Soft handoff in OFDMA system
First Claim
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1. A method for facilitating soft handoffs in an orthogonal frequency division multiplexing access (OFDMA) system, the method comprising:
- generating a first stream of OFDM symbols at a first base station, wherein each of the OFDM symbols includes a common set of subcarriers, wherein the first stream of OFDM symbols includes a plurality of zones, wherein each of the zones extends in a time dimension over more than one of the OFDM symbols and includes one or more subsets of the subcarriers, wherein the zones include a soft handoff zone, wherein a definition of the one or more subsets of subcarriers belonging to the soft handoff zone is shared by the first base station and one or more additional base stations that are participants in a soft handoff with respect to a first subscriber station;
wirelessly transmitting the first stream of OFDM symbols into space.
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Abstract
Soft handoff in an OFDMA system is disclosed. If the pilot signal strength for a base station exceeds the defined threshold, the base station is added to an active set list. Subcarriers in a plurality of orthogonal frequency division multiplexing (OFDM) symbols are divided and allocated into subchannels. The OFDM symbols are divided and multiplexed. A soft handoff zone with a first dimension of the subchannels and a second dimension of the divided and multiplexed OFDM symbols is defined. The soft handoff zone has subcarriers with a subchannel definition, for example, an identical permutation.
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Citations
20 Claims
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1. A method for facilitating soft handoffs in an orthogonal frequency division multiplexing access (OFDMA) system, the method comprising:
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generating a first stream of OFDM symbols at a first base station, wherein each of the OFDM symbols includes a common set of subcarriers, wherein the first stream of OFDM symbols includes a plurality of zones, wherein each of the zones extends in a time dimension over more than one of the OFDM symbols and includes one or more subsets of the subcarriers, wherein the zones include a soft handoff zone, wherein a definition of the one or more subsets of subcarriers belonging to the soft handoff zone is shared by the first base station and one or more additional base stations that are participants in a soft handoff with respect to a first subscriber station; wirelessly transmitting the first stream of OFDM symbols into space. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A base station in an orthogonal frequency division multiplexing access (OFDMA) system, the base station comprising:
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a processor; and memory storing program instructions, wherein the program instructions, when executed by the processor, cause the processor to; generate a first stream of OFDM symbols, wherein each of the OFDM symbols includes a common set of subcarriers, wherein the first stream of OFDM symbols includes a plurality of zones, wherein each of the zones extends in a time dimension over more than one of the OFDM symbols and includes one or more subsets of the subcarriers, wherein the zones include a soft handoff zone, wherein a definition of the one or more subsets of subcarriers belonging to the soft handoff zone is shared by the base station and one or more additional base stations that are participants in a soft handoff with respect to a first subscriber station; wirelessly transmit the first stream of OFDM symbols into space. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification