Method and apparatus for performing idle handoff in a multiple access communication system
AssigneeQUALCOMM Incorporated
InventorEdward G. Tiedemann, Jr.
Life of this patent
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Abstract
A method and apparatus which permits handoffs while the mobile station is in the system access state. This is achieved by providing for channel assignment messages to be sent over the paging channel of a plurality of base stations, which increases the probability of one of the messages getting through. In addition, this assures the mobile station will be able handoff to a different base station and have a traffic channel allocated to it on the new base station without delay. In addition, a method and apparatus which permits the mobile station to be directly assigned into a soft handoff state upon traffic channel assignment.
Claims34
A method for performing idle handoff comprising the steps of:
- measuring, at a mobile station in an idle state, received signal energies from a plurality of base stations;
- compiling, at said mobile station, a first set of base stations with received energies exceeding a predetermined threshold;
- determining a second set of said plurality of base stations with resources to provide communications to said mobile station;
- and
- performing an idle handoff by the mobile station in an access state to a base station common to said first set and said second set.
A method for transitioning a mobile station from an idle state to a soft handoff, comprising:
- transmitting a list containing identifiers of base stations to which the mobile station in an idle state is permitted to perform an idle handoff;
- transitioning the mobile station from an idle state to a soft handoff with a subset of the base stations identified in the list;
- and
- transmitting a traffic channel assignment message indicating traffic channel allocated by each base station of the subset of base stations identified in the list.
A method for transitioning a mobile station from an idle state to a soft handoff, comprising:
- measuring signal energies received from a plurality of base stations at a mobile station in an idle state;
- compiling a first list containing identifiers of base stations with received signal energies exceeding a predetermined threshold at the mobile station;
- determining a second list containing identifiers of base stations to which the mobile station is allowed to perform an idle handoff in accordance with the first list;
- transitioning the mobile station from an idle state to a soft handoff with a subset of the base stations identified by the second list;
- and
- transmitting a traffic channel assignment message indicating traffic channel allocated by each base station identified by the second list.
The method as claimed in 15 wherein said transmitting a traffic channel assignment message indicating traffic channel allocated by each base station identified by the second list from a subset of the plurality of base stations comprises:
- transmitting a traffic channel assignment message via a paging channel.
An apparatus for transitioning a mobile station from an idle state to a soft handoff, comprising:
- a plurality of base stations configured to:
- transmit a list containing identifiers of base stations to which the mobile station in an idle state is permitted to perform an idle handoff;
- and
- a mobile station configured to:
- transition from an idle state to a soft handoff with a subset of base stations identified in the list,
- wherein said plurality of base stations are further configured to:
- transmit a traffic channel assignment message indicating traffic channel allocated by each base station of the subset of base stations identified in the list.
The apparatus as claimed in claim 34 wherein the subset of base stations identified in the list comprises all base stations identified in the list.
An apparatus for transitioning a mobile station from an idle state to a soft handoff, comprising:
- a processor;
- and
- a storage medium coupled to the processor and containing a set of instructions executable by the processor to:
- determine a first list containing identifiers of base stations with resources to provide communications to the mobile station;
- determine a second list containing identifiers of base stations to which the mobile station is allowed to perform an idle handoff in accordance with the first list;
- and
- cause transition of the mobile station from an idle state to a soft handoff with a subset of base stations identified by the second list,
- wherein said processor causes transition of the mobile station from an idle state to a soft handoff with a subset of base stations identified by the second list by executing a set of instructions to:
- cause transmission of a traffic channel assignment message indicating traffic channel allocated by each base station identified in the second list.
Dependencies are inferred from the claim text.