Abstract: A transmission control section 101 temporarily stores a transmission signal, outputs the stored transmission signal to a coding section 102 and outputs transmission timing information to a counter section 107. A preamble insertion section 104 inserts AGC preambles corresponding to the number set by a preamble number control section 110 into the transmission signal. The preamble number control section 110 compares a transmission time interval input from a subtraction section 109 with a threshold, decides to insert ten AGC preambles into the transmission signal when the transmission time interval is equal to or greater than the threshold and decides to insert five AGC preambles into the transmission signal when the transmission time interval is smaller than the threshold. By so doing, it is possible to make the transmission efficiency compatible with the error rate characteristic.

Abstract: An OFDM communication apparatus and OFDM communication method that both improve information signal transmission efficiency and improve demodulated signal error rate characteristics in an OFDM method to which multicasting is applied. An OFDM communication apparatus according to the present invention comprises a receiving section that receives an OFDM signal transmitted to a plurality of OFDM communication apparatuses, a detecting section that detects whether or not there is an error in a received OFDM signal, a generating section that generates a retransmission request OFDM signal by superimposing a retransmission request signal on a previously specified subcarrier when there is an error in a received OFDM signal, and a transmitting section that transmits a generated retransmission request OFDM signal at previously set timing common to all the above-mentioned plurality of OFDM communication apparatuses.

Abstract: An OFDM-CDMA transmission apparatus may include a first spreader that carries out spreading processing on a plurality of transmission signals using different spreading codes, respectively. A second spreader carries out spreading processing on at least one known signal using a spreading code different from the spreading codes employed by the first spreader. A frequency division multiplexer breaks down the transmission signals spread by the first spreader and the known signal spread by the second spreader into individual chips and subjects these chips to frequency division multiplexing, thereby assigning one chip data signal string per subcarrier. The frequency division multiplexer operates such that information from each of the plurality of transmission signals and the known signal is multiplexed into every chip assigned to a different subcarrier. After the chips are assigned to the subcarriers, they are transmitted by a transmitter.

Abstract: Modulation section 201 performs modulation processing on transmission data. Mapping control section 202 controls mapping of the baseband signal onto the subcarriers so that the important information conventionally transmitted by one subcarrier is transmitted by two subcarriers and one of the two subcarriers should be the subcarrier with a carrier frequency signal of frequency 0 which was conventionally not used. IFFT section 203 performs IFFT processing on the modulated transmission data. Transmission section 204 performs transmission processing on the IFFT-processed transmission data and transmits the processed transmission data from antenna 205.

Abstract: In a modulation method such as 8 PSK or a 16 PSK in which a sender device expresses a symbol by using three or more bits, important information is arranged at least at only one of the first and second bits, a receiver device extracts the important information from at least one of the first and second bits of the received signal, and thereby communication control is carried out based on the important information.

Abstract: Modulation section 201 performs modulation processing on transmission data. Mapping control section 202 controls mapping of the baseband signal onto the subcarriers so that the important information conventionally transmitted by one subcarrier is transmitted by two subcarriers and one of the two subcarriers should be the subcarrier with a carrier frequency signal of frequency 0 which was conventionally not used. IFFT section 203 performs IFFT processing on the modulated transmission data. Transmission section 204 performs transmission processing on the IFFT-processed transmission data and transmits the processed transmission data from antenna 205.

Abstract: It is an object of the invention to provide a communication apparatus that can perform gain control without deteriorating an S/N ratio of signals after diversity processing. A communication apparatus according to the invention includes: a comparison unit (11) that compares gain set values calculated and outputted by AGC control units (10a) and (10b) of respective branches; and conversion units (1004a) and (1004b) that generate gain adjustment signals corresponding to the respective branches from the gain set values obtained by the comparison unit (11). The communication apparatus performs gain control for variable gain amplifiers (5a) and (5b) of the respective branches according to the gain adjustment signals from the conversion units (1004a) and (1004b).

Abstract: A coding section 101 turbo-codes transmit data and outputs parity bit data, and systematic bit data for which good quality is required. A modulation section 102 modulates the parity bit data and systematic bit data. A subcarrier allocation section 103 rearranges the transmit data so that systematic bit data is allocated to subcarriers in the vicinity of the center frequency and parity bit data is allocated to subcarriers in the vicinity of both ends. An OFDM section 104 performs orthogonal frequency division multiplexing of the transmit data, and allocates parity bit data and systematic bit data to respective subcarriers. By this means, it is possible to improve significantly the error rate characteristics of transmit data for which good quality is required, and prevent degradation of the quality of transmit data for which good quality is required.

Abstract: In a modulation method such as 8PSK or a 16PSK in which a sender device expresses a symbol by using three or more bits, important information is arranged at least at only one of the first and second bits, a receiver device extracts the important information from at least one of the first and second bits of the received signal, and thereby communication control is carried out based on the important information.

Abstract: Synchronization symbol insertion section 102 inserts a synchronization symbol into a signal digital-modulated by modulation section 101. 0 symbol insertion section 103 inserts a 0 symbol into the signal with the synchronization symbol inserted. The signal with the synchronization symbol and 0 symbol inserted in this way is sent to IFFT section 104 to be subjected to an IFFT calculation. Then, guard interval insertion section 105 inserts a guard interval into the IFFT-transformed signal waveform. Then, the signal with the guard interval inserted in this way is D/A-converted by D/A converter 106. The D/A-converted signal is subjected to normal radio transmission processing and then transmitted.

Abstract: A communication system enabling significant reduction in delay in handover between MAPs without increasing the number of MAPs to install. In the communication system, MAP(101) issues a Router Advertisement to AR(111) to AR(118). Particularly, MAP(101) assigns a plurality of Router Advertisements of a source of care-of address (RCOA) to register with HA to AR(118) of a cell on either side of a boundary of areas for each MAP. MN(107) receives a Router Advertisement transmitted from AR that is a communicating party among AR(119) to AR(126), and using the Router Advertisement, generates care-of addresses, RCOA and LCOA. AR(111) to AR(118) transmit the Router Advertisement RA generated by MAP(101) to MN in communication. Further, AR(111) to AR(118) transmit the care-or-addresses, RCOA and LCOA, issued from MN(107) to MAP(101).

Abstract: A receiving section (102) performs a wireless receiving processing over a signal that is received through a receiving antenna (101), and output thereof to a propagation path compensation section (103) and an interference compensation section (104). The propagation path compensation section (103) conducts a propagation path compensation for the received signal, based on the result of the propagation path estimation. The interference compensation section (104) performs a propagation path estimation, and output this results to a controller section (105), and also performs a MIMO separation processing and output the separated received signals to a selecting section (106). The selecting section (106) selects one of the signals output from the propagation path compensation section (103) and the interference compensation section (104) under the control of the controller section (105) and output thereof.

Abstract: A control section 101 outputs retransmission information as to whether or not a transmit signal is a retransmission signal, and if a retransmission signal, which (first, second, etc.) retransmission this is, to a selection section 107. An IFFT section 103 performs orthogonal frequency division multiplexing processing of the transmit signal. A GI insertion section 104 inserts a guard interval in the transmit signal. A GI insertion section 105 inserts in the transmit signal a guard interval longer than the guard interval inserted by GI insertion section 104. A GI insertion section 106 inserts in the transmit signal a guard interval longer than the guard intervals inserted by GI insertion section 104 and GI insertion section 105. Based on the retransmission information input from control section 101, selection section 107 selects a transmit signal in which a longer guard interval has been inserted as the number of retransmissions increases.

Abstract: An S/P converting section (101) converts input transmission signals A1, A2, B1, B2, . . . , K1, K2 to parallelized data, separated in individual transmission lines. Spreading sections (102, 103) spread the respective data under control of a spread control section (107). Adding sections (104-1, 104-2) multiplex spread data. Transmitting sections (105-1, 105-2) provide radio transmission processing to the multiplexed signals, and transmit the data via antennas (106-1, 106-2) by radio. The spread control section (107) controls the spreading methods in the spreading sections (102, 103) based on channel quality. This makes it possible to improve error rate characteristics of the received signal and as maintain spectrum efficiency when varying data is transmitted from multiple antennas.

Abstract: A control section (110) recognizes the type of data included in a transmission signal and outputs a control signal (C1) to an S/P conversion section (101) and a spreading control section (107). The S/P conversion section (101) apportions a specific type of data output from the control section (110) to different transmission systems. Spreading sections (102, 103) carry out spreading processing on the specific type of data output from the S/P conversion section (101) with different spreading codes assigned thereto under the control of the spreading control section (107). The data output from the spreading sections (102, 103) is transmitted by radio through addition sections (104-1, 104-2), transmission sections (105-1, 105-2) and antennas (106-1, 106-2). In this way, it is possible to improve the reception performance on the receiving side for specific data while maintaining the transmission efficiency of an MIMO communication system.

Abstract: A turbo encoding section 102 turbo-encodes transmission data, outputs systematic bit data to a first modulation section 103a and outputs parity bit data to a second modulation section 104. The first modulation section 103a always QPSK-modulates systematic bit data. The second modulation section 103b adaptively modulates parity bit data. The control section 101 outputs a control signal for carrying out 16 QAM modulation to the second modulation section 103b when the RSSI value is equal to or higher than a threshold and outputs a control signal for carrying out QPSK modulation to the second modulation section 103b when the RSSI signal value is less than the threshold. In this way, it is possible to further make the error rate characteristic compatible with the transmission efficiency.

Abstract: A transmission control section 101 temporarily stores a transmission signal, outputs the stored transmission signal to a coding section 102 and outputs transmission timing information to a counter section 107. A preamble insertion section 104 inserts AGC preambles corresponding to the number set by a preamble number control section 110 into the transmission signal. The preamble number control section 110 compares a transmission time interval input from a subtraction section 109 with a threshold, decides to insert ten AGC preambles into the transmission signal when the transmission time interval is equal to or greater than the threshold and decides to insert five AGC preambles into the transmission signal when the transmission time interval is smaller than the threshold. By so doing, it is possible to make the transmission efficiency compatible with the error rate characteristic.

Abstract: The OFDM communication apparatus according to the present invention includes a plurality of interleave sections capable of executing mutually different interleave processing on a transmission signal, a selection section for selecting the interleave section to execute interleave processing on the transmission signal from among the plurality of interleave sections and an OFDM section for performing OFDM processing on the transmission signal interleaved by the selected interleave section.

Abstract: A transmission-reception apparatus does not configure ARQ control information from only sequence number, but the transmission-reception apparatus configures the ARQ control information such that the ARQ control information is comprised of one sequence number containing first occurrence of a corresponding packet's error, and bit information representing existence of retransmission requirements about sequence numbers followed on the heels of such the one sequence number.

Abstract: Synchronization symbol insertion section 102: inserts a synchronization symbol into a signal digital-modulated by modulation section 101. 0 symbol insertion section 103 inserts a 0 symbol into the signal with the synchronization symbol inserted. The signal with the synchronization symbol and 0 symbol inserted in this way is sent to IFFT section 104 to be subjected to an IFFT calculation. Then, guard interval insertion section 105 inserts a guard interval into the IFFT transformed signal waveform. Then, the signal with the guard interval inserted in this way is D/A-converted by D/A converter 106. The D/A-converted signal is subjected to normal radio transmission processing and then transmitted.