Method and apparatus for enabling soft handoff in an OFDMA-based communication system
First Claim
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1. A method of managing data transmission during a soft handoff in a communication system, the method comprising the steps of:
- generating, from a mobile station, a pilot signal strength report for each sector of a base station in communication with the mobile station, wherein the communication system is an orthogonal frequency division multiplexing (OFDM)-based system;
receiving, at the mobile station, a plurality of soft handoff groups from the base station in accordance with the pilot signal strength report generated by the mobile station, wherein at least one of the soft handoff groups contains more than one sector;
measuring, by the mobile station, a combined pilot signal strength of each combined pilot signal;
selecting, by the mobile station, a desired soft handoff group in accordance with the measured combined pilot signal strengths;
updating member sectors in the mobile station'"'"'s current soft handoff group responsive to the desired soft handoff group;
wherein the mobile station communicates the desired soft handoff group to the base station using a reverse channel quality indicator (CQI) channel;
assigning a covering sequence for the reverse CQI channel for each soft handoff group that the base station forms for the mobile station;
communicating to the mobile station the covering sequence for each soft handoff group;
covering the reverse CQI channel by the mobile station with the covering sequence associated with the desired soft handoff group; and
transmitting the reverse CQI channel by the mobile station setting a transmit power for the desired soft handoff group.
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Abstract
A method of enabling a soft handoff in a communication system, wherein the communication system includes a plurality of sectors and each of the plurality of sectors includes at least one base station is disclosed. The method includes: providing at least one mobile station; setting identical resources for serving the mobile station from each of the plurality of base stations in each sector; designating at least a plurality of base stations in at least one sector to participate a soft handoff; and performing a soft handoff.
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Citations
17 Claims
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1. A method of managing data transmission during a soft handoff in a communication system, the method comprising the steps of:
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generating, from a mobile station, a pilot signal strength report for each sector of a base station in communication with the mobile station, wherein the communication system is an orthogonal frequency division multiplexing (OFDM)-based system; receiving, at the mobile station, a plurality of soft handoff groups from the base station in accordance with the pilot signal strength report generated by the mobile station, wherein at least one of the soft handoff groups contains more than one sector; measuring, by the mobile station, a combined pilot signal strength of each combined pilot signal; selecting, by the mobile station, a desired soft handoff group in accordance with the measured combined pilot signal strengths; updating member sectors in the mobile station'"'"'s current soft handoff group responsive to the desired soft handoff group; wherein the mobile station communicates the desired soft handoff group to the base station using a reverse channel quality indicator (CQI) channel; assigning a covering sequence for the reverse CQI channel for each soft handoff group that the base station forms for the mobile station; communicating to the mobile station the covering sequence for each soft handoff group; covering the reverse CQI channel by the mobile station with the covering sequence associated with the desired soft handoff group; and transmitting the reverse CQI channel by the mobile station setting a transmit power for the desired soft handoff group. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A base station for transmitting data to a mobile station in soft handoff, the base station comprising:
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a scheduler adapted to receive from a particular mobile station a desired soft handoff group request in accordance with a combined pilot signal strength comparison of potential soft handoff groups measured by the mobile station, wherein at least one of the soft handoff groups contains more than one sector, the scheduler adapted to assign, in accordance with the desired handoff group request, resources of a plurality of sectors that participate in soft handoff for transmission of particular data to the particular mobile station; a plurality of remote modules, each containing a radio frequency processing unit for at least one sector of the base station, wherein the base station is in an orthogonal frequency division multiplexing (OFDM)-based system; a main module that comprises base band processing units for the plurality of remote modules of at least one cell; a communicative connection between the plurality of remote modules and the main module; reporting a combined channel quality indicator (CQI) with the combined pilot strength from member sectors of the desired soft handoff group to the base station by the mobile station; and selecting a modulation and coding scheme (MCS) by the base station for the data transmission to the mobile station in accordance with the combined CQI report from the mobile station. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification