Abstract: A station placement design method includes: extracting candidates for an installation location of a wireless base station from point group data in accordance with designated conditions for an installation location of a wireless base station; determining presence/absence of visibility between a plurality of designated wireless terminal stations and the candidates for an installation location of a wireless base station based on the point group data and generating a first list including information in which the candidates for an installation location of a wireless base station and wireless terminal stations determined to have presence of visibility for the candidates for an installation location of a wireless base station are associated with each other; generating a second list including information representing combinations of the candidates for an installation location of a wireless base station that enable all of the plurality of designated wireless terminal stations to be accommodated based on the first list

Abstract: An accommodation station transmission unit modulates light based on an RF signal to generate an optical signal and outputs the generated optical signal, a base station transmission unit demultiplexes the output optical signal for each of wavelengths, outputs the demultiplexed optical signals, converts the demultiplexed optical signals into electrical signals to demodulate the RF signal, outputs the demodulated RF signal, and each of first ports of a matrix operation unit including the plurality of first ports and a plurality of second ports and configured to use each of the first ports as a reference port and perform, on signals obtained by the reference ports, a BFN matrix operation of performing phase changes that are different for each of positions of the reference ports and cause each of phases of signals output from the plurality of second ports to have a linear inclination receives the demodulated RF signal and forms transmission beams in different directions for each of wavelengths by a plurality of tr

Abstract: An interference evaluation method for evaluating, over an area, radio-wave interference that occurs between a first radio station and a second radio station includes: a distinguishing step of acquiring information indicating topographic cross-sections of respective azimuths centered about the first radio station, and distinguishing the topographic cross-section into a segment in which there is visibility from the position of the first radio station and a segment in which there is no visibility from the position of the first radio station; and a specification step of specifying a position at which a desired interference amount is reached based on a distance between the first radio station and the second radio station in a segment distinguished as having visibility from the position of the first radio station, and specifying a position at which the desired interference amount is reached by evaluating the radio-wave interference for each square of an evaluation target region segmented into squares in a segment d

Abstract: A radio communication method performed by a radio communication device includes an inverse fast Fourier transform step of performing inverse fast Fourier transform on a digital electric signal associated with a downlink radio signal, a digital-to-analogue conversion step of converting the digital electric signal subjected to the inverse fast Fourier transform into a first analogue electric signal, an electro-optic conversion step of converting the first analogue electric signal into an optical signal, a step of transmitting the optical signal, a photoelectric conversion step of converting the transmitted optical signal into a second analogue electric signal, and a step of transmitting the downlink radio signal corresponding to the second analogue electric signal.

Abstract: Using an array antenna in which a spacing between adjacent antenna elements is constant, each of combinations of two antenna elements in positions symmetrical relative to a center of an array is connected by wire connections in two paths, and a path length between the antenna elements in the combination of two antenna elements is the same in all of the combinations: a phase adjustment amount is calculated for each wire connection aside from a reference wire connection on the basis of an arrival direction of a wireless signal received by one antenna element in the combination of two antenna elements and a re-radiation direction of a wireless signal transmitted as a re-radiated wave by the other antenna element corresponding to the one antenna element, taking into account a phase difference between a signal transmitted by the wire connections connected to the one antenna element and a signal transmitted by the reference wire connection; and phase rotation is applied to the signal transmitted by the wire connect

Abstract: Point cloud data between a base station device and a terminal station device is acquired as a point cloud data group. A radius of a first Fresnel zone defined by the base station device and the terminal station device at each position where the point cloud data group is acquired is calculated. A region specified by the radius at each position where the point cloud data group is acquired is scanned to detect the point cloud data, and a non-line-of-sight region is extracted. A ratio of a total area of all the extracted non-line-of-sight regions to an area of a region constructed by the first Fresnel zone is calculated. A received power is estimated based on the calculated ratio between the areas. Whether or not there is a line of sight between the base station device and the terminal station device is determined based on the received power.

Abstract: A derivation method includes: a transmission step of transmitting, to a wireless terminal, a first radio-wave signal according to an optical signal with a first wavelength and a second radio-wave signal according to an optical signal with a second wavelength; a communication start time information acquisition step of acquiring information on a first communication start time and information on a second communication start time; a reception time information acquisition step of acquiring information on a first reception time and information on a second reception time; a transmission time period derivation step of deriving a first round trip time and deriving a second round trip time; and an optical fiber length derivation step of deriving an optical fiber length, based on the first round trip time, the second round trip time, a group velocity or a group delay time of the optical signal with the first wavelength, and a group velocity or a group delay time of the optical signal with the second wavelength.

Abstract: In two-dimensional map information showing communication equipment installation structures on which communication equipment is installed, roads, and buildings, a narrow region between the buildings is detected based on a distance of an interval of the buildings adjacent to each other and a predetermined length and a connection line connecting the buildings is imparted to an opened portion of the detected narrow region, a line-of-sight detection line is extended with any one of the communication equipment installation structures set as a start point and the line-of-sight detection line is rotated around the start point, intersections of the line-of-sight detection line and a contour line of the building or the connection line is detected and the intersection at a shortest distance from the start point among the detected intersections is detected as a line-of-sight intersection, and, when the line-of-sight intersection and another line-of-sight intersection belong to the same building, a line-of-sight range lin

Abstract: Provided is a wireless relay system including multiple terminal station apparatuses and a base station apparatus. The base station apparatus includes: a base station reception unit that respectively receives pieces of upstream data traffic from the multiple terminal station apparatuses; an encoding unit that, if pieces of upstream data traffic that require mutual forwarding in opposite directions are present in the respective pieces of upstream data traffic, performs network encoding on the respective pieces of upstream data traffic such that the pieces of upstream data traffic are pieces of data traffic of mutually identical content; and a base station transmission unit that simultaneously transmits encoded data traffic as downstream data traffic to the multiple terminal station apparatuses.

Abstract: n wavelengths set such that delay differences between optical signals due to wavelength dispersion in an optical fiber between accommodation and base stations are at equal intervals are assigned to n antenna elements of the base station which are at predetermined intervals. The accommodation station adjusts the phases of optical signals of the wavelengths or modulated signals that modulate the optical signals such that the amounts of phase shift of their RF signals are at predetermined intervals. The accommodation station transmits beacon signals multiple times while varying a transmission phase shift interval ?1 and the terminal transmits beacon number information of a beacon signal selected based on received power multiple times.

Abstract: A derivation method is a derivation method performed by a communication system, including: a transmission step of transmitting a first radio-wave signal according to an optical signal with a first wavelength and a second radio-wave signal according to an optical signal with a second wavelength; a communication start time information acquisition step of acquiring information on a first communication start time and information on a second communication start time; a reception time information acquisition step of acquiring information on a first reception time that is a reception time related to the first radio-wave signal, and information on a second reception time that is a reception time related to the second radio-wave signal; and an optical fiber length derivation step of deriving a length of the optical fiber, based on the first communication start time, the first reception time, the second communication start time, the second reception time, a group velocity or a group delay time of the optical signal wit

Abstract: A communication system includes a central station device and a base station device. The central station device includes: a plurality of signal processing units, each generating an electrical signal of a wireless signal by performing signal processing corresponding to a wireless system; a conversion unit that generates an optical signal by performing intensity modulation on the electrical signal; and a signal processing control unit that controls the conversion unit to generate an optical signal in which a plurality of the electrical signals are multiplexed. The base station device includes: an electrical signal generation unit that receives the optical signal generated in the central station device via an optical transmission path and converts the received optical signal into a plurality of electrical signals; and a plurality of antenna devices, each wirelessly transmitting the wireless signal according to the electrical signal generated by the electrical signal generation unit.

Abstract: A method includes generating, based on data indicating the travel trajectory of a mobile object, which acquires point group data indicating the position of an object present in a three-dimensional space within a predetermined measurable distance, the measurable distance, candidate base station position data indicating a candidate position for installing a base station apparatus, and candidate terminal station position data indicating a candidate position for installing a terminal station apparatus, data indicating the positional relationship between the travel trajectory and a candidate base station position, and data indicating the positional relationship between the travel trajectory and a candidate terminal station position; generating data indicating a measurable range based on the travel trajectory data and the measurable distance; generating data indicating a connecting line segment connecting the candidate base station position and the candidate terminal station position based on the candidate base sta

Abstract: A station deployment support method includes a positional relationship identification step of, based on travel trajectory data of a mobile object that measures an object present in a three-dimensional space within a predetermined measurable distance and acquires point group data on the measured object, the measurable distance, candidate base station position data, and candidate terminal station position data, generating base station positional relationship identification data and terminal station positional relationship identification data; a measurable range identification step of generating measurable range data based on the travel trajectory data and the measurable distance; and a travel trajectory selection step of selecting at least one piece of travel trajectory data so that the proportion of the measurable range in a predetermined evaluation area satisfies a predetermined value.

Abstract: A first wireless communication apparatus assigns a pilot signal without an effective signal component at least in an adjacent frequency component to a generated transmit signal, and transmits the transmit signal including the pilot signal. A second wireless communication apparatus converts the received signal or a frequency-converted signal obtained by frequency conversion of the signal into a signal in a frequency domain, sets an approximate value of the distance between the second wireless communication apparatus and the first wireless communication apparatus, calculates a coefficient ?k, based on the approximate value of the distance, the effective bandwidth, the speed of light, the number of FFT points, and the frequency component number, extracts a signal in the frequency domain, generates a phase noise compensated sampling signal, and reproduces data transmitted by the first wireless communication apparatus.

Abstract: A base station apparatus includes a centralized station apparatus and a plurality of access points connected to the centralized station apparatus via optical fibers. Based on propagation delay times in the optical fibers, the centralized station apparatus performs grouping such that access points, among a plurality of access points, with a difference in propagation delay time within a threshold value, belong to the same group. The plurality of access points perform connection processing for each of the groups, to communicate with wireless terminals subordinate to the plurality of access points.

Abstract: An accommodation station transmission unit modulates light to generate an optical signal based on an RF signal and outputs the generated optical signal, a base station transmission unit obtains the optical signal from an input port, demultiplexes the obtained optical signal for each wavelength, outputs the demultiplexed optical signals from output ports of corresponding wavelengths from among a plurality of output ports allocated to each of the wavelengths of the light, and demodulates the RF signal by converting the optical signals output by the output ports into electrical signals, a plurality of transmission antennas emit the demodulated RF signal, and a reflect array or a transmit array receives the RF signal emitted by each of the transmission antennas and forms a transmission beam in a different direction for each position of the transmission antenna that is a transmission source of the RF signal for each RF signal.

Abstract: An accommodation station transmission unit modulates light based on an RF signal to generate an optical signal and outputs the generated optical signal, a base station transmission unit demultiplexes the output optical signal for each of wavelengths, outputs the demultiplexed optical signals, converts the demultiplexed optical signals into electrical signals to demodulate the RF signal, outputs the demodulated RF signal, and each of first ports of a matrix operation unit including the plurality of first ports and a plurality of second ports and configured to use each of the first ports as a reference port and perform, on signals obtained by the reference ports, a BFN matrix operation of performing phase changes that are different for each of positions of the reference ports and cause each of phases of signals output from the plurality of second ports to have a linear inclination receives the demodulated RF signal and forms transmission beams in different directions for each of wavelengths by a plurality of tr

Abstract: A wireless communication system which includes first and second wireless station apparatuses having a plurality of antenna elements and performs directivity forming. For T1 and T2 such that T2=N2×T0 and T1=N1×T2 with a predetermined period T0, the wireless communication system performs the steps of sequentially switching N1 types of directional beams at intervals of period T2 and transmitting signals while performing switching with an identical directional beam switching pattern maintained over period T1, sequentially switching N2 types of directional beams at intervals of period T0 and receiving signals over the period T1 or more while performing switching with an identical directional beam switching pattern maintained over the period T2, searching for a directional beam having a highest reception level among those acquired over a predetermined period, and setting the searched directional beam as a directional beam to be used.

Abstract: n wavelengths set such that delay differences between optical signals due to wavelength dispersion in an optical fiber between accommodation and base stations are at equal intervals are assigned to n antenna elements of the base station which are at predetermined intervals. The accommodation station adjusts the phases of optical signals of the wavelengths or modulated signals that modulate the optical signals such that the amounts of phase shift of their RF signals are at predetermined intervals. The accommodation station transmits beacon signals multiple times while varying a transmission phase shift interval ?1 and the terminal transmits beacon number information of a beacon signal selected based on received power multiple times.