摘要:
In this signal detection device (100), a delaying unit (101) delays a first distributed signal or a second distributed signal distributed from a received signal for a period of time of T1 to form a first multiplication signal, and delays the one for a period of time of T2 (T2>T1) to form a second multiplication signal. An integrator (104) calculates a first correlation value by integrating the result of multiplying the first distributed signal and the first multiplication signal. An integrator (105) calculates a second correlation value by integrating the result of multiplying the second distributed signal and the second multiplication signal. An evaluation unit (108) evaluates whether the signal to be detected, which is a periodic signal with a period of T1 or a periodic signal with a period of T2, exists or not, on the basis of the first correlation value and the second correlation value.
摘要:
At a time T131, a wireless communication apparatus 11A determines to transmit a data packet, and then performs interference signal detection for a period TA. At a time T132, which precedes a time T133 at which the period TA has elapsed since the time T131, the wireless communication apparatus 11A detects a data packet d21 (an interference signal). At a time T134, at which a period TB has elapsed since the time T132 at which the interference signal has been detected, the wireless communication apparatus 11A starts transmitting a data packet d11 to a wireless communication apparatus 12A. At a time T136, the wireless communication apparatus 11A completes the transmission of the data packet d11.
摘要:
When communicating with a second wireless station, a first wireless station judges, based on link-related information received form the second wireless station and link-related information extracted from a signal transmitted by a fourth wireless station, whether a transmission link from the third wireless station to the fourth wireless station and a transmission link from the first wireless station to the second wireless station can be concurrently established without interference with each other. If judging affirmatively, the first wireless station transmits a signal to the second wireless station in synchronization with a signal transmitted by the third wireless station to the fourth wireless station. Preferably, when the first wireless station having a concurrent transmission control function communicates with the second wireless station having a interference reduction function, the first wireless station controls the interference reduction function of the second wireless station based on the link-related information received from the second wireless station and interference information, such that the transmission link from the third wireless station to the fourth wireless station and the transmission link from the first wireless station to the second wireless station can be established at the same time without interference with each other. If judging that the concurrent transmission is available, the first wireless station transmits a signal to the second wireless station according to a timing that overlaps transmission of a signal from the third wireless station to the fourth wireless station.
摘要:
Provided is a communication terminal device that reduces, in a network using a power line, the percentage of bands consumed for transmission of control packets in the bands consumed for all the communication, so as to ensure transmission of data intended to be transmitted. A PLC terminal F701 connected to the network of power line communication transmits, when having determined that the terminal does not receive from the network a beacon for a predetermined period of time, a beacon request packet to the network, using a modulation method having the lowest communication speed among the modulation methods that can be used in the network.
摘要:
In a transfer apparatus to which MIMO-OFDM is applied, a data transmission method and a data reception method are provided in which, even when there are frequency errors varying among transfer paths, the precision of estimation of an inverse propagation coefficient function can be improved, thereby making it possible to suppress a degradation in characteristics. Among symbols composed of a plurality of subcarriers orthognal to each other, the transfer apparatus uses, as a synchronization symbol, a symbol in which predetermined amplitudes and phases are assigned to a plurality of subcarriers spaced at predetermined frequency intervals. The synchronization symbol is divided into transmission antennas to generate a plurality of synchronization subsymbols, which are in turn simultaneously transmitted from a plurality of transmission antennas. A reception apparatus estimates a frequency error for each transfer path based on synchronization subsymbols included in signals received by a plurality of reception antennas, and based on the estimated frequency errors, corrects the received signals.
摘要:
A reception station 1b compares its BSSID with BSSID included in a signal that has arrived thereat. As BSSIDs included in signals transmitted by interfering stations 1c and 1d both match BSSID of the reception station 1b, the reception station 1b identifies each of the interfering stations 1c and 1d as a non-suppression target transmission source. As neither of BSSIDs included in signals transmitted by interfering stations 2a and 2b matches BSSID of the reception station 1b, the reception station 1b identifies each of the interfering stations 2a and 2b as a suppression target transmission source. The reception station 1b uses characteristic amounts of signals that are associated with the interfering stations (i.e., suppression target transmission sources) 2a and 2b and that have been measured in the past as characteristic amounts of interfering signals that are used to suppress the interfering signals from a received signal.
摘要:
A reception device according to the present invention receives a transmission frame including a synchronization symbol string, having a synchronization symbol repeated multiple times, inserted before a data symbol string. The synchronization symbol is obtained by synthesizing a plurality of sub band symbols which are mutually orthogonal and having different carrier frequencies. The carrier frequencies of the sub band symbols are located at an equal predetermined frequency interval. The synchronization symbol includes a repeated synchronization pattern. The reception device detects a rough carrier frequency error from a phase difference of a synchronization pattern correlation value to correct the frequency, and then detects a residual frequency error from an inter-symbol phase difference of each sub band to correct the frequency. The reception device detects a sampling clock frequency error from an inter-sub band phase difference to correct the frequency. Thus, the demodulation error of the data symbol is reduced.
摘要:
A communication apparatus is connected to a transmission channel capable of transmitting a plurality of kinds of data, each kind of data having different priority levels. The apparatus includes: an acquisition section which acquires each priority information of each kind of data on the transmission channel; and a transmission controller that, when transmitting data having a predetermined priority are transmitted from the communication apparatus, controls a time from a predetermined transmission reference time to a transmission end time of the transmitting data in accordance with the priority information.
摘要:
In the transmitter which carries out burst transmission using information data as a packet, if the status is divided into four modes, namely, burst stop mode, burst rising mode, burst continuous mode, and burst falling mode, a waveform shaping equipment designed to read out shaped waveform data for each mode from outputs of either of the two memory tables, the first memory table which holds waveform data for specific data patterns used in common in burst rising mode and burst falling mode and the second memory table which holds waveform data for all data patterns used in the burst continuous mode, or a waveform shaping equipment comprising the third memory table which holds waveform data corresponding to all the data patterns used in the burst rising mode and the fourth memory table which holds waveform data corresponding to all data patterns used in the burst falling mode and generating shaped waveform data by synthesizing the two outputs of the third and the fourth memory tables at the time of burst continuous mode.
摘要:
A data transmitting and receiving apparatus is disclosed. The receiving apparatus receives a spread spectrum signal prepared by modulating a carrier wave with data to produce a data modulated signal and multiplying the data modulated signal with a spreading signal which has a bandwidth greater than that of the data modulated signal. The receiving apparatus may include three bandpass filters for passing three different band portions of a full band of the spread spectrum signal and producing an intermediate signal, and a detector for detecting data from the intermediate signal and for producing a detector output. The apparatus may also include a reception state evaluation device for detecting the current reception state of the detector and for producing a poor reception signal, when the detector is in a poor reception state. The poor reception signal is used for changing from a current band to another band.