Communication system employing multiple handoff criteria
First Claim
1. A method for high speed data transmission from one or more base stations to a mobile station comprising:
- measuring the quality of forward link signals from one or more base stations;
adding one or more base stations to an active set when the quality of the forward link signal from the base station exceeds a higher threshold;
adding one or more sectors of one or more base stations to an active set when the quality of the forward link signal from each sector exceeds a lower threshold and at least one other sector of that sector'"'"'s base station is in the active set; and
transmitting from one base station having the highest measured forward link signal quality to the mobile station during a time slot when that measured forward link signal quality meets certain criteria; and
transmitting from one or more base stations in soft handoff to the mobile station during a time slot when the highest measured forward link signal quality does not meet certain criteria.
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Accused Products
Abstract
Disclosed herein is a communication system which manages guarantee of service (GOS) requirements for various users while efficiently managing backhaul network traffic and optimizing overall system capacity. In one aspect, armed handoff is used to transmit forward link data from a single base station to a particular mobile station as long as certain minimum requirements are met, such as minimum data throughput, minimum data rate, and GOS requirements. If these criteria are not met, soft and softer handoff can be employed to transmit forward link data from one or more base stations to a particular mobile station until the conditions for armed handoff are met. In another aspect, the test to add a base station sector to the active set differs based on whether other sectors of that base station already exist in the active set. The test is less stringent when a sector is not the first of its base station to enter the active set, and more stringent when it is the first.
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Citations
21 Claims
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1. A method for high speed data transmission from one or more base stations to a mobile station comprising:
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measuring the quality of forward link signals from one or more base stations; adding one or more base stations to an active set when the quality of the forward link signal from the base station exceeds a higher threshold; adding one or more sectors of one or more base stations to an active set when the quality of the forward link signal from each sector exceeds a lower threshold and at least one other sector of that sector'"'"'s base station is in the active set; and transmitting from one base station having the highest measured forward link signal quality to the mobile station during a time slot when that measured forward link signal quality meets certain criteria; and transmitting from one or more base stations in soft handoff to the mobile station during a time slot when the highest measured forward link signal quality does not meet certain criteria. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for high speed data transmission from one or more sectored base stations to a mobile station comprising:
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measuring the quality of forward link signals from one or more sectors of one or more base stations; adding one or more of the sectors of one or more base stations to an active set when the quality of the forward link signal from each sector exceeds a higher threshold; and adding one or more of the sectors of one or more base stations to an active set when the quality of the forward link signal from each sector exceeds a lower threshold and at least one other sector of that sector'"'"'s base station is in the active set. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A method for high speed data transmission from one or more base stations to a mobile station comprising:
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measuring the quality of forward link signals from one or more base stations; selecting one base station according to the measured quality of forward link signals from one or more base stations; when the measured quality of the forward link signal from the selected base station meets a criterion, where the criterion consists of adding one or more base stations to an active set when the quality of the forward link signal from the base station exceeds a higher threshold; adding one or more sectors of one or more base stations to an active set when the quality of the forward link signal from each sector exceeds a lower threshold and at least one other sector of that sector'"'"'s base station is in the active set; and
;sending a data request message to the selected base station; and transmitting data from the selected base station to the mobile station at a rate in accordance with the measured quality of the forward link signal from the selected base station; and when the measured quality of the forward link signal from the selected base station does not meet a criterion; selecting one or more additional base stations such that the combined quality of forward link signals of the first selected base station and the additional one or more base stations meets the criterion; and transmitting data from the selected base station and the additional one or more base stations to the mobile station at a rate in accordance with the combined quality of the forward link signal from the selected and additional base stations. - View Dependent Claims (19, 20)
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21. A communications system, comprising:
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a plurality of base stations which transmit respective pilots and respective code channels comprising a forward traffic channel; a mobile station which has the plurality of base stations assigned to an active set thereof, comprising; a diversity receiver which measures respective signal qualities of the pilots; a processor which produces a signal quality standard, prepares a message directing one of the base stations to transmit data on its respective fox-ward traffic channel when the quality of the pilot of the one base station equals or surpasses the standard, and prepares a message directing more than one base station to transmit data simultaneously on their respective forward traffic channels when the quality of a single pilot of any of the base stations does not equal or surpass the standard; and a transmitter which transmits the message to the system controller via the plurality of base stations; a system controller communicatively connected to the plurality of base stations and maintaining data queues for the mobile station'"'"'s forward traffic data in those base stations contained in the mobile station'"'"'s active set; wherein the one base station receives, and transmits in response to, a message directing the one base station to transmit data from its data queue on its respective forward traffic channel; and wherein the system controller receives a message directing more than one base station to transmit data simultaneously on their respective forward traffic channels and directs the respective base stations accordingly.
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Specification