Selection of communication channel in a digital cordless telephone

• US 5,758,263 A
• Filed: 12/07/1995
• Issued: 05/26/1998
• Est. Priority Date: 12/07/1995
• Status: Expired due to Term

• Current Assignee: Quarterhill Inc. (f/k/a Wi-LAN Inc.)
• Original Assignee: Rockwell International Corporation
• Inventors: Berger, Douglas M., Walley, John S.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Armstrong, Darnell R.
• Application Number:
  US08/568,871
• Time in Patent Office: 901 Days
• Field of Search: 455/33.1, 455/54.1, 455/56.1, 455/67.1, 455/67.4, 455/126, 455/127, 455/134, 455/161.3, 455/161.1, 455/226.2, 455/226.1, 455/34.1, 455/502, 455/507 , 455/510, 455/515, 455/517, 455/509, 455/512, 379/58, 379/60, 379/61, 379/102.7, 379/100.6
• US Class Current: 455/67.14
• CPC Class Codes: H04B 17/18 Monitoring during normal operation
• CPC Class Codes: H04M 1/72511 Searching for available channels
• CPC Class Codes: H04M 1/73 Battery saving arrangements
• CPC Class Codes: H04M 2250/08 home cordless telephone systems using the DECT standard
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method for testing a communication link between first and second components of a system, which components communicate via a selected one of a plurality of broadcast channels, the second component being powered by a self-contained power source, the method comprising: causing the first component to scan a plurality of the broadcast channels in sequence in a receiving mode during a scanning period and to broadcast a test signal over the selected channel during the scan; and maintaining the second component in an inactive state in which energy consumption is minimized and in which the second component is unresponsive to broadcast signals during a major part of the scanning period, placing the second component in an active state in which the second component can detect the test signal during a time when the test signal is being broadcast, and causing the second component to broadcast a response signal upon detection of the test signal.

Claims

1. A low-power method for frequently enabling while less frequently testing a communication link between first and second components of a system over a selected channel, which components communicate via a selected one of a plurality of broadcast channels, the second component being powered by a self-contained power source, said method comprising:

the second component maintaining an inactive state in which energy consumption is minimized and in which the second component is unresponsive to broadcast signals during a major part of successive scanning periods, each scanning period comprising a plurality of time intervals corresponding to the plurality of broadcast channels, a selected one of the plurality of time intervals corresponding to the selected channel;

second component periodically entering an active state during the selected time interval corresponding to the selected channel during each of the successive scanning periods in order to detect a communication from the first component with minimum energy consumption by periodically monitoring only the selected channel;

the first component periodically broadcasting a channel maintenance signal over the selected channel during a particular one of a plurality of successive scanning periods;

the second component detecting the channel maintenance signal when the channel maintenance signal is being broadcast by the first component during the particular one of the plurality of scanning periods;

the second component broadcasting a response signal upon detection of the channel maintenance signal during the particular one of the plurality of scanning periods; and

the first component detecting the response signal broadcast by the second component and, based thereon, maintaining the selected channel whereby the second component may continue to monitor only the selected channel when it periodically enters an active state.

2. A method as defined in claim 1, comprising the further step of the first component responding to a reception of the response signal by broadcasting a confirmation signal while the second component is in the active state.

3. A method as defined in claim 1 in combination with a method for selecting a new broadcast channel when the channel maintenance signal periodically broadcast by the first component on the selected channel is not detected by the second component, said method for selecting a new broadcast channel comprising the steps of:

the first component scanning the plurality of broadcast channels for transmissions from the second component during the corresponding plurality of time intervals during successive scanning periods;

the second component transmitting a channel test signal over a second broadcast channel different from the selected channel throughout at least a scanning period so that the channel test signal can be received at the first component; and

the first component making the second broadcast channel the selected channel when the channel test signal is detected at the first component.