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

• US 7,003,331 B2
• Filed: 06/26/2002
• Issued: 02/21/2006
• Est. Priority Date: 06/26/2002
• Status: Active Grant

• Current Assignee: Lenovo PC International Limited (Lenovo Group Ltd.)
• Original Assignee: Lenovo Singapore Pte Limited (Lenovo Group Ltd.)
• Inventors: Cromer, Daryl Carvis, Locker, Howard Jeffrey, Jakes, Philip John, Ward, James Peter
• Primary Examiner(s): Kincaid, Lester G.
• Assistant Examiner(s): DOAN, PHUOC HUU
• Application Number:
  US10/180,048
• Publication Number:
  US 20040002366A1
• Time in Patent Office: 1,336 Days
• Field of Search: 455/448, 455/574, 455/572, 370/338, 370/208, 375/346, 349/143
• 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;

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

a symbol rate generator that generates symbols at a symbol rate, each symbol including a number of bits per symbol, the symbol rate and the number of bits per symbol determined by the type of power being used; and

wherein the number of bits per symbol is inversely proportional to the symbol rate and adjusted in order to maintain a constant throughput; and

wherein the mobile device communicates with an Access Point that is adapted to;

receive a request from the mobile device to operate at a requested symbol rate;

determine symbol rates available to communicate in said Access Point;

accept the request if any of the available symbol rates are compatible with the requested symbol rate; and

deny the request if none of the available symbol rates are compatible with the requested symbol rate.

2. The mobile device of claim 1 further including a power source register wherein the indicia includes bits within said power source register, the bits identifying whether the type of power is DC power, AUX power, or battery power.

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 the symbol rate at which the mobile device is running, the value based upon the type of power being used.

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

6. The mobile device of claim 1 or claim 2 further including a flash program storage and a 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;

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 for generating symbols lower than a maximum symbol rate at which said mobile device can operate;

if said battery power is less than N, selecting a symbol rate for generating the symbols which is a minimum at which said mobile device can operate;

loading a number of bits per symbol in each of the generated symbols; and

wherein the number of bits per symbol is inversely proportional to the symbol rate and adjusted in order to maintain a constant throughput; and

wherein the mobile device communicates with an Access Point that is adapted to;

receive a request from the mobile device to operate at a requested symbol rate;

determine symbol rates available to communicate in said Access Point;

accept the request if any of the available symbol rates are compatible with the requested symbol rate; and

deny the request if none of the available symbol rates are compatible with the requested symbol rate.

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. 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;

selecting a symbol rate and a number of bits per symbol to transmit and receive data based upon the power rail that supplies power to said mobile device; and

wherein the number of bits per symbol is inversely proportional to the symbol rate and adjusted in order to maintain a constant throughput; and

wherein the mobile device communicates with an Access Point, the access point adapted to;

receive a request from the mobile device to operate at a requested symbol rate;

determine symbol rates available to communicate in said Access Point;

accept the request if any of the available symbol rates are compatible with the requested symbol rate; and

deny the request if none of the available symbol rates are compatible with the requested symbol rate.

14. The method of claim 13 further including the act of setting an indicia indicating the selected symbol rate.

15. The method of claim 13 or claim 14 wherein the plurality of power rails includes AUX power, DC power, and battery power.

16. The method of claim 13 or claim 14 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.

17. The method of claim 16 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.

18. 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; and

wherein the Access Point device is adapted to;

receive a request from the mobile device to operate at a requested symbol rate;

determine symbol rates available to communicate in said Access Point;

accept the request if any of the available symbol rates are compatible with the requested symbol rate; and

deny the request if none of the available symbol rates are compatible with the requested symbol rate.

19. The Access Point of claim 18 wherein the subassembly includes N adapters, N greater than 1, wherein each of the N adapters operate at a different symbol rates and different number of bits per symbol.

20. A method including the acts of:

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

receive a request from the mobile device to operate at a requested symbol rate;

determine symbol rates available to communicate in said Access Point;

accept the request if any of the available symbol rates are compatible with the requested symbol rate; and

deny the request if none of the available symbol rates are compatible with the requested symbol rate;

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

selecting a symbol rate and a number of bits per symbol with which said mobile device will communicate based upon the type of power that said mobile unit is using; and

wherein the number of bits per symbol is inversely proportional to the symbol rate and adjusted in order to maintain a constant throughput.

21. The method of claim 20 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.

22. The method set forth in claim 20 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.

23. The method of claim 22 wherein the first power source includes DC power.

24. The method of claim 22 wherein the first power source includes AUX power.

25. The method set forth in claim 20 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.

26. The method of claim 25 wherein the second power source includes battery power.

27. The method of claim 26 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.

28. 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, the Access Point adapted to;

receive a request from the mobile device to operate at a requested symbol rate;

determine symbol rates available to communicate in said Access Point;

accept the request if any of the available symbol rates are compatible with the requested symbol rate; and

deny the request if none of the available symbol rates are compatible with the requested symbol rate;

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

a third code module to select a symbol rate and a number of bits per symbol based upon the type of power used to operate said mobile device; and

wherein the number of bits per symbol is inversely proportional to the symbol rate and adjusted in order to maintain a constant throughput.

29. 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;

symbol generator that provides variable symbol at a symbol rate in which data is packaged at a number of bits per symbol and forwarded to the wireless network;

wherein the number of bits per symbol is inversely proportional to the symbol rate and adjusted in order to maintain a constant throughput; and

wherein the adapter is associated with an Access Point that is adapted to;

receive a request from the mobile device to operate at a requested symbol rate;

determine symbol rates available to communicate in said Access Point;

accept the request if any of the available symbol rates are compatible with the requested symbol rate; and

deny the request if none of the available symbol rates are compatible with the requested symbol rate.

30. The adapter of claim 29 further including a power antenna operatively coupled to the transceiver.