Abstract: Each of communication terminals MS#1 to MS#N spreads transmission data using an orthogonal spreading code that is specific to each of the communication terminals, performs OFDM modulation on the spread signal and thereby forms an OFCDM signal, and base station BS receives the OFCDM signal from each of communication terminals MS #1 to MS#N, performs OFDM demodulation on the received signal, despreads the OFDM demodulated signal using the orthogonal spreading code that is specific to each of the communication terminals and thereby obtains transmission data from each of communication terminals

Abstract: An error correction coding apparatus which improves the throughput of the whole system, while minimizing the increase of the circuit size and the amount of processing operation of the whole apparatus. In this apparatus, a data divider 132 divides transmission data into a plurality of blocks to generate n divided blocks. The n error correction coders out of N error correction coders 134 carry out an error correction coding on each of the n divided blocks in units of block, and outputs the divided blocks. A data concatenator 136 concatenates the n code blocks that have been error-correction-coded in units of block. A division/concatenation controller 138 controls at least one of data divider 132 and data concatenator 136 so that the division of the transmission data and the concatenation of the code blocks are carried out in units of bit.

Abstract: A disaster prediction system that provides a plurality of mobile communications apparatuses with a function for detecting abnormal signals that are effective in natural disaster prediction, manages location information for the mobile communications apparatuses and appropriately sets areas of natural disaster prediction, collects a plurality of abnormality detection signals from the mobile communications apparatuses, analyzes these signals per area of prediction, improves the accuracy of natural disaster occurrence prediction, and transmits natural disaster-related information to a plurality of mobile communications apparatuses present in the areas of prediction.

Abstract: A channel estimation section 112 estimates the states of channels used for pieces of mobile station apparatus (A) and (B), using signals demodulated by radio processing sections 110, 111. A best SIR calculation section 118 calculates coefficients to be used for signal transformation by inverse matrix calculation, using the above channel estimation values by the above channel estimation section 112. A signal transformation section 119 performs linear transformation of transmission signals to the above pieces of mobile station apparatus, using the above coefficients from the above best SIR calculation section 118. Radio processing sections 120, 121 modulates each transmission signal after the above linear transformation for transmission through antennas 108, 109, respectively.

Abstract: The fading correlation monitor 103 detects an angle spread of the communication terminal apparatus 200-1 and decides whether the angle spread has a larger or smaller relationship with a preset threshold value. When the estimated angle spread is smaller than the threshold value, the interference wave is suppressed by carrying out directive reception which is carried out by an AAA receiver 106 as well as performing directive transmission which is carried out in a transmitting circuit 122.While, when the estimated angle spread is larger than the predetermined value, the distortion of the signals due to the fading is compensated by carrying out diversity receiving which is carried out in a diversity receiver 107 as well as performing diversity transmission which is carried out in a diversity transmitter 123.On account of this, even when the fading correlation is small, it is possible to carry out a radio communication with a satisfactory communication quality.

Abstract: A modulation apparatus is disclosed that enables great improvements in signal transmission rate in a limited frequency band as compared with conventional modulation schemes. Modulation apparatus 100 has first and second frequency-increasing SSB modulators 110 and 120. The modulators 110 and 120 are configured to have respective carrier frequencies with a difference by a frequency corresponding to the reciprocal of the symbol rate (i.e. fundamental frequency of the input symbol). Adder 130 combines a LSB signal obtained from the SSB modulator 120 set for a higher carrier frequency, and a USB signal obtained from the SSB modulator 110 set for a lower carrier frequency to obtain a modulation signal.

Abstract: ej(2nn/N) calculating section 101 generates a bth chip C(a,b) of an ath spreading code based on C(a,b)=ej(2nn/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 communication system and scheduling method where, when data are transmitted from a plurality of transmit antennas to respective different mobile station apparatuses, all the mobile station apparatuses precisely receive data addressed thereto. A scheduler (104) performs scheduling that determines a data transmit order, depending on the numbers of receive antennas of the respective mobile station apparatuses, and notifies a transmit antennas assignment signal generator (124) of which transmit antenna is assigned which mobile station apparatus's sub-stream as the scheduling result. A number of receive antennas notifying signal decoder (122) decodes the number of receive antennas notifying signals and notifies the number of the receive antennas of each mobile station apparatus to the scheduler (104). The transmit antennas assignment signal generator (124) generates the transmit antennas assignment signal indicating which transmit antenna is assigned which mobile station apparatus's sub-stream.

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: A transmitting apparatus and method may inverse Fourier transform transmit data converted to parallel form to obtain a first signal. The band of a second signal is limited to a guard frequency band adjacent to the band of the first signal, and a signal comprising the first and second signals is transmitted.

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 spreader 112 of a base station apparatus 100 spreads transmission data at a low spreading factor at which a given signal quality can be little obtained after despreading at a mobile station apparatus 101, when an error detector 137 of the mobile station apparatus 101 detects an error in despread data of received data, a data retransmission request is performed to the base station apparatus 100 and despread data is held by a despreader/combiner 136. After that, the mobile station apparatus 101 repeats processing for combining the held data with the retransmitted data subjected to despreading until the time when an error-undetected state comes. This makes it possible to increase transmission efficiency, suppress transmission power extremely, and improve diversity performance to transmit data from a plurality of antennas.

Abstract: A likelihood calculating section 205 calculates a likelihood of a data portion signal and outputs a weighting coefficient according to the likelihood to a multiplier 206. The multiplier 206 multiplies a data channel estimation value output from a data channel estimating section 204 by the weighting coefficient output from the likelihood calculating section 205, whereby weighting the data channel estimation value according to likelihood of the data portion signal. A combining section 207 combines a PL channel estimation value with the data channel estimation value weighted according to the likelihood of data portion signal to obtain a final channel estimation value.

Abstract: A coding section 101 performs error detection coding of data for each predetermined error detection unit, and an M-ary modulation section 102 arranges data belonging to a plurality of error detection units in one transmission unit, and transmits that data. A first decoding section 114 decodes a received signal, and performs error detection on the decoding result for each error detection unit. A second demodulation section 115 modifies the likelihood of each bit based on the result of error detection in the first decoding section 114. By this means, it is possible to improve the error correction capability of a signal that has undergone M-ary modulation using high-precision likelihoods, and to improve transmission quality.

Abstract: A delay device 102 sends reception signals to a subtraction device 113 after delaying it by a predetermined time. Matched filters 103-1˜103-N perform despreading operation of the reception signals. RAKE-combining devices 104-1˜104-N perform RAKE-combining operation of the signals after the despreading operation. Discrimination devices 105-1˜105-N perform hard decision of the signals after the RAKE-combining operation. A decision value buffer 107 stores the signals after the hard decision. Likelihood calculation devices 106-1˜106-N calculate likelihood of all the symbols. A likelihood buffer 108 stores calculated likelihood. A controlling part 110 controls a switch 109. A ranking decision device 111 decides a ranking based on the likelihood. A re-spreading device 112 performs re-spreading operation of a symbol with the highest likelihood ranking. And a subtraction device 113 subtracts the re-spreading result from the delayed reception signals.

Abstract: Channel quality estimating section 104 estimates the channel quality from the reception signal quality and outputs the result to transmission method determining section 105 and control signal dividing section 108. Transmission method determining section 105 determines a transmission method of a signal transmitted to communication partner from channel conditions and outputs the result to switch 106, switch 107 and control signal dividing section 108. Control signal dividing section 108 divides the transmission method information into high-speed control signal which is transmitted periodically and low-speed control signal which is transmitted on demand rather than periodically. Moreover, control signal dividing section 108 determines the combinations of low-speed control signal and high-speed control signal outputted from a tendency of communication quality, and outputs the result to modulator 114.

Abstract: A server (191) transmits image information consisting of basic data and complementary data to a router (100) through the Internet (192). The router (100) allocates the basic data to a BS (110) of a cellular system (193) and the complementary data to an AP (120) of a wireless LAN system (194). The BS (110) transmits the basic data to a MS (150) and the AP (120) transmits the complementary data to the MS (150). When the MS (150) is located in the area of the cellular system (193), the MS always maintains a communication channel with the BS (110) and when the MS enters the area of the wireless LAN system (194), the MS also opens a channel with the AP (120) while maintaining the channel with the BS (110). This allows the user to continue seamless communication.

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: A communication terminal apparatus returns a unit of transmission with an error detected. A base station apparatus generates information indicating a position of an error within the unit of transmission while comparing a unit of transmission returned from the communication terminal apparatus with a corresponding unit of transmission stored in a buffer previous to transmission of the unit of transmission. The base station apparatus transmits the generated information to the communication terminal apparatus. The communication terminal apparatus corrects the error of the unit of transmission on the basis of the information.

Abstract: Radio section 103 multiplies modulated transmission signals A to D respectively by a carrier with a frequency of fA, fB, fC or fD, thereby performs the frequency conversion, and outputs the resultant signals to switch 104. Switch 104 switches between frequency conversion sections fA to fD and between antennas A to D to connect, and timing control section 105 outputs a timing control signal to switching control section 107 at time intervals for which timer 106 is preset. Switching control section 107 controls the switching of switch 104 according to switching patterns which are preset in switching pattern storage section 108 and which are each indicative of a connection relationship between antennas A to D and frequency conversion sections fA to fD.