Abstract: A frequency band is divided into N subchannels. Sub-channels are first allocated for a power line communication system having a higher priority, such as public communication or the like. Sub-channels for a power line communication system having a relatively low priority, such as in-home communication or the like, are allocated from free subchannels. In this case, the subchannels used by the power line communication system having the high priority are limited to a plurality of consecutive subchannels from an upper side or a lower side of the frequency band.

Abstract: A transmission schedule constructing apparatus constructing a transmission schedule for use in time division multiple access of stations on a power line communication network. The apparatus constructs the transmission schedule based on a cyclic change in a transmission quality of communication medium depending on an alternating current power source cycle on the power line and based on a parameter relating to transmission quality designated in the schedule allocation request.

Abstract: A frequency band is divided into N subchannels. Sub-channels are first allocated for a power line communication system having a higher priority, such as public communication or the like. Sub-channels for a power line communication system having a relatively low priority, such as in-home communication or the like, are allocated from free subchannels. In this case, the subchannels used by the power line communication system having the high priority are limited to a plurality of consecutive subchannels from an upper side or a lower side of the frequency band.

Abstract: There is provided a communication apparatus which, in an ad-hoc network, when receiving control packets from a plurality of terminals, can determine whether or not there is a collision among the control packets, and, based on the determination, can be prevented from continuing to be out of the network due to a collision among the control packets transmitted from the plurality of terminals. In the communication terminal, a communication section receives a control packet which periodically comes up on a communication path.

Abstract: A communications device 100, which performs data communication, includes an AC cycle sensor 30 which is connected to a power line 106 supplied with an a.c. voltage and generates a synchronous signal SS at timing of an a.c. voltage waveform AC of the power line 106; a data communicator 10 for performing data communication; and a communications controller 20 which performs communication of a control signal including information showing at least one of a communications device and a communications standard and controls the data communicator 101. When the a.c. voltage supplied to the power line 106 is an N-phase and when the cycle of the a.c. voltage waveform is T, data communication to be performed in a communication period subsequent to the period is controlled on the basis of the control signal included in the period of T/2M on condition that M is a natural multiple of N.

Abstract: A communications device 100, which performs data communication, includes an AC cycle sensor 30 which is connected to a power line 106 supplied with an a.c. voltage and generates a synchronous signal SS at timing of an a.c. voltage waveform AC of the power line 106; a data communicator 10 for performing data communication; and a communications controller 20 which performs communication of a control signal including information showing at least one of a communications device and a communications standard and controls the data communicator 101. When the a.c. voltage supplied to the power line 106 is an N-phase and when the cycle of the a.c. voltage waveform is T, data communication to be performed in a communication period subsequent to the period is controlled on the basis of the control signal included in the period of T/2M on condition that M is a natural multiple of N.

Abstract: In-home communication systems 110 and 130 and an access communication system 120 that are capable of co-existing. The communication systems 110 and 130 and the access communication system 120 are able to co-exist by utilizing TDM that is in synchronization with a power cycle. Further, communication system that needs to secure AV-QoS assigns transmission timing to a slave station within itself by synchronizing a beacon cycle with a cycle of a power line.

Abstract: Provides a terminal for performing multiple access transmission suitable to a transmission path having varied characteristics. The terminal (100) includes a transmission/reception section (201), a control unit (204), a transfer management section (206), and an external interface section (203). The terminal (100) refers to an IGMP (MLD) message received by the transmission/reception section (201) to classify a transmitter host and a relay device of this message based on the characteristic of the transmission path, and performs a multiple access transmission of a multicast packet in a form suitable to the characteristic of the respective transmission path.

Abstract: A communication system includes a synchronizing signal generator that generates a synchronizing signal based on a timing of an alternating waveform in a power line, a data communicating circuit that performs the data communication, and a communication controller that controls to acquire a transmitting right utilizing a timing of the synchronizing signal and to control the communication circuit in accordance with whether or not the communication apparatus acquires the transmitting right.

Abstract: Transmitter 2 includes inverse multicarrier transformer 23 and D/A converter 24. Inverse multicarrier transformer 23 generates a notch by masking a carrier at a frequency location predetermined in accordance with a communication method of the transmitter. D/A converter 24 performs a D/A conversion on a transmission signal containing the notch and transmits the signal to a transmission line. Receiver 1 includes power measurement unit 171, comparator 172 and coexistence signal determination unit 173. Power measurement unit 171 measures a power value of a signal input from the transmission line. Comparator 172 determines whether or not the notch exits by comparing the measured power value with a threshold. Coexistence method determination unit 173 determines the type of coexistence method, based on the location of the detected notch.

Abstract: A communication system includes a synchronizing signal generator that generates a synchronizing signal based on a timing of an alternating waveform in a power line, a data communicating circuit that performs the data communication, and a communication controller that controls to acquire a transmitting right utilizing a timing of the synchronizing signal and to control the communication circuit in accordance with whether or not the communication apparatus acquires the transmitting right.

Abstract: When operating as a control terminal and recognizing interference from another logical network, a terminal apparatus determines whether or not a logical network to be controlled is unified with the other logical network. When unification is determined, the terminal apparatus determines whether a control terminal of a logical network newly created by unification is the terminal apparatus or a control terminal of the other logical network.

Abstract: A transmission schedule constructing apparatus capable of constructing a transmission schedule for use in time division multiple access of stations on a power line communication network to a power line which is a communication medium, in which the transmission schedule is constructed based on a cyclic change in a transmission quality of communication medium depending on an alternating current power source cycle on the power line and a parameter relating to transmission quality designated in the schedule allocation request.

Abstract: Provided is a communication apparatus which prevents, when two or more communication systems share a single communication medium in a time-division manner, an occurrence of situation where only a particular communication system suffers an influence of noise synchronizing with an AC power supply cycle or a half cycle thereof. When the communication systems share a single communication medium 121 in a time-division manner, a communication control section 209 determines a coexistence communication period, which is cyclically allocated to the communication systems, to be N×M+A (N: arbitrary integer, M: half cycle of an AC power supply cycle, A: arbitrary offset value which is not an integral multiple of the half cycle of the AC power supply cycle). A synchronization signal transmission/reception section 212 transmits and receives a synchronization signal to and from a communication apparatus belonging to another communication system so as to synchronize with the communication apparatus.

Abstract: A communication apparatus, which is capable of allowing a plurality of communication systems respectively having different types of communication modes to coexist with one another on a single communication medium, satisfying Qos requirements with the use of only a simple configuration thereof, and minutely setting an exclusive use rate of a medium, is provided. A coexistence signal cycle T 209 is divided into M time periods by a communication slot unit 207 which is constituted of N communication slots. At least one communication slot in the communication slot unit 207 is defined as a “D-Slot” which can obtain a communication right M/X times during the coexistence signal cycle T 209, and remaining communication slots other than the D-Slot in the communication slot unit 207 is defined as “S-Slots” which can obtain the communication right M times during the coexistence signal cycle T 209.

Abstract: A communication system includes a synchronizing signal generator that generates a synchronizing signal based on a timing of an alternating waveform in a power line, a data communicating circuit that performs the data communication, and a communication controller that controls to acquire a transmitting right utilizing a timing of the synchronizing signal and to control the communication circuit in accordance with whether or not the communication apparatus acquires the transmitting right.

Abstract: A terminal of the present invention comprises a control frame detection portion of detecting a control frame issued from a control station, a control frame memory portion of storing control information contained in the control frame, a substitute frame issuance determination portion of determining to issue a substitute frame when the control frame is not detected until a predetermined first time period is elapsed, and a substitute frame issuance portion of creating a frame which is the same as or equivalent to the control frame, as the substitute frame, based on the control information stored in the control frame memory portion when the substitute frame issuance determination portion determine to issue the substitute frame, and issuing the created substitute frame.

Abstract: A communications device 100, which performs data communication, includes an AC cycle sensor 30 which is connected to a power line 106 supplied with an a.c. voltage and generates a synchronous signal SS at timing of an a.c. voltage waveform AC of the power line 106; a data communicator 10 for performing data communication; and a communications controller 20 which performs communication of a control signal including information showing at least one of a communications device and a communications standard and controls the data communicator 101. When the a.c. voltage supplied to the power line 106 is an N-phase and when the cycle of the a.c. voltage waveform is T, data communication to be performed in a communication period subsequent to the period is controlled on the basis of the control signal included in the period of T/2M on condition that M is a natural multiple of N.

Abstract: The present invention provides a terminal apparatus connectable to a communication network capable of comprising a plurality of different communication systems.

Abstract: A communication system includes a synchronizing signal generator that generates a synchronizing signal based on a timing of an alternating waveform in a power line, a data communicating circuit that performs the data communication, and a communication controller that controls to acquire a transmitting right utilizing a timing of the synchronizing signal and to control the communication circuit in accordance with whether or not the communication apparatus acquires the transmitting right.