Patent ID: 8385480
Filing Date: 2013-02-26
Classification: H04L

Abstract:
1. A receiving apparatus comprising: first correlation value computation means for receiving an orthogonal frequency division multiplexing signal based on a predetermined standard for transmitting data in unit of a frame arranged, at a beginning of said frame, with a preamble signal having a correlation between a first section and a second section that are parts of an entire signal, thereby computing a first correlation value which is a correlation value of signals in two sections separated from each other by a time equal to a time interval between said first section and said second section; operation means for performing Fourier transform processing on said preamble signal including the signals of the two sections with said first correlation value equal to or higher than a threshold value obtained, thereby generating said orthogonal frequency division multiplexing signal of frequency domain; second correlation value computation means for computing a second correlation value which is a correlation value between a sequence of subcarriers for use in data transmission among subcarriers of said orthogonal frequency division multiplexing signal of frequency domain and a known sequence; decoding means for computing third correlation values, each of said third correlation values being a correlation value between data transmitted by subcarriers of a sequence with said second correlation value with said known sequence equal to or higher than a threshold value and a plurality of known items of data having a same number of bits as a bit train indicative of a transmission parameter for use in demodulation of a signal subsequent to said preamble signal, thereby decoding known data having a maximum value of said third correlation values as said transmission parameter; and determination means for determining whether said maximum value of said plurality of third correlation values computed by said decoding means is less than a predetermined threshold value and, if said maximum value is found to be less than said predetermined threshold value, outputting a signal indicative that said orthogonal frequency division multiplexing signal based on said predetermined standard is not being transmitted on a channel being received.