Method and system for managing power consumption of a network interface module in a wireless computing device

• US 20030210658A1
• Filed: 05/08/2002
• Published: 11/13/2003
• Est. Priority Date: 05/08/2002
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Moore, Timothy M., Ayyagari, Arun, Bahl, Pradeep, Ganugapati, Krishna, Hernandez, Edwin
• Granted Patent: US 7,564,810 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• CPC Class Codes: H04W 52/0232 according to average transmission signal activity
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A power management scheme for use in a wireless device reduces the power consumption of the network interface module of the wireless device by selectively putting the network interface module into a low-power state for an idle time. The length of the idle time is calculated such that the amount of delayed traffic data accumulated is expected to be less than or equal to a pre-selected threshold when the network interface module is put in the low-power state for the calculated idle time. The amount of delayed traffic data as a function of the idle time is modeled using average inter-arrival and service rates that are derived from traffic statistics data.

Claims

1. A method for managing power consumption of a wireless computing device having a network interface module for transmitting and receiving wireless network communication data, the method comprising:

analyzing traffic statistics data to derive parameters of a model for predicting an amount of delayed traffic data that will accumulate as a function of time when the network interface module is put in a low-power state in which the network interface module stops transmitting network communication data; and

calculating a target idle time for the network interface module based on the model with the derived parameters, wherein putting the network interface module in the low-power state for the target idle time is predicted by the model to result in an amount of delayed traffic data that is less than or equal to a pre-selected threshold.

2. A method as in claim 1, further including:

determining that the wireless device is connected to an access point of an infrastructure network; and

switching the network interface module into the low-power state for the target idle time.

3. A method as in claim 1, further including:

determining that the wireless device is connected to an ad hoc wireless network;

broadcasting the target idle time to other wireless devices in the ad hoc wireless network;

receiving target idle times calculated and broadcast by the other wireless devices in the ad hoc wireless network;

selecting a smallest one of the broadcast target idle times as a common idle time for the wireless devices in the ad hoc wireless network; and

switching the network interface module into the low-power state for the common idle time.

4. A method as in claim 1, wherein the parameters of the model for predicting the amount of delayed traffic data include an average inter-arrival rate and an average service rate, and wherein the step of analyzing the traffic statistics data includes:

retrieving the traffic statistics data including a set of historical inter-arrival rates, a set of historical service rates, and a set of numbers of traffic data in the system queue;

modeling the historical inter-arrival rates using a first distribution function, and the historical service rates using a second distribution function; and

deriving the average inter-arrival rate and the average service rate based on the first and second distribution functions, respectively.

5. A method as in claim 4, further including updating the traffic statistics data by collecting a current inter-arrival rate and a current service rate.

6. The method of claim 4, wherein the first distribution function is an exponential distribution function

7. A method as in claim 4, wherein the second distribution function is a Pareto distribution function.

8. A computer-readable medium having computer-executable instructions for performing steps for managing power consumption of a wireless computing device having a network interface module) for transmitting and receiving wireless network communication data, comprising:

analyzing traffic statistics data to derive parameters of a model for predicting an amount of delayed traffic data that will accumulate as a function of time when the network interface module is put in a low-power state in which the network interface module stops transmit network communication data; and

calculating a target idle time for the network interface module based on the model with the derived parameters, wherein putting the network interface module in the low-power state for the target idle time is predicted by the model to result in an amount of delayed traffic data that is less than or equal to a pre-selected threshold.

9. A computer-readable medium as in claim 8, having further computer-executable instructions for performing the steps of:

determining that the wireless device is connected to an access point of an infrastructure network; and

switching the network interface module into the low-power state for the target idle time.

10. A computer-readable medium as in claim 8, having further computer-executable instructions for performing the steps of:

determining that the wireless device is connected to an ad hoc wireless network;

broadcasting the target idle time to other wireless devices in the ad hoc wireless network;

receiving target idle times calculated and broadcast by the other wireless devices in the ad hoc wireless network;

selecting a smallest one of the broadcast target idle times as a common idle time for the wireless devices in the ad hoc wireless network; and

switching the network interface module into the low-power state for the common idle time.

11. A computer-readable medium as in claim 8, wherein the parameters of the model for predicting the amount of delayed traffic data include an average inter-arrival rate and an average service rate, and wherein the step of analyzing the traffic statistics data includes:

retrieving the traffic statistics data including a set of historical inter-arrival rates, a set of historical service rates, and a set of numbers of traffic data in the system queue;

modeling the historical inter-arrival rates using a first distribution function, and the historical service rates using a second distribution function; and

deriving the average inter-arrival rate and the average service rate based on the first and second distribution functions, respectively.

12. A computer-readable medium as in claim 11, having further computer-executable instructions for performing the step of updating the traffic statistics data by collecting a current inter-arrival rate and a current service rate.

13. A computer-readable medium as in claim 11, wherein the first distribution function is an exponential distribution function

14. A computer-readable medium as in claim 11, wherein the second distribution function is a Pareto distribution function.

15. A power management system for use in a wireless computing device having a network interface module for transmitting and receiving wireless network communications, comprising:

a traffic statistics database for storing traffic statistics data including a set of historical inter-arrival rates and a set of historical service rates; and

a power manager for selectively setting the network interface module into a low-power state, the power manager having a stochastic decider for analyzing the traffic statistics data to derive an average inter-arrival rate and an average service rate, and calculating a target idle time for the network interface module based on the average inter-arrival and service rates, the target idle time being predicted to result in an amount of delayed network traffic data that is less than or equal to a pre-selected threshold when the network interface module in put in the low-power state for the target idle time.

16. A power management system as in claim 15, wherein the power manager is programmed to switching the network interface module into the low-power state for the target idle time when the wireless device is connected to an access point of an infrastructure network.

17. A power management system as in claim 15, wherein the power manager is programmed to perform the steps of:

determining that the wireless device is connected to an ad hoc wireless network;

broadcasting the target idle time to other wireless devices in the ad hoc wireless network;

receiving target idle times calculated and broadcast by the other wireless devices in the ad hoc wireless network;

selecting a smallest one of the broadcast target idle times as a common idle time for the wireless devices in the ad hoc wireless network; and

switching the network interface module into the low-power state for the common idle time.

18. A power management system as in claim 15, wherein the stochastic decider is programmed to performed the steps of:

modeling the historical inter-arrival rates using a first distribution function, and the historical service rates using a second distribution function; and

deriving the average inter-arrival rate and the average service rate based on the first and second distribution functions, respectively.

19. A power management system as in claim 18, wherein the first distribution function is an exponential distribution function

20. A power management system as in claim 18, wherein the second distribution function is a Pareto distribution function.

21. A power management system as in claim 18, wherein the power manager is further programmed to update the traffic statistics data by collecting a current inter-arrival rate and a current service rate.

22. A mobile computing device comprising:

a power source for powering the mobile device;

a network interface module for transmitting and receiving wireless network communications;

a traffic statistics database for storing traffic statistics data including a set of historical inter-arrival rates and a set of historical service rates; and

a power manager for selectively setting the network interface module into a low-power state for reducing consumption of power of the power source, the power manager having a stochastic decider for analyzing the traffic statistics data to derive an average inter-arrival rate and an average service rate, and calculating a target idle time for the network interface module based on the average inter-arrival and service rates, the target idle time being predicted to result in an amount of delayed network traffic data that is less than or equal to a pre-selected threshold when the network interface module in put in the low-power state for the target idle time.

23. A mobile computing device as in claim 22, wherein the power source includes a battery pack.

24. A mobile computing device as in claim 22, wherein the power source is a fuel cell.

25. A mobile computing device as in claim 22, wherein the power manager is programmed to switching the network interface module into the low-power state for the target idle time when the wireless device is connected to an access point of an infrastructure network.

26. A mobile computing device as in claim 22, wherein the power manager is programmed to perform the steps of:

determining that the wireless device is connected to an ad hoc wireless network;

broadcasting the target idle time to other wireless devices in the ad hoc wireless network;

receiving target idle times calculated and broadcast by the other wireless devices in the ad hoc wireless network;

selecting a smallest one of the broadcast target idle times as a common idle time for the wireless devices in the ad hoc wireless network; and

switching the network interface module into the low-power state for the common idle time.