Abstract: A modulation apparatus is disclosed that enables significant improvements in signal transmission rate in a limited frequency band as compared with conventional modulation schemes. The modulation apparatus has first and second frequency-increasing single side band (SSB) modulators. The modulators are configured to have respective carrier frequencies with a difference by a frequency corresponding to the symbol frequency (i.e. fundamental frequency of the input symbol). An adder combines a lower side band (LSB) signal obtained from the SSB modulator set for a higher carrier frequency, and an upper side band (USB) signal obtained from the SSB modulator set for a lower carrier frequency to obtain a modulation signal.

Abstract: A mobile terminal device for performing multi-carrier communication with a base station device can improve communication quality while reducing the data amount without lowering accuracy of feedback information.

Abstract: To narrow the dynamic range of multicarrier signals and prevent both the increment of cost and the degradation of power efficiency. A modulating part (101) modulates transport data. An S/P converting part (102) performs an S/P conversion of a modulated symbol and outputs the modulated symbols, the number of which is the same as the number of all subcarriers, to an IFFT part (103) in parallel. The IFFT part (103) assigns the modulated symbols to the subcarriers, the frequencies of which are orthogonal to each other, to perform an inverse fast Fourier transform. A P/S converting part (104) performs a P/S conversion of the signals of time domain. When the instantaneous amplitude level of an OFDM signal is lower than a predetermined threshold value, a pit clip part (105) replaces this amplitude level by the predetermined threshold value.

Abstract: A modulating device capable of generating an OFDM signal and having a drastically improved frequency use efficiency. The modulating device has modulators (6, 8 (11, 13, 106, 108, 111, 113)) for modulating a signal to be modulated and having a Nyquist roll-off frequency characteristic with a carrier frequency having a difference two times the Nyquist frequency and combiners (10(15, 110, 115)) for generating modulation output having a speed two times that of the signal to demodulated and the same Nyquist roll-off slope as the signal to be modulated by combining the outputs of the modulators (6, 8 (11, 13, 106, 108, 111, 113)). Thus a double speed wave can be superposed on the same frequency without varying the roll-off slope of the Nyquist characteristic, and therefore an OFDM signal (19) having a drastically improved frequency use efficiency is provided.

Abstract: ej(2n?/N) calculating section 101 generates a bth chip C(a,b) of an ath spreading code based on C(a,b)=ej(2n?/N) where e is a base of natural logarithm and N is a length of the spreading code (i.e. spreading code length). It is assumed in the above equation that n=a×b, a=0˜N?1, and b=0˜N?1. It is thereby possible to generate orthogonal spreading codes with arbitrary lengths.

Abstract: A radio receiving apparatus wherein the interference can be minimized and the power and bands can be effectively used in the process of receiving a signal comprising a combination of an impulse signal and an OFDM signal. In this apparatus, a transmission path equalizing part (205) performs a transmission path equalizing process of a signal comprising a combination of an OFDM signal and an impulse signal of UWB-IR system, and a signal separating part (208) uses a constant (C) to clip the amplitude level for a signal (Y1) demodulated as the OFDM signal, and substantially clips only the signal components of the impulse signal. Further, only when a signal (Y2) demodulated as the impulse signal exhibits an amplitude level greater than the constant (C), it is outputted, while most of the signal power of the combined OFDM signal is removed.

Abstract: A mobile terminal device for performing multi-carrier communication with a base station device can improve communication quality while reducing the data amount without lowering accuracy of feedback information.

Abstract: P/S conversion section 302 performs parallel/serial conversion of data sequences #1 through #4 input in parallel, in accordance with control by assignment control section 303, so that data to a higher-priority communication terminal is assigned to an upper bit in one symbol; M-ary modulation section 304 performs M-ary modulation on the data that has been subject to parallel/serial conversion; S/P conversion section 305 converts a symbol that has been subject to M-ary modulation to parallel form; multipliers 306-1 through 306-4 execute spreading processing on the symbols output in parallel; multiplexing section 309 multiplexes the symbol that has been subject to spreading processing with an assignment notification signal that has been subject to spreading processing; and radio transmitting section 310 transmits the multiplex signal.

Abstract: Of systematic bits (S) and parity bits (P1, P2) generated by coding (coding rate R=1/3) transmission bits, subcarriers to which parity bits are mapped are designated as candidates for transmission cancellation and subcarriers not to be transmitted are selected from among those candidates. When this selection is made, a selection pattern which corresponds to minimum peak power of an OFDM symbol is used based on values of parity bits and phase relationship between subcarriers.

Abstract: To narrow the dynamic range of multicarrier signals and prevent both the increment of cost and the degradation of power efficiency. A modulating part (101) modulates transport data. An S/P converting part (102) performs an S/P conversion of a modulated symbol and outputs the modulated symbols, the number of which is the same as the number of all subcarriers, to an IFFT part (103) in parallel. The IFFT part (103) assigns the modulated symbols to the subcarriers, the frequencies of which are orthogonal to each other, to perform an inverse fast Fourier transform. A P/S converting part (104) performs a P/S conversion of the signals of time domain. When the instantaneous amplitude level of an OFDM signal is lower than a predetermined threshold value, a pit clip part (105) replaces this amplitude level by the predetermined threshold value.

Abstract: A transmitting apparatus, a receiving apparatus and a wireless communication method for suppressing interference between codes, while further reducing the ratio of redundant components occupying a signal to improve the transmission efficiency. The transmitting apparatus (100) transmits a signal having a frame structure in which a plurality of symbols follow a pilot symbol to which a guard interval has been added. In the receiving apparatus (200) that receives that signal, a long FFT target section acquiring part (202) acquires, from the received OFDM signal, a long FFT target section that is a target section in which delay waves are to be removed by use of a pilot symbol. A long FFT part (203) performs a fast Fourier transformation of the long FFT target section to convert it to a frequency domain signal. A frequency equalizing part (204) performs a frequency equalization of the long FFT target section by use of an interpolation result of communication line estimation value.

Abstract: A radio receiving apparatus wherein the interference can be minimized and the power and bands can be effectively used in the process of receiving a signal comprising a combination of an impulse signal and an OFDM signal. In this apparatus, a transmission path equalizing part (205) performs a transmission path equalizing process of a signal comprising a combination of an OFDM signal and an impulse signal of UWB-IR system, and a signal separating part (208) uses a constant (C) to clip the amplitude level for a signal (Y1) demodulated as the OFDM signal, and substantially clips only the signal components of the impulse signal. Further, only when a signal (Y2) demodulated as the impulse signal exhibits an amplitude level greater than the constant (C), it is outputted, while most of the signal power of the combined OFDM signal is removed.

Abstract: P/S conversion section 302 performs parallel/serial conversion of data sequences #1 through #4 input in parallel, in accordance with control by assignment control section 303, so that data to a higher-priority communication terminal is assigned to an upper bit in one symbol; M-ary modulation section 304 performs M-ary modulation on the data that has been subject to parallel/serial conversion; S/P conversion section 305 converts a symbol that has been subject to M-ary modulation to parallel form; multipliers 306-1 through 306-4 execute spreading processing on the symbols output in parallel; multiplexing section 309 multiplexes the symbol that has been subject to spreading processing with an assignment notification signal that has been subject to spreading processing; and radio transmitting section 310 transmits the multiplex signal.

Abstract: A radio communication apparatus enabling reduction in peak-to-average power ratio without decreasing the transmission efficiency. In this apparatus, buffer section 103 temporarily stores input data prior to peak suppression. Peak detecting section 106 detects a peak with an amplitude level not less than a threshold. Peak cut section 107 reduces the detected peak to the threshold. Switching section 109 is switched so that the peak suppressed signal is output to FFT section 114 when the peak is detected, while the peak suppressed signal is subjected to transmission processing when the peak is not detected. Based on MCS information, signal recovering section 115 eliminates a signal assigned to a subcarrier set for MCS of a high level, and as a substitute, assigns the signal prior to peak suppression stored in buffer section 103. MCS setting section 116 selects MCS based on reception quality information of a communicating party.

Abstract: A method and apparatus for setting a guard interval in an OFDM communication. The method includes attaching a part of a first valid symbol to the first valid symbol as a guard interval and attaching a part of a second valid symbol requiring higher channel quality than the first valid symbol, to the second valid symbol as a guard interval, and providing the guard interval of the second valid symbol at a length greater than the guard interval of the first valid symbol.

Abstract: P/S conversion section 302 performs parallel/serial conversion of data sequences #1 through #4 input in parallel, in accordance with control by assignment control section 303, so that data to a higher-priority communication terminal is assigned to an upper bit in one symbol; M-ary modulation section 304 performs M-ary modulation on the data that has been subject to parallel/serial conversion; S/P conversion section 305 converts a symbol that has been subject to M-ary modulation to parallel form; multipliers 306-1 through 306-4 execute spreading processing on the symbols output in parallel; multiplexing section 309 multiplexes the symbol that has been subject to spreading processing with an assignment notification signal that has been subject to spreading processing; and radio transmitting section 310 transmits the multiplexed signal.

Abstract: In order to perform appropriate reception quality control on each mobile station in a multimedia broadcast/multicast service, a layered coding section 101 encodes input data by dividing the input data into two layers and obtains a first layer code string and a second layer code string. The first layer code string is input to a CRC code addition section 102 and a CRC code for an error inspection is added thereto at every predetermined block. On the other hand, the second layer code string is input to a CRC code addition section 103 and a CRC code for an error inspection is added thereto at every predetermined block. The first layer code string and the second layer code string with the CRC codes added are input to a layered modulation section 104 and the layered modulation section 104 modulates a plurality of code strings coded by being divided into a plurality of layers in such away that error rates differ hierarchically among the plurality of code strings and a radio section 105 sends the modulated symbol.

Abstract: A modulating device capable of generating an OFDM signal and having a drastically improved frequency use efficiency. The modulating device has modulators (6, 8 (11, 13, 106, 108, 111, 113)) for modulating a signal to be modulated and having a Nyquist roll-off frequency characteristic with a carrier frequency having a difference two times the Nyquist frequency and combiners (10(15, 110, 115)) for generating modulation output having a speed two times that of the signal to demodulated and the same Nyquist roll-off slope as the signal to be modulated by combining the outputs of the modulators (6, 8 (11, 13, 106, 108, 111, 113)). Thus a double speed wave can be superposed on the same frequency without varying the roll-off slope of the Nyquist characteristic, and therefore an OFDM signal (19) having a drastically improved frequency use efficiency is provided.

Abstract: An assignment section 101 determines communication resource assignment to communication terminals based on a transmission rate at which communication is possible for each subcarrier of each communication terminal, and instructs a buffer section 102 to output forward transmission data. In addition, the assignment section 101 instructs a frame creation section 103 to perform forward transmission data symbolization, and also outputs a signal indicating communication resource assignment to each communication terminal. The buffer section 102 holds forward transmission data, and outputs forward transmission data to the frame creation section 103 in accordance with instructions from the assignment section 101. The frame creation section 103 symbolizes a resource assignment signal and transmission data to create a frame, which it outputs to a spreading section 104.

Abstract: Noise generating section 106 generates noise data of a white Gaussian noise, and noise adding section 107 adds received data and the noise data. Channel estimating section 108 performs channel estimation using the added data output from noise adding section 107. At this point, when a level of a preceding signal is equal to or less than that of the noise data, channel estimating section 108 is not capable of detecting the preceding signal. Accordingly, in the case where a received level of a preceding signal is extremely lower than that of a delayed signal and a noise level is further lower than the received level of the preceding signal, it is possible to perform pre-equalization using the delayed signal as a desired signal, whereby it is possible to maintain the reception characteristic of a communication partner.