Antenna adaptation to manage the active set to manipulate soft hand-off regions

• US 7,113,786 B2
• Filed: 03/10/2003
• Issued: 09/26/2006
• Est. Priority Date: 03/08/2002
• Status: Expired due to Fees

• Current Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Original Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Inventors: Proctor, James A. Jr.
• Primary Examiner(s): Bui, Bing Q.
• Application Number:
  US10/386,392
• Publication Number:
  US 20040127220A1
• Time in Patent Office: 1,296 Days
• Field of Search: 455/151.1, 455/277.1, 455/436, 455/442
• US Class Current: 455/442
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection

Abstract

A method of managing the number of base station engaged in soft hand-off in a mobile communication system. The method involves manipulating a subscriber based directional antenna so as to control the number of base transceiver stations, pilot channels, beacon signals or other signals detected to be used in soft hand-off processing. The adaptive antennas are modified to manage the number of active set members, such as by manipulating direction, beamwidth, or other antenna parameters.

Claims

1. A method for managing an active set of radio channels used in soft hand-off processing, the method carried out in a remote unit having an adaptive antenna, the method comprising the steps of:

determining an initial list of members for the active set by detecting an existence of at least two pilot channel signals in a vicinity of the remote unit;

making a change in an operating state of the adaptive antenna; and

requalifying the active set with the changed adaptive antenna operating state.

2. A method as in claim 1 wherein the adaptive antenna is a directional antenna array.

3. A method as in claim 2 wherein the adaptive antenna is a phased array.

4. A method as in claim 3 wherein the adaptive antenna uses multiple receivers and signal combiners.

5. A method as in claim 1 additionally comprising the steps of:

determining a reliability parameter for selecting members of the active set;

designating a selected one of the reliability parameters as sufficient to maintain a reliable connection; and

upon determining that more than one active set member is a reliable connection, changing operational state of the adaptive antenna to reduce a number of radio channel signals received.

6. A method as in claim 5 wherein the measure of reliability is selected from a group consisting of received signal strength indication, correlated power, and measurements of signal to noise ratio.

7. A method as in claim 1 additionally comprising the step of, when a number of members of the active set is less than a desired number:

adjusting the antenna state to capture additional radio signals to be possible members of the active set; and

requalifying the active set members.

8. A method as in claim 1 additionally comprising the step of, if a member of the active set is not reliable:

selecting a new setting for the adaptive antenna; and

requalifying active set members.

9. A method as in claim 1 additionally comprising the step of, when members of the active set are deemed unreliable:

steering the antenna such that additional radio signals are detected.

10. A method as in claim 1 additionally comprising the step of:

if candidate pilot channel signals are determined unreliable but of sufficient quality, periodically selecting a new antenna operating state such that criteria for receiving at least one radio signal is not satisfied.