Handover based on measured time of signals received from neighboring cells

• US 5,722,072 A
• Filed: 03/20/1995
• Issued: 02/24/1998
• Est. Priority Date: 03/21/1994
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Thomas, Howard, Crichton, Paul, Oberoi, Rupinder Singh
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Kincaid, Lester G.
• Application Number:
  US08/406,439
• Time in Patent Office: 1,072 Days
• Field of Search: 455/33.1, 455/33.2, 455/33.3, 455/34.2, 455/54.1, 455/54.2, 455/56.1, 455/33.4, 455/67.1, 455/226.2, 379/60
• US Class Current: 455/437
• CPC Class Codes: H04W 36/04 Reselecting a cell layer in multi-layered cells

Abstract

A method for determining a handover for a mobile station in a multicellular communication system including the steps of measuring received signal parameters received from a serving cell and a plurality of neighboring cells, comparing received signal parameters with a variable threshold value for each of the plurality of neighbor cells, measuring the amount of time, or the number of times, the received signal parameters are above the threshold value for each of the plurality of neighbor cells, and determining handover based on the measurement.

Claims

1. A method for determining a handover candidate in at least one mobile unit communicating with a base station of a cellular radio communication system including a serving cell and a plurality of neighboring cells, wherein the serving cell and the neighboring cells comprise at least one umbrella cell and a plurality of microcells, each cell having a respective base station, the method including the steps of:

measuring received signal parameters for at least some of the neighboring cells of the plurality of neighboring cells;

starting a timer associated with a particular neighboring cell of said at least some of the neighboring cells when the particular neighboring cell has a measured received signal parameter that exceeds a first predetermined threshold;

after a first predetermined period, determining whether the measured received signal parameter for the particular neighboring cell exceeds a second predetermined threshold to identify a requirement for a handover; and

in response to the second predetermined threshold being exceeded, generating a prioritized handover candidate list for the at least some of the neighboring cells by applying differing weighting factors between the serving cell and each of the at least some of the neighboring cells, the weighting factors being based on;

received signal strength levels of the at least some of the neighboring cells;

power budget margins between the serving cell and the at least some of the neighboring cells; and

elapsed time since starting the timer in the at least some of the neighboring cells.