chip set at a specific time to estimate the WLAN traffic, the WLAN traffic indicator indicating an amount of WLAN traffic;
predicting an estimation of the available bandwidth of the WLAN from the value of the metric;
calculating a data rate of the WLAN based on estimated available bandwidth, a target packet error rate, and a required throughput value, wherein calculating the data rate of the WLAN based on the estimated available bandwidth, the required throughput value, and the target packet error rate includes: multiplying the required throughput value by a multiplier to take into account the target packet error rate, and then dividing the result by the estimated available bandwidth; and
selecting a power amplifier bias voltage at the WLAN device that is the minimum determined from a look up table of power amplifier bias voltage and data rate for the data rate.
2. The method of claim 1 , further comprising, calculating a level for the transmission power of the WLAN chip set from the data rate.
3. The method of claim 2 , wherein the calculating step comprises:
selecting a level for the transmission power for the WLAN based a comparison of the data rate with a last known data rate of the device and based on a comparison of a packet error rate (PER) with the target packet error rate.
4. The method of claim 3 , further comprising applying a first power reduction step to the transmission power as a result of the comparison of the data rate with the last known data-rate.
5. The method of claim 4 , further comprising applying the power reduction step based on the power ratio of the sensitivities of a current and a latest standard defined sensitivity of the WLAN.
6. The method of claim 3 , further comprising applying a second power reduction step to the transmission power as a result of the comparison between the PER with the target PER.
7. The method of claim 4 , wherein the steps of applying a power reduction are continued until the PER matches the target PER.
8. The method of claim 1 , wherein the step of determining the value of a WLAN traffic indicator metric of the chip set at a specific time comprises determining a metric from the set comprising Network Allocation Vector, Received Signal Strength Indicator level and Clear Channel Assessment.
9. A wireless local area network (WLAN) device comprising:
a WLAN chip set and a power amplifier for transmitting a service over a medium wherein the WLAN chip set includes a medium access controller;
a modem;
a receiver; and
a transmitter, wherein the medium access controller includes a link adaptation model to calculate a data rate from the value of a WLAN traffic indicator metric based on an estimated available bandwidth, a target packet error rate, and a required throughput value, the WLAN traffic indicator indicating an amount of WLAN traffic and wherein the modem uses the current data rate to determine a bias voltage for the power amplifier, which voltage is selected to be the minimum determined from a look up table of power amplifier bias voltage and data rate for the calculated data rate to reduce the power consumption of the power amplifier, wherein calculating the data rate of the WLAN based on the estimated available bandwidth, the required throughput value, and the target packet error rate includes: multiplying the required throughput value by a multiplier to take into account the target packet error a and then dividing h result by the estimated available bandwidth.
10. The WLAN device of claim 9 wherein the modem further generates a transmitter power control signal to minimise the power of the transmitter.
11. The WLAN device of claim 10 , wherein the power control signal depends on a comparison of data rate with a last known data rate of the device.
12. The WLAN device of claim 10 , wherein the power control signal depends on a comparison of the packet error rate with the target error rate.
13. The WLAN device of claim 9 , wherein the value of the WLAN traffic Indicator metric of the chip set is used to predict the available bandwidth in order to determine the data rate.
14. The WLAN device of claim 9 , wherein the WLAN traffic Indicator metric of the chip set comprises Network Allocation Vector, Received Signal Strength Indicator level and Clear Channel Assessment.
15. The WLAN device according to claim 9 , wherein the service is Voice over IP.
16. The WLAN device of claim 9 , wherein the service is Voice and Video over IP.
17. A method of optimising the operation of a WLAN device which is used in the transmission and reception of a service over a medium, the WLAN device comprising a WLAN chip set and power amplifier, the method comprising the steps of:
determining a value of a WLAN traffic indicator metric used in the chip set at a specific time;
estimating an available bandwidth of the WLAN from the value of the metric;
determining the a data rate of the WLAN based on estimated available bandwidth and the type of service;
selecting a power amplifier bias voltage that is the minimum determined from a look up table of power amplifier bias voltage and data rate for the determined data rate to reduce power consumption of the WLAN device; and
generating a power control signal for minimizing the power of a transmitter of the WLAN device depending on a difference between a first and a second sensitivity predefined for the WLAN device for the determined data rate and a last known data rate and, when the determined data rate equals the last known data rate, depending on a size of a power step of the WLAN chip set and a difference of a packet error rate and a target error rate.
18. The method of claim 17 , further comprising:
calculating a level for the transmission power of the WLAN chip set from the data rate.
19. The method of claim 18 , wherein the calculating step comprises:
selecting a level for the transmission power for the WLAN based a comparison of the data rate with a last known data rate of the device and based on a comparison of a packet error rate with the target packet error rate.
20. The method of claim 19 , further comprising:
applying a first power reduction step to the transmission power as a result of the comparison of the data rate with the last known data-rate.