Method and apparatus for hard handoff in a CDMA system
First Claim
1. In a communications network in which a network user communicates through a remote unit with another user via at least one base station, said communications network including a first mobile switching center for controlling communications through a first set of base stations including a first base station, a method for directing communications between said remote unit and said first base station comprising the steps of:
- storing at said remote unit a list of active base stations comprising an entry corresponding to each base station with which active communication is established and wherein said first base station has an entry on said list of active base stations;
measuring, at said first base station, a round trip delay of a first active communication signal between said first base station and said remote unit; and
initiating a handoff of said first active communication signal if said round trip delay of said first active communication exceeds a threshold if said first base station is designated as a boundary base station.
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Accused Products
Abstract
In a communications network, a network user communicates through a remote unit with another user via at least one base station. The communications network includes a first mobile switching center which controls communications through a first set of base stations including a first base station. The remote unit stores a list of active base stations which has an entry corresponding to each base station with which active communication is established. The first base station has an entry on the list of active base stations. The first base station measures a round trip delay of an active communication signal between the first base station and the remote unit. A handoff of the active communication signal is initiated if the round trip delay of the active communication exceeds a threshold if the first base station is designated as a reference base station. Alternatively, the remote unit also stores a list of candidate base stations comprising an entry corresponding to each base station through which active communication may be possible but is not established. A handoff of the active communication signal is initiated if the list of candidate base stations comprises an entry corresponding to a triggering pilot signal.
145 Citations
24 Claims
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1. In a communications network in which a network user communicates through a remote unit with another user via at least one base station, said communications network including a first mobile switching center for controlling communications through a first set of base stations including a first base station, a method for directing communications between said remote unit and said first base station comprising the steps of:
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storing at said remote unit a list of active base stations comprising an entry corresponding to each base station with which active communication is established and wherein said first base station has an entry on said list of active base stations; measuring, at said first base station, a round trip delay of a first active communication signal between said first base station and said remote unit; and initiating a handoff of said first active communication signal if said round trip delay of said first active communication exceeds a threshold if said first base station is designated as a boundary base station. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. In a communications network in which a network user communicates through a remote unit with another user via at least one base station, said communications network including a first mobile switching center for controlling communications through a first set of base stations including a first base station, a method for directing communications between said remote unit and said first base station and to a second base station comprising the steps of:
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storing at said remote unit a list of active base stations comprising an entry corresponding to each base station with which active communication is established and wherein said first base station has an entry on said list of active base stations and wherein said first base station is a reference base station; storing at said remote unit a list of candidate base stations comprising an entry corresponding to each base station through which active communication may be established; and initiating a handoff of an active communication signal from said first base station to said second base station if a pilot signal of said second base station on said list of candidate base stations corresponds to a triggering pilot signal. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification