Power saving mode for wireless telephones

• US 6,501,961 B1
• Filed: 10/05/1999
• Issued: 12/31/2002
• Est. Priority Date: 10/05/1999
• Status: Expired due to Term

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kirkpatrick, Jim
• Primary Examiner(s): Vo, Nguyen T.
• Application Number:
  US09/412,346
• Time in Patent Office: 1,183 Days
• Field of Search: 455/553, 455/574, 455/343, 455/552, 455/260, 455/434, 455/515, 395/375, 318/408, 235/454
• US Class Current: 455/553.1
• CPC Class Codes: H04W 52/0225 using monitoring of external events, e.g. the presence of a signal
• CPC Class Codes: H04W 52/028 switching on or off only a part of the equipment circuit blocks
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Reducing power consumption in a dual mode wireless phone, such as a CDMA/AMPS phone, that monitors messages from a forward overhead channel in a standby mode is desirable. It includes turning a receiver off after decoding a pertinent word for the receiver in a particular message and turning it on again some time prior to a next pertinent word. The turn-on is initiated only if necessary to satisfy a redundancy check or if the next word is a beginning of a next message.

Claims

1. A method of reducing power consumption in a dual mode wireless receiver that monitors messages from a forward overhead channel in a standby mode, the method comprising:

decoding a pertinent word for the receiver in a particular message;

deactivating a PLL (Phase-Locked Loop) regulator to turn off the receiver while keeping a main PLL active;

turning on the PLL regulator again some time prior to a next pertinent word, only if necessary to satisfy a redundancy check, otherwise keeping the receiver turned off until the next message; and

repeating the above steps for the next message.

2. The method of claim 1, further comprising:

performing synchronization of the receiver to the particular message.

3. The method of claim 1, wherein the dual mode wireless telephone is a CDMA/AMPS phone.

4. The method of claim 1, wherein the pertinent word is selected from a group comprising type A and type B words.

5. The method of claim 4, wherein the particular message includes five repeating type A words and five repeating type B words interleaved with each other.

6. The method of claim 5, wherein the redundancy check is satisfied if at least three out of five of the pertinent words are matched.

7. The method of claim 1, wherein the redundancy check is satisfied if the pertinent word matches a previously defined control filler word.

8. The method of claim 1, wherein the pertinent word is approximately 4.4 milliseconds in length.

9. The method of claim 8, wherein said some time is approximately one millisecond.

10. A method of operating both modes of a dual mode wireless telephone at reduced power, the method comprising:

deactivating a PLL (Phase-Locked Loop) regulator, while keeping a main PLL active, to turn off a receiver of said telephone after decoding a current relevant packet of data in a message; and

turning on the PLL regulator again at an appropriate amount of time prior to a next relevant packet of data if the combined current and next packets of data in the message do not satisfy a redundancy check, the current packet of data indicates that further decoding is necessary, or the next packet of data is a start of another message.

11. A circuit for providing a sleep state for both modes of a dual mode wireless telephone, said telephone having a receiver for receiving RF signals, the circuit comprising:

a transistor having a base, a collector, and an emitter terminals, said collector terminal coupled to said receiver;

a supply voltage coupled to said collector terminal;

a mode signal providing input to the base terminal of said transistor; and

a sleep signal providing input to the emitter terminal of said transistor, such that when the sleep signal is asserted in a particular mode indicated by the mode signal, the collector of said transistor is driven to turn the receiver off.

12. The circuit of claim 11, wherein the dual mode wireless telephone is a CDMA/AMPS phone.

13. The circuit of claim 12, wherein the mode signal determines whether the phone is in a CDMA or an AMPS mode.

14. The circuit of claim 11, wherein said particular mode indicates a CDMA sleep mode.

15. A dual mode wireless telephone system comprising:

a housing;

electronic components within the housing including a circuit for providing a sleep state for both modes of the dual mode phone, said telephone having a receiver for receiving RF signals, said circuit including;

a transistor having a base, a collector, and an emitter terminals, said collector terminal coupled to said receiver;

a supply voltage coupled to said collector terminal;

a mode signal providing input to the base terminal of said transistor;

a sleep signal providing input to the emitter terminal of said transistor, such that when the sleep signal is asserted in a particular mode indicated by the mode signal, the collector of said transistor is driven to turn the receiver off.

16. A method of operating both modes of a dual mode wireless telephone at reduced power, the method comprising:

providing a first signal level to an input terminal of a transistor to produce a first output to turn off a receiver of said telephone after decoding a current relevant packet of data in a message; and

providing a second signal level to the input terminal to produce a second output to turn the receiver back on at an appropriate amount of time prior to a next relevant packet of data if the combined current and next packets of data in the message do not satisfy a redundancy check, the current packet of data indicates that further decoding is necessary, or the next packet of data is a start of another message.