Adaptation of frequency of occurence of transmission of a reference signal based on the channel quality in an OFDM system

摘要

An orthogonal frequency division multiplexed signal transmitting apparatus executes a time-division multiplexing process that inserts a reference signal at a predetermined interval based on reference signal position information into an information signal to be transmitted. The transmitting apparatus generates an orthogonal frequency division multiplexed signal by digital-modulating the time-division multiplexed signal to radiate into a spatial transmission line. An orthogonal frequency division multiplexed signal receiving apparatus receives the signal from the transmitting apparatus to get the reference signal by demodulating the signal. The receiving apparatus analyzes the resultant reference signal as positions of signal points on a two-dimensional plane that is represented by an in-phase axis and a quadrature axis, then decides a time interval, at which the reference signal is transmitted, based on the analyzed result, and then supplies the time interval information to the transmitting apparatus. The transmitting apparatus changes the current time interval based on the information of the time interval, at which the reference signal is transmitted, received from the receiving apparatus. <IMAGE>