Soft handoff in Ofdma system
First Claim
1. A method for facilitating soft handoffs in an orthogonal frequency division multiplexing access (OFDMA) system comprising the steps of:
- a) dividing subcarriers in a plurality of orthogonal frequency division multiplexing (OFDM) symbols;
b) allocating said divided subcarriers into subchannels;
c) dividing and multiplexing said plurality of OFDM symbols;
d) defining a soft handoff zone comprising a first dimension of said subchannels and a second dimension of said divided and multiplexed plurality of OFDM symbols;
said soft handoff zone having a first plurality of subcarriers, said first plurality of subcarriers having a subchannel definition; and
e) transmitting said first plurality of subcarriers in said soft handoff zone to a station.
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Accused Products
Abstract
The soft handoff in an OFDMA system. 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 have subcarriers with a subchannel definition, for example, an identical permutation.
178 Citations
74 Claims
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1. A method for facilitating soft handoffs in an orthogonal frequency division multiplexing access (OFDMA) system comprising the steps of:
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a) dividing subcarriers in a plurality of orthogonal frequency division multiplexing (OFDM) symbols; b) allocating said divided subcarriers into subchannels; c) dividing and multiplexing said plurality of OFDM symbols; d) defining a soft handoff zone comprising a first dimension of said subchannels and a second dimension of said divided and multiplexed plurality of OFDM symbols;
said soft handoff zone having a first plurality of subcarriers, said first plurality of subcarriers having a subchannel definition; ande) transmitting said first plurality of subcarriers in said soft handoff zone to a station. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. An orthogonal frequency division multiplexing access (OFDMA) system comprising:
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a) a base station controller adapted to schedule data for a subscriber station during a soft handoff mode; b) a plurality of base stations operatively associated with said base station controller, each base station participating in said soft handoff being adapted to receive at least a portion of scheduled data from said base station controller, and to transmit a first plurality of subcarriers to said subscriber station;
said first plurality of subcarriers being defined in a soft handoff zone comprising a first dimension of subchannels, said subchannels comprising said first plurality of subcarriers divided in a frequency domain; and
a second dimension of divided and multiplexed OFDM symbols comprising said first plurality of subcarriers;
said first plurality of subcarriers in said soft handoff zone having a subchannel definition. - View Dependent Claims (40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52)
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53. A base station in an orthogonal frequency division multiplexing access (OFDMA) system comprising:
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a) subchannel definition logic adapted to provide a subchannel definition to a first plurality of subcarriers; b) dividing and multiplexing encoding logic adapted to provide dividing-multiplexing coding for a plurality of orthogonal frequency division multiplexing (OFDM) symbols, said OFDM symbols comprising said plurality of subcarriers; c) Inverse Fourier Transform (IFT) logic adapted to provide an IFT on each of said first plurality of subcarriers to generate said plurality of OFDM symbols, said first plurality of subcarriers being defined in a soft handoff zone comprising a first dimension of subchannels, said subchannels comprising said first plurality of subcarriers; and
a second dimension of divided and multiplexed plurality of OFDM symbols;
said subcarriers in said soft handoff zone having a subchannel definition; andd) transmit circuitry transmitting said first plurality of subcarriers for reception by a subscriber station. - View Dependent Claims (54, 55, 56, 57, 58, 59, 60, 61, 62, 63)
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64. A subscriber station in an orthogonal frequency division multiplexing access (OFDMA) system comprising:
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a) receive circuitry adapted to receive and downconvert a plurality of OFDM signals, said plurality of OFDM symbols comprising a first plurality of subcarriers, said plurality of subcarriers being defined in a soft handoff zone comprising a first dimension of subchannels, said subchannels comprising said first plurality of subcarriers; and
a second dimension of divided and multiplexed OFDM symbols;
said first plurality of subcarriers in said soft handoff zone having a subchannel definition;b) Fourier Transform (FT) logic adapted to provide an FT on each of said first plurality of subcarriers to generate a plurality of division-multiplexing coded signals; and c) decoder logic adapted to provide division-multiplexing decoding on the plurality of divided-multiplexed coded signals to recover data from a base station. - View Dependent Claims (65, 66, 67, 68, 69, 70, 71, 72, 73, 74)
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Specification