Apparatus, method and program to optimize battery life in a wireless device

• US 20040002366A1
• Filed: 06/26/2002
• Published: 01/01/2004
• Est. Priority Date: 06/26/2002
• Status: Active Grant

• Current Assignee: Lenovo PC International Limited (Lenovo Group Ltd.)
• Original Assignee: International Business Machines Corporation
• Inventors: Cromer, Daryl Carvis, Locker, Howard Jeffrey, Jakes, Philip John, Ward, James Peter
• Granted Patent: US 7,003,331 B2
• Time in Patent Office: Days
• US Class Current: 455/574
• CPC Class Codes: H04W 52/0261 managing power supply demand, e.g. depending on battery level
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The battery life of batteries of a mobile device operating in a wireless network is optimized by dynamically changing symbol rates and bits per symbol and selecting one for communicating based upon the source providing power to the mobile device.

Claims

1. A mobile device including:

an adapter that provides interface to a wireless network;

a bus controller operatively coupled to the adapter;

I/O devices operatively coupled to the bus controller;

a processor subsystem operatively coupled to the bus controller;

a power supply generating power on multiple power rails; and

a power type detector monitoring the power rails and setting an indicia indicative of the type of power being used by said mobile device.

2. The mobile device of claim 1 further including a power state register wherein the indicia includes bits within said power state register.

3. The mobile device of claim 1 or claim 2 wherein the bus controller includes a PCI bus controller.

4. The mobile device of claim 1 or claim 2 further including a symbol rate register to store a value representing symbol rate at which the mobile device is running.

5. The mobile device of claim 1 or claim 2 wherein the I/O devices include a keyboard, a pointing device and video display.

6. The mobile device of claim 1 or claim 2 further including a flash program storage and DASD operatively coupled to the controller.

7. The mobile device of claim 1 or claim 2 further including a battery operatively coupled to one of the multiple power rails.

8. The mobile device of claim 1 or claim 2 wherein the processor subsystem includes a memory;

a memory controller operatively coupled to said memory; and

a processor operatively coupled to the memory controller.

9. The mobile device of claim 1 or claim 2 wherein the adapter includes an RF transceiver;

TX FIFO operatively coupled to the RF transceiver;

RX FIFO operatively coupled to the RF transceiver; and

MAC (medium access controller) operatively coupled to the TX FIFO and RX FIFO.

10. A method to operate a mobile device running on battery power including the acts of:

monitoring the battery power;

if greater than N, N being a percentage of total power output of said battery, selecting a symbol rate lower than a maximum symbol rate at which said mobile device can operate; and

if said battery power is less than N, selecting a symbol rate which is a minimum at which said mobile device can operate.

11. The method of claim 10 further including the acts of generating a message including the symbol rate selected;

and

forwarding said message.

12. The method of claim 10 or claim 11 wherein N>

(is greater than) 50%.

13. The method of claim 11 or claim 12 further including the act of loading bits in selected symbol envelopes wherein frequency of bits in a symbol envelope is proportional to frequency of the selected symbols.

14. A method of operating a mobile device including the acts of:

providing a plurality of power rails to supply power to said mobile device;

providing a register for storing information identifying the power rail supplying power to said mobile device;

monitoring the power rails;

setting a bit in said register to identify the power rail supplying power to said mobile device; and

selecting a symbol rate to transmit and receive data based upon the power rail that supplies power to said mobile device.

15. The method of claim 14 further including the act of setting an indicia indicating the selected symbol rate.

16. The method of claim 14 or claim 15 wherein the plurality of power rails includes AUX power, DC power and battery power.

17. The method of claim 14 or claim 15 further including the acts of generating a request message including the selected symbol rate;

and

transmitting said message to an Access Point to which the mobile device is attached.

18. The method of claim 17 further including the acts of receiving in said mobile unit a response message with information confirming permission to communicate at a particular symbol rate and thereafter using the particular symbol rate to communicate with the Access Point.

19. An Access Point device including:

a first adapter that provides an interface to a wired network;

a subassembly that provides an interface to a wireless network;

said subassembly being operable to generate messages having different symbol rate and different number of bits per symbol envelope;

a system controller;

a first bus operatively coupling the system controller to the subassembly; and

a second bus operatively coupling the system controller to the first adapter.

20. The Access Point of claim 19 wherein the subassembly includes N adapters, N greater than 1, wherein each of the N adapters operate at different symbol rates and different number of bits per symbol.

21. A method including the acts of:

receiving in an Access Point device a request to operate at a requested symbol rate;

determining symbol rates available to communicate in said Access Point; and

accepting the request if any of the available symbol rates are compatible with the requested symbol rate.

22. The method of claim 21 further including the acts of generating a message including information accepting a requested symbol rate;

and transmitting the message.

23. A method including the acts of:

receiving in an Access Point device a request to operate at a requested symbol rate;

determining symbol rates available to communicate in said Access Point; and

denying the request if none of the available signal rates is compatible with the requested symbol rate.

24. The method of claim 23 further including the acts of generating a message including information denying a requested symbol rate;

and transmitting the message.

25. A method including the acts of:

determining an Access Point with which a mobile device wishes to communicate;

determining a power source on which said mobile device is running; and

selecting a symbol rate with which said mobile device will communicate based upon the type of power that said mobile unit is using.

26. The method of claim 25 wherein the determining act further includes executing in said mobile device a process compatible with the process set forth in IEEE 802.11 specification for wireless network for wireless device to register with an Access Point.

27. The method set forth in claim 25 wherein the selecting act further includes monitoring outputs from power sources provided in said mobile device if one of the outputs indicate a first power source selecting a maximum symbol rate.

28. The method of claim 27 wherein first power source includes DC power.

29. The method of claim 27 wherein first power source includes AUX power.

30. The method set forth in claim 25 wherein the selecting act further includes monitoring outputs from power sources provided in said mobile device if one of the outputs indicate a second power source selecting a symbol rate less than maximum.

31. The method of claim 30 wherein the second power source includes battery power.

32. The method of claim 31 further including the acts of:

testing the battery power to determine output level,

if output level>

(greater than) 50% revert to intermediate symbol rate and if output level<

(less than) 50% revert to minimum symbol rate.

33. A computer program product including:

a computer readable medium on which computer program is recorded, said computer program including a first code module that establishes a link between a mobile device and an Access Point;

a second code module that determines a power source on which said mobile device is running; and

a third code module to select a symbol rate based upon the type of power used to operate said mobile device.

34. An adapter including:

a transceiver to communicate with a wireless network;

a first buffer to buffer data to be transmitted into the wireless network operatively coupled to the transceiver;

a second buffer for receiving data from the network operatively coupled to the transceiver;

a system interface for coupling to a system bus;

a Medium Access Controller (MAC) operatively coupled to the system interface and the first buffer and the second buffer respectively; and

symbol generator that provides variable symbol in which data is packaged and forwarded to the wireless network.

35. The adapter of claim 34 further including a power antenna operatively coupled to the transceiver.