Patent ID: 7443827

Claim:
A mobile communication system, which employs multicarrier code division multiple access, comprising a transmitting apparatus and a receiving apparatus, the transmitting apparatus having a slot generating unit that (1) generates, for each subcarrier group unit, a slot consisting of (a) a common pilot portion that is not used by a receiving apparatus to estimate a signal to interference ratio, (b) a known series portion, different from the common pilot portion, which the receiving apparatus uses to estimate the signal-to-interference ratio for each subcarrier group, and (c) a data portion, by using transmission data converted for each subcarrier group, (2) copies each slot by a predetermined number of subcarriers, and (3) outputs the slots; a modulating unit that modulates the signal copied for each subcarrier unit within the subcarrier group; a spread spectrum unit that individually carries out frequency spreading to a subcarrier signal within the modulated subcarrier group; a transmission power control unit that controls transmission power of the subcarrier signal after the spreading, for each subcarrier group; a multiplexing unit that multiplexes the subcarrier signal after the transmission power control, for each subcarrier group; and a transmitting unit that generates a predetermined signal by carrying out an inverse Fourier transformation processing, a guard interval setting processing, and a frequency conversion processing to the multiplexed subcarrier signal, and transmits the signal generated to a transmission line, and the receiving apparatus having a receiving unit that receives a signal on a transmission line, converts the signal received into a baseband signal, and carries out a Fourier transformation processing to the baseband signal; a common pilot extracting unit that extracts a common pilot portion included in each of the Fourier-transformed subcarrier signals; a channel estimating unit that calculates a channel estimate value for each subcarrier, by using the common pilot portion; a delay unit that delays each Fourier-transformed subcarrier signal by a time required to carry out the extraction processing and the channel estimate processing; a fading compensating unit that carries out a fading compensation to each of the delayed subcarrier signals, by using each of the channel estimate values; an inverse spread spectrum unit that inverse spreads a frequency of each of the fading-compensated subcarrier signals; an SIR estimating unit that estimates, for each subcarrier group signal, a signal to interference ratio by using the known series portion included in each subcarrier group signal after the inverse spreading, wherein the SIR estimating unit includes a subcarrier group averaging unit that averages the estimated signal-to-interference ratios corresponding to each subcarrier group and a known series extracting unit that extracts the known series portion from each subcarrier group signal; and a demodulating unit that demodulates the subcarrier group signal after the inverse spreading.