摘要:
A wireless network system including a first terminal for sending a request-to-send signal including information on a medium use period to a second terminal before sending data, receiving a clear-to-send signal from the second terminal, and sending data to the second terminal during the medium use period; the second terminal for receiving the request-to-send signal and sending the clear-to-send signal; a third terminal for receiving the request-to-send signal and transmitting data to a fourth terminal during the medium use period; and the fourth terminal. Thus, it is possible to prevent occurrence of a problem that when it is judged that the wireless channel is being used, transmission of the station is suppressed.
摘要:
A spatial filtering adaptable for an interference wave that appears unsteadily can be implemented and also an interference canceling ability can be increased even in a condition that the interference wave does not steadily exist. At a time of non-active communication, the signals from a plurality of interference source radio communication devices 2 are received in advance by an interference signal receiving section 6 as the pre-process mode, then a resultant interference correlation matrix RI is stored in a storing section 7, and then an interference wave receiving antenna weight WI used to receive selectively the transmission signals from the interference source radio communication devices 2 is prepared based on the resultant interference correlation matrix RI. At a time of communication, the operation goes to the receiving process mode to normally receive the signal by a signal separating section 9, and a variation of the interference wave component is detected by an interference wave level detecting section 8 based on a signal power received using the interference wave receiving antenna weight WI. When the interference wave appears or changes, a desired wave separating/receiving antenna weight used to reduce the interference by using a new interference correlation matrix is changed adaptively.
摘要:
A spatial filtering adaptable for an interference wave that appears unsteadily can be implemented and also an interference canceling ability can be increased even in a condition that the interference wave does not steadily exist. At a time of non-active communication, the signals from a plurality of interference source radio communication devices 2 are received in advance by an interference signal receiving section 6 as the pre-process mode, then a resultant interference correlation matrix RI is stored in a storing section 7, and then an interference wave receiving antenna weight WI used to receive selectively the transmission signals from the interference source radio communication devices 2 is prepared based on the resultant interference correlation matrix RI. At a time of communication, the operation goes to the receiving process mode to normally receive the signal by a signal separating section 9, and a variation of the interference wave component is detected by an interference wave level detecting section 8 based on a signal power received using the interference wave receiving antenna weight WI. When the interference wave appears or changes, a desired wave separating/receiving antenna weight used to reduce the interference by using a new interference correlation matrix is changed adaptively.
摘要:
A wireless network system including a first terminal for sending a request-to-send signal including information on a medium use period to a second terminal before sending data, receiving a clear-to-send signal from the second terminal, and sending data to the second terminal during the medium use period; the second terminal for receiving the request-to-send signal and sending the clear-to-send signal; a third terminal for receiving the request-to-send signal and transmitting data to a fourth terminal during the medium use period; ant the fourth terminal. Thus, it is possible to prevent occurrence of a problem that when it is judged that the wireless channel is being used, transmission of the station is suppressed.
摘要:
A pulse signal is produced in a pulse generating section, and repetitively transmitted from an antenna at constant time intervals. A reception signal, received through an antenna and including a reflective wave from an object, is amplified and gain-adjusted. Thereafter, a distance detecting section detects a reception pulse of the reflected wave, and calculates the distance to the object. The variable attenuator attenuates the reception signal by a gain adjusted in accordance with a gain control signal. The gain of the variable attenuator is controlled so as to be maximum immediately after the pulse signal is transmitted, and to be reduced with elapse of time. Based on a gain adjustment timing signal, a gain adjustment timing when the attenuation amount is changed is made different for each transmission of the pulse signal.
摘要:
Wireless communication apparatus adopting a time division duplex system for transmission and reception using plural antennas, deviation of amplitude and phase occurring between transmission and reception circuits is detected and corrected using a communication signal. Channel estimation means detects channel information based on reception output of N reception circuits having a one-to-one correspondence with N antennas. Correction value detection means finds a correction value for correcting deviation occurring between each of N transmission circuits and each of the N reception circuits based on the channel information. A wireless communication apparatus transmits an already known signal (training signal) to a base station with which the wireless communication apparatus conducts communications. The base station executes channel estimation based on the already known signal and generates and transmits a correction signal (probe signal). The correction value detection means of the wireless communication apparatus detects the correction value using the correction signal.
摘要:
A radar receiver has plural antenna system processors each for performing coherent integration on the basis of correlation values between a reception signal and a transmission signal using correction amounts for phase variations corresponding to plural Doppler frequencies, plural correlation matrix generators for generating, for each of the plural different Doppler frequencies, correlation matrices which are pieces of phase difference information relating to an arrangement of reception antennas on the basis of sets of outputs of the coherent integration, respectively, an adder for adding together outputs of the plural correlation matrix generators, and an incoming direction estimator for estimating an incoming direction of reflection waves on the basis of outputs of the adder.
摘要:
A radar apparatus transmits a radio frequency transmission signal from a transmitter antenna in a given transmission period, and receives a signal of a reflected wave reflected by a target via a receiver antenna. The radar apparatus includes a transmission signal generator that generates a first transmission signal obtained by modifying a code having a third sub-code sequence and a fourth sub-code sequence coupled to each other in a first transmission period, and generates a second transmission period obtained by modifying a code having a fifth sub-code sequence and a sixth sub-code sequence coupled to each other in a second transmission period, and a transmitter RF unit that converts the first and second transmission signals into radio frequency transmission signals, and transmits the radio frequency transmission signals from the transmitter antenna.
摘要:
A radio communication apparatus capable of alleviating a burden in setting a transmission format and suppressing increases in the scale of the apparatus. In this apparatus, space multiplexing adaptability detection section (108) detects space multiplexing transmission adaptability for divided bands (DB-1 to DB-Nd) obtained by dividing a communication band to which Ns subcarrier signals belong in multicarrier transmission and to which a plurality of subcarrier signals belong, and outputs the detection results (#1 to #Nd). Transmission format setting section (110) sets a transmission format when carrying out radio transmission based on the detection results (#1 to #Nd) from space multiplexing adaptability detection section (108).
摘要:
A wireless communication system capable of removing a transmission signal to a different terminal space division multiplexed, an interference signal, in a terminal when wireless communications are conducted using space division multiple access is provided. A base station apparatus sends a notification of dedicated data transmission to a space division multiplexed terminal MSm and also sends a notification of information concerning a transmission beam used in a different terminal space division multiplexed and information concerning signal power used in the different terminal normalized in the terminal MSm. Based on the sent information, each terminal MSm calculates interference cancel weight according to MMSE criterion as the weight to maximize SINR and a reception signal is multiplied by the obtained interference cancel weight for decreasing the interference component and then the signal is detected by maximum likelihood estimation based on information of signal constellation transmitted for receiving spatially multiple-transmitted signal.