Abstract:
An OFDM communication apparatus that can set an optimum repetition number to data to be transmitted, thereby improving the error rate characteristic and hence the communication quality. In this apparatus, a repetition number deciding part (153) decides, based on quality information outputted from a quality information extracting part (152), a required repetition number. A systematic bit repetition number deciding part (154) decides, based on the repetition number notified of by the repetition number deciding part (153), an optimum repetition number for the systematic bit. A parity bit repetition number deciding part (155) operates similarly. Repetition parts (103-1, 103-2) repeat the bits in accordance with instructions from the systematic bit repetition number deciding part (154) and from the parity bit repetition number deciding part (155).
Abstract:
A duplicating section 11 duplicates a bit sequence to be input, and a 16QAM section 121 modulates a bit sequence of a duplicating source to form a symbol, a 16QAM section 122 modulates the duplicated bit sequence to form a symbol, an S/P section 13 parallel converts the symbol sequence input in series, an S/P section 14 parallel converts the symbol sequence input in series, and an IFFT section 15 provides IFFT processing to the input symbol sequence. Since each of multiple same bits duplicated by the duplicating section 11 is included in a different symbol, each of the multiple same bits is allocated to each of multiple subcarriers each having a different frequency by IFFT processing. As a result, a multicarrier signal including the multiple same bits each having a different frequency is generated.
Abstract:
MS receives a downlink signal transmitted based on a guard interval determined using a delay profile with high accuracy generated based on a CDMA uplink signal, and performs Fourier Transform processing on a preamble portion of the downlink signal to demodulate. Transmission parameters (guard interval, subcarrier frequency interval and the number of subcarriers) contained in the preamble portion are extracted and output to Fourier Transform section 303. The section 303 performs Fourier Transform processing on a data portion based on the extracted transmission parameters. Demodulation section 304 demodulates signals subjected to the Fourier Transform processing to output as received data. It is thereby possible to generate the delay profile with high accuracy to determine the guard interval, and to ensure transmission quality while improving the spectral efficiency.
Abstract:
There is provided a mobile station device in a multi-hop system capable of realizing relay of communication of another station while suppressing increase of power consumption of the local station. In this device, at timing t1, a mobile station MS2 transmits data S2 destined to a base station BS1, to a mobile station MS1. The mobile station MS1 receives the data S2 and temporarily stores it in a buffer. The mobile station MS1 waits until timing t4 when the data S1 of the mobile station MS1 is to be transmitted. When this timing has come, the data S2 stored in the buffer is multiplexed with the data S1 of the mobile station MS1 and transmitted to the base station BS1.
Abstract:
A radio transmission apparatus capable of suppressing peak power without causing deterioration in throughput and degradation in transmission efficiency in multicarrier communication. In this apparatus, a coding section (11) codes transmission data, a modulation section (12) modulates the coded data to generate a symbol, an assigning section (13) assigns the symbol to one of a plurality of subcarriers constituting a multicarrier signal, a changing section (15) change the phase of each of the plurality of subcarriers within a range that does not cross a decision boundary for signal points on an IQ plane, and an IFFT section (16) generates a multicarrier signal by inverse fast Fourier transform.
Abstract:
Receiving a packet interleaved with an interleave pattern corresponding to the number of times of retransmission, reception apparatus (200) de-interleaves a pilot sequence contained in the packet with de-interleavers (205-1˜205-N). Correlators (206-1˜206-N) performs correlation calculation between the de-interleaved pilot sequence and a pilot pattern held in the reception apparatus. Maximum value detection section (207) detects the maximum correlation value among the correlation values to detect the number of times of retransmission. Decision section (209) controls combination circuit (213) and error detection section (217) based on the number of times of retransmission stored in storage section (208) and on the number of times of retransmission detected at maximum value detection section (207). This allows a decrease in throughput to be prevented from occurring even in a case where a reception side receives a packet which is different from one which is requested by the reception side.
Abstract:
In a communication system that combines HDR system and IS-2000 system, when mobile station 101 receives an interruption request from IS-2000 system while performing high-speed packet communication system under HDR system, BTS 105 modifies priority of MS 101 higher than when there is no interruption request and assigns communication resources accordingly. By thus adequately operating HDR system and IS-2000 system, it is possible to offer a wireless communication system that efficiently combines the services of both systems, as well as a base station apparatus and a communication terminal for use in the system.
Abstract:
A base station apparatus that limits the influx of speech data into a packet channel and that enables the service quality of the packet channel to be prevented from degrading. In this apparatus, a protocol detecting section (301) detects a protocol contained in an IP header of a packet. Based on the protocol, a packet type detecting section (302) detects a type of packet. Based on the type of packet, a delay addition control section (303) determines whether or not to add a delay. Specifically, when the packet is of VoIP, the delay addition control section (303) instructs a switching section (304) to output the packet to a delay adding section (103), and further instructs the delay adding section (103) to add a delay. Meanwhile, when the packet is an IP packet, the delay addition control section (303) instructs the switching section (304) to output the packet to a scheduler (104).
Abstract:
Respective threshold value judging units 108-1 through 108-n compare the likelihoods calculated by the corresponding likelihood calculators 106-1 through 106-n with threshold values stored in a threshold value buffer 109 in terms of size, and output signals, which show the corresponding likelihood in only a case where the likelihood is the threshold value or more, through a likelihood transmission bus 110. The rank decision unit 112 ranks the symbols for which the likelihood is an appointed threshold value or more, on the basis of the likelihoods stored in the likelihood buffer 111, whereby it is possible to relieve the traffic of a bus line and to suppress the amount of processing in a ranking process with respect to all non-demodulated symbols.
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.