System and method for conserving power for a wireless device while maintaining a connection to a network

1. A method for selectively reducing power consumption of a communication device communicating with a 802.11-class wireless network, comprising:

de-activating at least one communication subsystem of said device during intervals when said device is placed in a power save mode; and

while said device is in said power save mode

for a first period beginning at a first instance, re-activating said at least one communication subsystem, executing an action relating to a first data link layer connection condition for said network, and then de-activating said at least one communication subsystem; and

for a second period beginning at a second instance, re-activating said at least one communication subsystem, generating and transmitting a frame to a host in said network by said device, and then de-activating said at least one communication subsystem,

wherein

said first period is timed to allow said device to receive a MAC beacon signal;

said second period is set to relate to a frequency of transmission of an Address Resolution Protocol (ARP) request for an Internet Protocol (IP) address for said device;

said first period is repeated on a cycle that is based on a first frequency of occurrence of said data link layer connection condition; and

said second period is repeated on a cycle that is based on a second frequency of occurrence of a network layer connection condition for said network.

2. The method for selectively reducing power consumption of a communication device as claimed in claim 1 , wherein to frame is a unicast frame.

3. The method for selectively reducing power consumption of a communication device as claimed in claim 1 , wherein for said first period:

if said beacon signal indicates broadcast or multicast traffic from said network intended for said device follows said beacon signal, said at least one communication subsystem is de-activated after an end of transmission of said broadcast or multicast traffic; and

if said beacon signal indicates that no broadcast or multicast traffic from said network intended for said device follows said beacon signal, said at least one communication subsystem is de-activated after completion of reception of said beacon signal.

4. The method for selectively reducing power consumption of a communication device as claimed in claim 1 , wherein said first frequency of occurrence is determined from a delivery traffic indication map (DTIM) value in said beacon signal, such that if said DTIM value equals 1, then said first frequency of occurrence is set to be related to a larger DTIM value.

5. The method for selectively reducing power consumption of a communication device as claimed in claim 4 , wherein for said second period, said second frequency of occurrence is set to be shorter than said frequency of transmission of said ARP by at least one host in said network.

6. The method for selectively reducing power consumption of a communication device as claimed in claim 4 , wherein if said DTIM value equals 1, then said first cycle is set to span three or more MAC beacon signal intervals.

7. The method for selectively reducing power consumption of a communication device as claimed in claim 6 , wherein if said DTIM value equals 1, then said first cycle is set to span between three and eight MAC beacon signal intervals.

8. The method for selectively reducing power consumption of a communication device as claimed in claim 1 , wherein for said second action further comprises transmitting a unicast frame to other hosts listed in an ARP cache of said device.

9. The method for selectively reducing power consumption of a communication device as claimed in claim 1 , wherein said second period is repeated on a cycle that is set to be shorter than a frequency of transmission of said ARP request from said network.

10. The method for selectively reducing power consumption of a communication device as claimed in claim 1 , wherein a delivery traffic indication map (DTIM) value is used to indicate a de-activation period for said at least one communication subsystem.

11. The method for selectively reducing power consumption of a communication device as claimed in claim 1 , wherein a clock in said device tracks an elapsed time between receipt of said ARP request and receipt of a next ARP request to determine said second period of said power save mode.

12. The method for selectively reducing power consumption of a communication device as claimed in claim 1 , wherein said first period is extended for a predetermined period when broadcast traffic to said device from said network is being sent to said device to allow said device to receive said broadcast traffic.

13. The method for selectively reducing power consumption of a communication device as claimed in claim 1 , wherein said first period is reduced by a first offset relating to a reactivation time required by said device to re-activate said at least one communication subsystem.

14. A communication device having a power save mode, comprising:

at least one communication subsystem providing transmission and reception of signals with a wireless 802.11-class network;

a microprocessor;

a timer;

a first module to selectively activate and de-activate said at least one communication subsystem when said device is operating in said power save mode; and

a second module to control said first module and said at least one communication subsystem while said device is in said power save mode such that

for a first period beginning at a first instance, said second module initiates said first module to re-activate said at least one communication subsystem, said second module executes an action relating to a data link layer connection requirement for said network, and then said second module initiates said first module to de-activate said at least one communication subsystem; and

for a second period beginning at a second instance, said second module initiates said first module to re-activate said at least one communication, said second module generates and transmits a unicast frame to a host in said network by said device relating to a network layer connection requirement for said network, and then said second module initiates said first module to de-activate said at least one communication subsystem,

wherein

said first period is timed to allow said device to receive a MAC beacon signal;

said second period is set to relate to a frequency of transmission of an Address Resolution Protocol (ARP) request for an Internet Protocol IP address for said device;

said first period is repeated on a cycle that is based on a first frequency of occurrence of said data link layer connection condition; and

said second period is repeated on a cycle that is based on a second frequency of occurrence of a network layer connection condition for said network.

15. The communication device having a power save mode as claimed in claim 14 , wherein for said first period:

if said beacon signal indicates broadcast or multicast traffic from said network intended for said device follows said beacon signal, said at least one communication subsystem is de-activated after an end of transmission of said broadcast or multicast traffic; and

if said beacon signal indicates that no broadcast or multicast traffic from said network intended for said device follows said beacon signal, said at least one communication subsystem is de-activated after an end of transmission of said beacon signal.

16. The communication device having a power save mode as claimed in claim 14 , wherein said first frequency of occurrence is determined from a delivery traffic indication map (DTIM) value in said beacon signal, such that if said DTIM value equals 1, then said first frequency of occurrence is set to be related to a larger DTIM value.

17. The communication device having a power save mode as claimed in claim 14 , wherein said second action further comprises transmitting a unicast frame to other hosts listed in an ARP cache of said device.

18. The communication device having a power save mode as claimed in claim 14 , wherein for said second instance, said second frequency of occurrence is set to be shorter than said frequency of transmission of said Address ARP by at least one host in said network.

19. The communication device having a power save mode as claimed in claim 14 , wherein a delivery traffic indication map (DTIM) value is used to indicate a de-activation period for said at least one communication subsystem.