Abstract: 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.

Abstract: A wireless station is used as one of a plurality of relay stations forming transmission paths, respectively, different from each other, in a wireless transmission system for transmitting a packet from a transmitting station to a receiving station through the plurality of relay stations. The wireless station includes a reception section for receiving a packet transmitted from the transmitting station, and receiving a packet which is transmitted, based on the packet transmitted from the transmitting station, from another relay station, and is transmitted before the one of the plurality of relay stations performs transmission, by using a transmission parameter for obtaining a path diversity effect in the wireless transmission system.

Abstract: 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.

Abstract: Interfering signals coming at random timings from different radio stations are identified. In order to attain this, a method for storing the characterizing quantity of an interfering signal included in a received signal includes calculating the characterizing quantity of the received signal, determining a probability that a desired signal is included in the received signal, determining that the received signal is an interfering signal when determining that there is no probability that the desired signal is included in the received signal, and storing the characterizing quantity of the received signal as an interfering signal characterizing quantity when it is determined at the received signal determination step that there is no probability that the desired signal is included in the received signal.

Abstract: A correlation unit (32) sequentially obtains correlation values between a baseband signal and a reference signal and outputs the obtained reference signal to a section division unit (33). The output of the correlation unit (32) is divided into symbol time periods by the section division unit (33). A section position detection unit (34) detects a largest correlation value in each of sections resulting from the division by the correlation unit (32) and outputs, to a synchronization judgment unit (35), first position information that indicates a relative position of each detected largest correlation value. The synchronization judgment unit (35) detects an arrival of a packet signal and estimates a symbol timing based on the first position information of the sections.

Abstract: A two-point modulator using a voltage control oscillator includes: a modulation section including a feedback circuit for performing feedback control of a signal outputted from the voltage control oscillator based on an inputted modulated signal, and a feedforward circuit for calibrating the modulated signal and outputting the calibrated modulated signal to the voltage control oscillator; a signal output section for, upon calibration processing, outputting a predetermined reference signal in place of the modulated signal, to the modulation section; and a gain correction section for, in a state where the feedback circuit is in an open loop state, calculating a frequency transition amount of the reference signal outputted from the voltage control oscillator, and correcting a gain used for calibration of the modulated signal performed by the feedforward circuit, based on the calculated frequency transition amount.

Abstract: An FLL circuit having a capability of configuring a desired loop bandwidth in a short period of time is provided. An FDC 17 generates a feedback of an output signal of a VCO 15. An error detector 11 detects an error of the output signal of the VCO 15. A voltage retainer 13 retains an output of a control voltage of the VCO 15. A reference signal generator 16 generates a reference signal. An adder 14 adds the reference signal to a control voltage outputted by the voltage retainer 13. A Kv calculator 18 calculates a gain Kv of the VCO 15 based on a degree of transition of an output frequency of the VCO 15. A loop bandwidth controller 19 adjusts, based on the gain Kv of the VCO 15, a gain of a loop filter 12 to an optimum value, and configures a desired loop bandwidth.

Abstract: An FLL circuit having a capability of configuring a desired loop bandwidth in a short period of time is provided. An FDC 17 generates a feedback of an output signal of a VCO 15. An error detector 11 detects an error of the output signal of the VCO 15. A voltage retainer 13 retains an output of a control voltage of the VCO 15. A reference signal generator 16 generates a reference signal. An adder 14 adds the reference signal to a control voltage outputted by the voltage retainer 13. A Kv calculator 18 calculates a gain Kv of the VCO 15 based on a degree of transition of an output frequency of the VCO 15. A loop bandwidth controller 19 adjusts, based on the gain Kv of the VCO 15, a gain of a loop filter 12 to an optimum value, and configures a desired loop bandwidth.

Abstract: A wireless transmission system capable of performing multi-station simultaneous transmission of data by wireless is provided. The wireless transmission system includes a plurality of wireless stations for transmitting and receiving data. Transmitter-side wireless stations, a multipath channel, and receiver-side wireless stations constitute a system for path diversity. At least one wireless station among the wireless stations determines, depending on a response packet with respective to a multi-station simultaneous transmission request packet transmitted by itself or other stations, a plurality of delay amounts from a reference timing during multi-station simultaneous transmission in the wireless transmission system, and a plurality of symbol waveforms that are a basis for a modulated waveform.

Abstract: In a wireless communication system using the contention method, collisions between transmission signals sent from terminals to a base station are avoided, and a communication area is flexibly formed while suppressing unnecessary radiation of the communication area.

Abstract: The noise amount information storage unit 161 stores noise amount information which indicates relationships between gain value of the variable gain amplification units 121 and 125 and the amount of noise included in BB signals output from the down converters 131 and 135. The AGC unit 140 controls the gain value of the variable gain amplification units 121 and 125 so that the power of BB signals output from the down converters 131 and 135 becomes constant. The noise amount estimation unit 162 estimates noise amount of noise corresponding to the controlled gain value of the variable gain amplification units 121 and 125 by referring to the noise amount information stored in the noise amount information storage unit 161. The weight generation unit 170 generates weight matrix based on results of estimations performed by the channel characteristic estimation unit 150 and the noise estimation unit 162.

Abstract: A wireless transmission system exerts a maximum path diversity effect even if the maximum number of effective branches is limited to a small number. A transmission timing control section determines a transmission start timing to be a timing obtained by delaying a reference timing by a predetermined delay amount. A modulation section modulates a signal by a modulation scheme such that an anti-multipath property is exerted when the signal is demodulated on a receiver side, and transmits the modulated signal at the transmission start timing. In a receiving station, a demodulation section demodulates the receive signal to obtain receive data.

Abstract: A wireless transmission system capable of performing a multi-station simultaneous transmission of data, that is, simultaneously transmitting data by wireless to a plurality of stations. The wireless transmission system includes a plurality of wireless stations for transmitting/receiving data and it constitutes a system for path diversity by use of a wireless station at the transmitting end, a multipath transmission path, and a wireless station at the receiving end. At least one of the plurality of wireless stations decides, in accordance with a response packet responsive to a multi-station simultaneous transmission request packet transmitted by the wireless station or other stations, a plurality of delay amounts relative to a reference timing during the multi-station simultaneous transmission in the wireless transmission system.

Abstract: An AGC unit 111 starts a gain control of the variable gain amplifying unit 102 when a bit saturation occurs in the digital baseband signal output from the A/D converting unit 104, and starts a gain control of the variable gain amplifying unit 102 when a detection of STS from the digital baseband signal output from the A/D converting unit 104 is started. The AGC unit 111 performs the gain control of the variable gain amplifying unit 102 once when the detection of STS is started, and performs the gain control of the variable gain amplifying unit 102 twice when the bit saturation occurs, namely a larger number of times than when the detection of STS is started.

Abstract: A wireless station capable of increasing the probability that a path diversity effect can be obtained in a case where a plurality of wireless stations transmit packets using a modulation/demodulation scheme with an anti-multipath property. A delay amount determining section (48) randomly selects a delay amount from among a plurality of candidate values. A transmission timing control section (47) determines a transmission start timing, at which to start the packet transmission, to be a timing obtained by delaying a reference timing by the delay amount selected by the delay amount determining section. At the transmission start timing, a modulation section (49) transmits the packet via an RF section (42) and an antenna (41). The difference between the candidate values is greater than or equal to a predetermined delay resolution, and the difference between a maximum candidate value and a minimum candidate value is less than or equal to a predetermined maximum delay.

Abstract: An FFT unit (170) separates a received symbol by Fourier conversion into a plurality of subcarriers, and a phase difference detection unit (193) detects a phase difference between 4 pilot carriers and data carriers adjacent to the pilot carriers (adjacent carriers) The decision unit (194) decides whether the phase differences between the pilot carriers and the adjacent carriers detected by the phase difference detection unit (193) fulfill a phase difference condition. Then, the decision unit (194) decides that the received symbol is an HTSIG if the number of phase differences that fulfill the phase difference condition is greater than or equal to a predetermined number, and decides that the received symbol is either a SIG or a DATA if the number of phase differences that fulfill the phase difference condition is less than the predetermined number.

Abstract: 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.

Abstract: A correlation unit (32) sequentially obtains correlation values between a baseband signal and a reference signal and outputs the obtained reference signal to a section division unit (33). The output of the correlation unit (32) is divided into symbol time periods by the section division unit (33). A section position detection unit (34) detects a largest correlation value in each of sections resulting from the division by the correlation unit (32) and outputs, to a synchronization judgment unit (35), first position information that indicates a relative position of each detected largest correlation value. The synchronization judgment unit (35) detects an arrival of a packet signal and estimates a symbol timing based on the first position information of the sections.

Abstract: 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.

Abstract: An object is to identify interfering signals coming at random timings from different radio stations. In order to attain this object, a method for storing the characterizing quantity of an interfering signal included in a received signal comprises a characterizing quantity calculation step of calculating the characterizing quantity of the received signal; a received signal determination step of determining a probability that a desired signal is included in the received signal, and determining that the received signal is an interfering signal when determining that there is no probability that the desired signal is included in the received signal; and an interfering signal characterizing quantity storage step of storing the characterizing quantity of the received signal as an interfering signal characterizing quantity when it is determined at the received signal determination step that there is no probability that the desired signal is included in the received signal.