Enhanced power saving method for hand-held communications system and a hand-held communications system therefor

• US 5,627,882 A
• Filed: 05/26/1994
• Issued: 05/06/1997
• Est. Priority Date: 06/02/1993
• Status: Expired due to Term

• Current Assignee: ST-Ericcson SA (Telefonaktiebolaget LM Ericsson)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Chien, Cheng-Tung, But, Chiu-Hong, Chen, Chang-Wen
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): Maung, Nay Aung
• Application Number:
  US08/249,428
• Time in Patent Office: 1,076 Days
• Field of Search: 379/61, 379/58, 379/59, 455/38.3, 455/127, 455/343, 455/161.1, 455/161.2, 340/825.44
• US Class Current: 455/464
• CPC Class Codes: H04M 1/73 Battery saving arrangements
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 52/0232 according to average transmission signal activity
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

An enhanced power saving method for operating a battery powered hand-held communication system, particularly a cordless phone system, and the communication system constructed in accordance with the power saving method are described. The power saving method consists of an algorithm which divides the standby time of the communication system into a scanning mode and a sleep mode having several different levels to allow the system to enter the scanning mode intermittently. Each level of the sleep mode corresponds to a given length of delay time between two successive scanning periods. The communication system enters different levels of the sleep mode in accordance with the standby time history. The more standby time that passes, the longer the sleep time for the level that the system may enter. This reduces the scan rate when the system is not used for a long period.

Claims

1. A power saving method for a cordless communication system wherein the cordless communication system comprises a receiver to scan and receive signals from a surrounding air, which receiver enters a period of a standby mode when no signal is coming in to be received thereby and which is activated to scan the signals from the surrounding air in accordance with preset scan rates and deactivated for a length of preset delay time to reduce power consumption in an alternate fashion within the standby mode period, said power saving method comprising:

dividing the standby period into a number of successive time zones;

establishing a delay level for each of said time zones, each delay level being associated with a delay time period;

setting a scan rate for each of said delay levels;

continuously allowing the receiver to be activated in accordance with the delay level and the scan rate associated with a current time zone of said time zones to establish a standby time history of the receiver;

recording the standby time history and comparing the standby time history with the definition of said time zones to determine which of said time zones the receiver is operating in;

updating the standby time history to allow the receiver to enter a next time zone next to the current time zone that the receiver was originally operating in so as to scan with the scan rate and to sleep for the delay time associated with the next time zone when the current time zone is exceeded; and

repeating the comparing and updating procedures until being interrupted by an attempt to establish communication via the cordless communication system.

2. The method as claimed in claim 1, wherein the standby period is divided into at least three time zones of which a first time zone has the highest scan rate and the least delay time, a second time zone has an intermediate scan rate and an intermediate delay time and a third time zone has the lowest scan rate and the greatest delay time.

3. The method as claimed in claim 2, wherein said receiver is reset to the first time zone when the standby history is interrupted by an attempt to establish communication.

4. In a multiple channel access auto-scan cordless phone system having multiple channels controlled by a central processing unit, a wireless communication device comprising a decoding device for confirmation of signals received by the phone system comprising:

receiver means for receiving signals from the phone system;

memory means for storing therein an identification for each of the multiple channels of the phone system;

checker means for comparing a code carried by the signals with the identifications so that when the code matches with one of the identifications, an actuating signal is generated to wake up the central processing unit of the phone system to process the received signals;

a synthesizer controller which provides each of the multiple channels with a given communication frequency; and

power saving circuit means for, when the phone system is in a standby mode for which a number of successive time zones are defined, providing the phone system with a corresponding number of different and time-based scan rates and delay time periods associated with the time zones to allow the phone to intermittently scan for the signals from the surrounding air in accordance with a respective one of the scan rates and to sleep for a period of a respective one of the delay times associated with a particular one of the time zones.

5. The wireless communication device as claimed in claim 4 wherein, said power saving circuit means comprises:

an accumulator for up-counting the number of signal scannings conducted by the phone system;

a standby history recorder which has the respective scan rates and the respective delay time periods for said time zones built therein to allow the phone system to enter a next time zone adjacent to said particular one of the time zones in response to the accumulator so as to change the operative scan rate and the operative delay time period in accordance with a counting result provided by the accumulator; and

a sleep time controller for controlling the sleeping and scanning modes of the phone system during the standby mode in accordance with the time zones set in the standby history recorder.

6. In a power saving cordless communication system, comprising:

receiver means for scanning an incoming signal comprising at least an identification portion and an audio portion during a standby period of the system at a scan rate and receiving the incoming signal as a received signal, said standby period being divided into a number of successive time zones, the receiver means moving from a current time zone to a next time zone with time during the standby period;

decoding means for decoding and identifying the identification portion of the received signal;

audio and control means for processing the audio portion of the received signal and sending out the processed audio portion together with the identification portion; and

transmitter means for transmitting outgoing signals;

the improvement comprising an improved decoding means including;

identifying means for checking the identification portion of the received signal with an identification code associated with the system; and

power saving means for providing said receiver means with a number of different scan rates respectively associated with the time zones of the standby period so as to allow said receiver means to scan incoming signals with a particular scan rate associated with the current time zone of said time zones which said receiver means is currently operating in.