| 摘要 |
Methods and apparatus are provided for improved efficiency in an extended multiple antenna communication system. A multiplier is employed on the number of points in the FFT that is greater than the multiplier on the frequency (bandwidth) of the legacy 802.11 a/g system. In one exemplary implementation, a 256 point FFT is employed in 40 MHz (with a 4N multiplier on the number of possible tones and a 2N multiplier on the frequency). While the efficiency for the OFDM symbol is improved, additional overhead is required in the preamble training (the length of the preamble is proportional to the number of tones in the FFT). Thus, a number of preamble constructs are provided that couple the improved efficiency with shorter preambles. In addition, an improved tone design provides additional efficiency gains.
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