Preambles in OFDMA System
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Abstract
The present invention provides a preamble that is inserted into an OFDMA frame and has a common sequence for all the base stations participating in a transmission. The subscriber station performs fine synchronization using the common sequence on the common preamble, and the resulting peaks will provide the locations of candidate base stations. The base station specific search is then performed in the vicinities of those peaks by using base station specific pseudo-noise sequences. With this two stage cell search, the searching window is drastically reduced. The preamble is matched to known values by a respective receiver to decode the signals and permit multiple signals to be transferred from the transmitter to the receiver. The preamble may comprise two parts, Preamble-I and Preamble-2, which may be used in different systems, including multioutput, multi-input (MIMO) systems.
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Citations
96 Claims
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1-58. -58. (canceled)
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59. A base station in an orthogonal frequency division multiplexing access (OFDMA) system, the base station comprising:
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a) a training sequence configuring logic for generating a training sequence, said training sequence having a plurality of subcarriers; b) Inverse Fourier Transform (IFT) logic adapted to provide an IFT on each of said subcarriers to generate a plurality of OFDM symbols; and c) transmit circuitry configured for transmitting said plurality of OFDM signals for reception by a subscriber station, wherein said subscriber station is configured to perform synchronization using said training sequence. - View Dependent Claims (60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77)
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78. A method for operating a base station in an orthogonal frequency division multiplexing access (OFDMA) system, the method comprising:
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a) generating a training sequence, said training sequence having a plurality of subcarriers; b) providing an IFT on each of said subcarriers to generate a plurality of OFDM symbols; and c) transmitting said plurality of OFDM signals for reception by a subscriber station, wherein said subscriber station is configured to perform synchronization using said training sequence. - View Dependent Claims (79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96)
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Specification