Nippon Telegraph and Telephone Corporation

Daisei Uchida

Yusuke Asai

Yosuke Fujino

Ryo Miyatake

Shuki Wai

Tatsuhiko Iwakuni

Naoki Kita

Kazuto Goto

Takafumi Fujita

Hideyuki Tsuboi

Kento Yoshizawa

Hideki Toshinaga

Masahiro Umehira

Yasuo Suzuki

Hayato Fukuzono

Takatoshi Sugiyama

Keita Kuriyama

Masafumi Yoshioka

Toshifumi Miyagi

Kazunori Akabane

Osamu Kagami

Satoshi Kurosaki

Takuto Arai

Provided is a wireless communication system using a single-carrier multi-value modulation scheme, the wireless communication system aiming at preventing erroneous transmission of data and securing a high data rate while utilizing a non-linear region of an amplifier. A reception apparatus acquires, from a transmission apparatus, a specification related to an input/output characteristic of a transmission signal amplifier and transmission power of data transmission. On the basis of the specification and the transmission power, a constellation of signal points is estimated. A reception point, which is a point in constellation coordinates, of a reception signal is detected, and likelihood calculation for the reception point is performed with respect to the signal points. A symbol intended by the reception point is identified on the basis of a result of the likelihood calculation.

Wireless communication system, wireless communication method, and reception apparatus

A wireless communication apparatus includes a terminal selection unit that selects one or more user terminals, a prediction unit that derives a prediction value of an interference amount of a stream group transmitted from a plurality of antennas for the selected one or more user terminals, a collection unit that, when the prediction value of the interference amount is less than a threshold value, collects reception power values of streams included in the stream group from the selected one or more user terminals, an antenna selection unit that selects the plurality of streams in descending order of reception power values and selecting the plurality of antennas associated with the plurality of selected streams, and a transmission unit that transmits the plurality of selected streams by beam forming using the plurality of selected antennas.

Wireless communication apparatus and wireless communication method

The present invention performs: generating base station positional relationship specification data indicating a positional relationship between travel trajectory and a base station candidate position, and terminal station positional relationship specification data indicating a positional relationship between the travel trajectory and a terminal station candidate position, based on travel trajectory data indicating the travel trajectory of a moving body for measuring an object present in a three-dimensional space within a measurable distance predetermined and acquiring point cloud data indicating a position of the object measured in the three-dimensional space, the measurable distance, base station candidate position data indicating a candidate position for installing a base station apparatus, and terminal station candidate position data indicating a candidate position for installing a terminal station apparatus; and specifying a reliability coefficient indicating a degree of reliability of a processing result of a prescribed evaluation processing performed based on the point cloud data, based on the base station positional relationship specification data and the terminal station positional relationship specification data generated.

Station placement assistance method, station placement assistance apparatus and station placement assistance program

A communication method determination apparatus includes a comparison unit and an instruction unit. The comparison unit obtains a bit string of a portion of a physical header for synchronization from a wireless frame that includes the physical header for synchronization in which information for synchronization in a physical layer is set and a physical data portion in which data of a higher-level layer than the physical layer is set, and compares the obtained bit string with a bit string pattern specific to a communication method targeted for determination. The instruction unit performs communication method determination processing for determining whether or not the communication method targeted for determination is used for the wireless frame, based on a result of comparison. If it is determined that the communication method targeted for determination is not used for the wireless frame, the instruction unit changes the communication method targeted for determination, instructs the comparison unit to newly obtain a bit string of a portion that follows the obtained bit string, from the physical header for synchronization, and to compare the newly obtained bit string with a bit string pattern specific to the post-change communication method targeted for determination, and performs the communication method determination processing again.

Communication scheme determination apparatus, communication scheme determination method and program

A line-of-sight determination method includes: a point cloud data acquisition step of acquiring point cloud data including a first position indicating a position of a first wireless station and a plurality of second positions indicating positions on a structure serving as a candidate in which a second wireless station opposing the first wireless station is to be installed; and a line-of-sight determination step of determining whether or not there is a line of sight between the first position and at least one of the second positions, and determining whether or not there is a line of sight between the first wireless station and the structure based on the determination result. In the line-of-sight determination step, if it has been determined that there is no line of sight between the first position and a first second position of the second positions, it is not determined whether or not there is a line of sight between the first position and a second second position among the second positions, the second second position being located in the vicinity of the first second position.

Perspective determination method, perspective determination apparatus and program

An interference wave arithmetic operation method performed by a wireless communication system including a plurality of antennas, the method including: determining an interferer antenna on the basis of information regarding directivity, a position, and an orientation of each of the plurality of antennas; and calculating interference wave reception intensity of a victim antenna using an interference wave from the determined interferer antenna.

Interference wave calculation method, interference wave calculation apparatus, computer program

A control device of the present invention is for provision in a gateway device that includes multiple communication units that perform wireless communication with terminal devices using different communication methods. Based on communication unit individual information that is acquired from the communication units and includes information indicating at least characteristics of the communication methods of the communication units, operations of the communication units are scheduled so as to prevent the overlapping of periods in which the communication units perform signal transmission/reception with the terminal devices.

Control apparatus, control method, and control program

A radio communication system includes a transmission device which transmits a plurality of radio signals, and a reception device which receives the plurality of radio signals from the transmission device and estimates, as a carrier frequency offset, a difference between a carrier frequency transmitted by the transmission device and a reference reception frequency used for reception. The system includes the transmission device which branches a first previously determined sequence of training signals, and transmits the radio signals modulated with frequencies by the carrier frequency offsets having regularity for a first sequence of a plurality of branched training signals, and the reception device which estimates the carrier frequency offset with the transmission device according to the first sequence of training signals included in the radio signals transmitted from the transmission device and phase shift amounts obtained from the first previously determined sequence of training signals.

Radio communication system, transmission device, reception device, radio communication method, transmission method, reception method

A wireless transmitting apparatus inserts a training signal into a transmission burst at fixed symbol intervals as a pilot signal, a wireless receiving apparatus performs AD conversion of a received burst signal, performs symbol timing recovery, performs frame position detection and pilot signal extraction from the received burst signal for which symbol timing was established, performs frame synchronization, and performs a carrier frequency estimation using pilot signal. A carrier frequency estimation is also performed with respect to a received burst signal for which frame synchronization was established, and channel distortion is estimated and output based on a frequency-corrected received burst signal. Channel distortion estimation is then performed with respect to a frequency-corrected received burst signal, and a data symbol sequence of the channel-compensated received burst signal is converted to a received data bit stream.

Wireless transmitting apparatus, wireless receiving apparatus, wireless transmission method, wireless reception method, wireless communication system, and wireless communication method

An OFDM signal communication system used in broadband mobile communication, achieves stable operation under severe frequency selective fading environments, giving high quality. The OFDM signal communication system which transmits OFDM signals over the same radio frequency from N transmitting antennas, has an inverse matrix computer for computing an N&#xd7;N inverse matrix constituted by propagation coefficients for respective propagation paths between each of N transmitting antennas and each of N receiving antennas, and a subcarrier demodulator which separates the signals of the respective propagation paths, based on the obtained inverse matrix.

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Yokohama, Japan

Daisei Uchida