Apparatus and method for alternative radiotelephone system selection

• US 5,260,988 A
• Filed: 02/06/1992
• Issued: 11/09/1993
• Est. Priority Date: 02/06/1992
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: D'Avello, Robert F., Schellinger, Michael J., Krolopp, Robert K.
• Primary Examiner(s): Ng, Jin F.
• Assistant Examiner(s): Cumming, William D.
• Application Number:
  US07/832,063
• Time in Patent Office: 642 Days
• Field of Search: 379/59, 379/61, 379/56, 379/58, 379/62, 379/63, 455/7, 455/11.1, 455/31.1, 455/33.1, 455/54.1, 455/73, 455/130, 455/150, 455/179, 455/56.1
• US Class Current: 455/552.1
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 84/105 PBS [Private Base Station] network H04W84/12 - H04W84/16 take precedence

Abstract

A dual mode cellular cordless portable radiotelephone preferentially selects the cordless base station over the cellular system when in range of the cordless base station. When the cordless cellular portable is operating in the cellular mode, the radio channel associated with the cordless base station is sampled for a predetermined time. When a signal on the sampled cordless base station channel is detected, the cordless portable moves to the cordless mode and remains in the cordless mode for as long as the signal quality of the signal on the cordless base station channel exceeds a predetermined value.

Claims

1. A radiotelephone apparatus which transmits and receives messages preferably on a first radiotelephone system having a limited radio coverage area and which alternatively transmits and receives messages on a second radiotelephone system having a wide radio coverage area, the radiotelephone apparatus comprising:

means for determining the availability of a radio channel associated with the first radiotelephone system;

means for monitoring for a first predetermined period of time a radio channel associated with the second radiotelephone system when said radio channel associated with the first radiotelephone system has been determined to be unavailable;

means for sampling for a second predetermined period of time a signal quality of a signal on said radio channel associated with the first radiotelephone system following said first predetermined period of time; and

means for monitoring for as long as said signal quality of said signal exceeds a predetermined value said radio channel associated with the first radiotelephone system.

2. A method of alternative system selection for a radiotelephone apparatus which transmits and receives messages preferably on a first radiotelephone system having a limited radio coverage area and which alternatively transmits and receives messages on a second radiotelephone system having a wide radio coverage area, the method comprising the steps of:

determining the availability of a radio channel associated with the first radiotelephone system;

monitoring for a first predetermined period of time a radio channel associated with the second radiotelephone system when said radio channel associated with the first radiotelephone system has been determined to be unavailable;

sampling for a second predetermined period of time a signal quality of a signal on said radio channel associated with the first radiotelephone system following said first predetermined period of time; and

monitoring for as long as said signal quality of said signal exceeds a predetermined value said radio channel associated with the first radiotelephone system.