Abstract: A base station apparatus which conducts a packet communication with a wireless communication terminal includes: a retransmission request detection unit which detects a retransmission request from the wireless communication terminal; a bandwidth assignment unit which assigns a communication bandwidth applied to the packet communication; a modulation class calculation portion, based on both bandwidth information regarding the bandwidth assigned by the bandwidth assignment unit and a data amount of packets corresponding to the retransmission request, calculates a modulation class applied to a retransmission in order to adjust a number of retransmitted packets to be the same as a number of previously transmitted packets; a modulation class determination unit which determines whether or not the modulation class is lower than a modulation class applied to a previous packet transmission; and a retransmission unit which retransmits packets corresponding to the retransmission request based on the determination result

Abstract: A wireless communication system which performs packet communication in a time division multiplexing communication format between wireless communication devices using either one or a plurality of communication channels includes: a resend request unit which detects that a received packet contains an error and requests a resend; a resend request detection unit which detects the request for a resend; a packet resend unit which resends the packet in accordance with the request for a resend detected by the resend request detection unit; and a channel allocation unit which allocates a different communication channel for the packet resend unit to resend the packet from the communication channel which was used for sending the packet in which the error detected by the resend request unit was contained.

Abstract: Present invention provides a communication method and a communication system that can provide more detailed communication control, larger transmission capacity, and more flexible resource distribution to users in comparison with a communication method using a conventional frame format. There are provided a downlink frame generator 14 that generates a downlink frame for a downlink period in which a cell station 10 communicates with at least one personal station of the plurality of personal stations 20 in a predetermined frame format, and an uplink frame generator 24 that generates an uplink frame for an uplink period in which at least one personal station of the plurality of personal stations communicates with the cell station 10 in a predetermined frame format, wherein the frame format of the downlink frame includes a MAP field that notifies, in the downlink period, each personal station of information indicating an available or unavailable subchannel for each personal station.

Abstract: A base station apparatus which conducts a packet communication with a wireless communication terminal includes: a retransmission request detection unit which detects a retransmission request from the wireless communication terminal; a bandwidth assignment unit which assigns a communication bandwidth applied to the packet communication; a modulation class calculation portion, based on both bandwidth information regarding the bandwidth assigned by the bandwidth assignment unit and a data amount of packets corresponding to the retransmission request, calculates a modulation class applied to a retransmission in order to adjust a number of retransmitted packets to be the same as a number of previously transmitted packets; a modulation class determination unit which determines whether or not the modulation class is lower than a modulation class applied to a previous packet transmission; and a retransmission unit which retransmits packets corresponding to the retransmission request based on the determination result

Abstract: There are provided an OFDMA communication system capable of reducing a time necessary for a handover without releasing a wireless communication with a base station as a handover source to search base stations, a base station and a mobile station used in the communication system, and a base station switching method. In an OFDMA communication system in which data communication is performed between a plurality of base stations 10 and a plurality of mobile stations, each base station 10 includes subchannel assignment setting unit 15-1 which sets assignment of subchannels including a first subchannel and a second subchannel for each of the mobile stations, the first subchannel including information indicating usable or unusable subchannels of the respective mobile stations and being assigned to the respective mobile stations, the second subchannel including actually-used data.

Abstract: In a communication system and a communication method using a TDD-OFDMA communication method, inter-carrier interference due to delay dispersion is prevented by suppressing the delay time within a guard interval.

Abstract: A multiservice is implemented by connecting one base station and one terminal via one wireless link. There is provided communication control means 2-1 that performs communication in compliance with an OFDMA scheme having traffic channels including first sub-channels for containing information showing enabled or disabled sub-channels and second sub-channels for storing data pertaining to services in correspondence with the first sub-channels, that allocates a plurality of first sub-channels to a plurality of services, respectively, and that connects one base station to one terminal via one wireless link, thereby establishing communication pertaining to the plurality of services.

Abstract: Provided is a wireless communication system for performing communication using a shared control channel that can be used in a predetermined period for each of a plurality of base stations and a plurality of traffic channels that can be adaptively allocated to each of a plurality of wireless communication terminals. The wireless communication terminal is provided with a channel requesting unit that requests the base station to allocate an individual control channel through the shared control channel and a communication control unit that performs control information communication by wirelessly connecting the individual control channel allocated from the base station. The base station is provided with a channel allocating unit that allocates one of the traffic channels as the individual control channel to be exclusively used for the wireless communication terminal when the request of individual control channel allocation is received from the wireless communication terminal through the shared control channel.

Abstract: A multiservice is implemented by connecting one base station and one terminal via one wireless link. There is provided communication control means 2-1 that performs communication in compliance with an OFDMA scheme having traffic channels including first sub-channels for containing information showing enabled or disabled sub-channels and second sub-channels for storing data pertaining to services in correspondence with the first sub-channels, that allocates a plurality of first sub-channels to a plurality of services, respectively, and that connects one base station to one terminal via one wireless link, thereby establishing communication pertaining to the plurality of services.

Abstract: Improvement in utilization efficiency of traffic channels and voice quality in an OFDMA scheme is accomplished. A base station communicating which mobile stations by an OFDMA scheme using subchannels includes: a channel assigning unit 109a which assigns subchannels for communication to the mobile stations; and a call type acquiring unit 109b which acquires a type of a call as a communication object, wherein the channel assigning unit 109a changes a subchannel assignment procedure for assigning the subchannels to the mobile stations according to the acquired type of the call.

Abstract: There is provided an OFDMA communication system capable of suppressing the communication resource reduction and reducing the processing load on a base station. The system includes a downlink frame generation unit (14) that generates a downlink frame for a downlink period for performing communication to at least one terminal (20) of a plurality of terminals from the base station (10), an uplink frame generation unit (24) that generates an uplink frame for an uplink period for performing communication to the base station (10) from at least one terminal (20) of the plurality of terminals, and a channel allocation unit that allocates, for one terminal of the plurality of terminals, one or more subchannels available in the one terminal, wherein the channel allocation unit allocates, among the subchannels, subchannels having a same time slot and a same frequency band in the downlink frame and in the uplink frame for a single terminal of the plurality of terminals.

Abstract: Each mobile station device (12) includes: a subchannel allocation refusal determining section (50), which determines a subchannel refused to be allocated from a base station device (10), based on a communication quality measured for each subchannel by a communication quality measuring section (44); an RMAP creating section (52), which creates refused channel information (RMAP information) indicating the subchannel determined to be refused to be allocated; and a transmitting section (54) which gives notice of the created RMAP information to the base station device (10).

Abstract: In a communication system of the OFDMA communication method, even when transmission data is decreased temporarily and then increased again while communication by a user terminal is in progress, the communication can be continued without lowering the communication throughput of the user terminal and the throughput corresponding to QoS can be provided to the user terminal. The OFDMA communication system for performing data communication using one or more subchannels between a base station (1) and a plurality of terminals includes a communication data amount acquisition unit that acquires a communication data amount and a channel allocation unit that allocates the subchannels according to the communication data amount. When the communication data amount has decreased, the channel allocation unit maintains allocation of at least one of the allocated subchannels.

Abstract: The present invention relates to a wireless communication system for TDMA communication with use of one or more communication channels among at least one of a plurality of cell stations and a wireless communication terminal. The wireless communication terminal includes a link-channel-allocation requesting unit that transmits a link-channel allocation request signal upon handover without specifying a destination cell station, using a handover control channel included in the communication channels which is used for transmitting control information concerning handover and has a unique channel number in the wireless communication system. The one of the cell stations includes a link-channel allocating unit that transmits, to the wireless communication terminal, a link-channel allocation signal including link-channel allocation information using the handover control channel upon receiving the link-channel allocation request signal.

Abstract: There is provided an OFDMA communication system capable of suppressing the communication resource reduction and reducing the processing load on a base station. The system includes a downlink frame generation unit (14) that generates a downlink frame for a downlink period for performing communication to at least one terminal (20) of a plurality of terminals from the base station (10), and an uplink frame generation unit (24) that generates an uplink frame for an uplink period for performing communication to the base station (10) from at least one terminal (20) of the plurality of terminals. The downlink frame and the uplink frame have symmetric configurations.

Abstract: In a communication system of the OFDMA communication method, even when transmission data is decreased temporarily and then increased again while communication by a user terminal is in progress, the communication can be continued without lowering the communication throughput of the user terminal and the throughput corresponding to QoS can be provided to the user terminal. The OFDMA communication system for performing data communication using one or more subchannels between a base station (1) and a plurality of terminals includes a communication data amount acquisition unit that acquires a communication data amount and a channel allocation unit that allocates the subchannels according to the communication data amount. When the communication data amount has decreased, the channel allocation unit maintains allocation of at least one of the allocated subchannels.

Abstract: There is provided an OFDMA communication system capable of suppressing the communication resource reduction and reducing the processing load on a base station. The system includes a downlink frame generation unit (14) that generates a downlink frame for a downlink period for performing communication to at least one terminal (20) of a plurality of terminals from the base station (10), an uplink frame generation unit (24) that generates an uplink frame for an uplink period for performing communication to the base station (10) from at least one terminal (20) of the plurality of terminals, and a channel allocation unit that allocates, for one terminal of the plurality of terminals, one or more subchannels available in the one terminal, wherein the channel allocation unit notifies information of the allocated one or more available subchannels to the one terminal only by the downlink frame.

Abstract: A base station device (10) performs communications with multiple mobile station devices (20) by the OFDMA scheme. The base station device (10) includes an intra-frame region specifying unit (16) configured to specify a region in a downlink frame to be specified by at least the sub-channel and a transmitter (13) configured to transmit MAP region information indicating the specified downlink intra-frame region. The intra-frame region specifying unit (16) specifies a region in a frame that is to contain communication data. The base station device (10) further includes a MAP generator (121) configured to generate MAP indicating the specified intra-frame region, and the transmitter (13) transmits a downlink frame containing the generated MAP in all or a part of the downlink intra-frame region specified by the MAP region information.

Abstract: Provided is a wireless communication system in which a plurality of channels are shared and one of the channels is adaptively allocated to a wireless communication terminal by a base station. The wireless communication terminal is provided with a channel requesting unit that requests the base station to allocate an individual control channel when a communication request is received from an upper control unit of its own terminal or the base station, and a state control unit that controls the state of its own terminal so that the state transits to an individual control channel connected state in which control information is transmitted/received by wirelessly connecting the individual control channel allocated from the base station. The base station is provided with a channel allocating unit that allocates one of a plurality of traffic channels as the individual control channel to be exclusively used for the wireless communication terminal in response to the request from the wireless communication terminal.

Abstract: A mobile station device (12) includes a retransmission request transmission timing identifying unit (40) which identifies, based on a timing of reception of a data frame transmitted from a base station device, a timing of transmission of a retransmission request of the data frame to the base station device. The base station device includes a retransmission data frame selecting unit which selects, based on a timing of reception of the retransmission request transmitted from the mobile station device (12), a data frame to be retransmitted from among a plurality of data frames transmitted to the mobile station device (12), and retransmits a data frame selected by the retransmission data frame selecting unit to the mobile station device (12).