Abstract: FSO systems rely on line-of-sight, and thus can be easily impaired due to disruptions such as atmospheric turbulence. There is a need for a more robust communication system allowing longer distances to be bridged and/or downtime to be reduced. An optical transmitter is provided generating at least one optical alignment beam. The transmitter comprises at least one alignment modulator, to modulate the alignment beam with transmitter directional data. A suitable receiver may demodulate this information and use the directional data from the transmitter to simplify the attainment and/or maintenance of a sufficient degree of alignment. Additionally or alternatively, the at least one alignment beam may be used to detect, characterize and/or monitor one or more environmental parameters.

Abstract: In an optical wireless communication system including: an optical wireless communication apparatus that moves along with a first optical wireless station; and a second optical wireless station opposed to the first optical wireless station, the optical wireless communication apparatus includes at least one reference light transmitting unit that transmits reference light to the second optical wireless station with a position in front in a moving direction of the first optical wireless station defined as a transmission position, the second optical wireless station includes a reference light receiving unit that receives the reference light transmitted from the at least one reference light transmitting unit, an estimation unit that estimates an influence of atmospheric air on transmission of signal light based on a reception state of the reference light received by the reference light receiving unit, a compensation unit that performs compensation processing on the signal light based on the influence of the atmosph

Abstract: A method of scheduling encryption key delivery communication sessions in a satellite quantum key distribution system comprising a constellation of one or more satellites and a plurality of user ground stations comprises producing a list of user ground stations requiring encryption keys. For each satellite of the constellation of satellites, determining a region of the earths surface within which the satellite can carry out encryption key delivery communication sessions to user ground stations using a quantum optical communications link during a scheduling period. Obtaining a cloud cover map. Comparing the locations of the listed user ground stations, the determined regions of the earths surface for the constellation of satellites, and the cloud cover map, to identify listed user ground stations to which encryption key delivery can be carried out by the constellation of satellites during the scheduling period.

Abstract: This optical communication device (1) is provided with: a plurality of light-receiving elements (11) configured to receive communication light, the plurality of light-receiving elements being provided so as to correspond to a plurality of channels; and a controller (15) configured to perform control to invalidate output from a light-receiving element that has received high-intensity light higher in light intensity than a predetermined value among the plurality of light-receiving elements.

Abstract: Integrated target waveguide devices and optical analytical systems comprising such devices are provided. The target devices include an optical coupler that is optically coupled to an integrated waveguide and that is configured to receive optical input from an optical source through free space, particularly through a low numerical aperture interface. The devices and systems are useful in the analysis of highly multiplexed optical reactions in large numbers at high densities, including biochemical reactions, such as nucleic acid sequencing reactions. The devices provide for the efficient and reliable coupling of optical excitation energy from an optical source to the optical reactions. Optical signals emitted from the reactions can thus be measured with high sensitivity and discrimination. The devices and systems are well suited for miniaturization and high throughput.

Abstract: The present disclosure provides a wireless charging device and method, and a device to be charged. The wireless charging device includes a first communication control circuit. The device to be charged includes a second communication control circuit and a battery. The first communication control circuit performs wireless communication with the second communication control circuit during wireless charging of the battery. The wireless communication may be one or more of Bluetooth communication, Wi-Fi communication, short-range wireless communication based on a high carrier frequency, optical communication, ultrasonic communication, ultra-wideband communication and mobile communication.

Abstract: A portable communication device includes a USB interface that is connectable to and disconnectable from an external USB port of a computing device by a user for enabling Internet access service to the computing device. In an example application, the portable communication device may include a wireless communication component with baseband and radio components. Upon connecting the portable communication device to the external USB port of the computing device by the user, the portable communication device activates wireless Internet service with protected data stored in the portable communication device, and the computing device is thereby enabled with wireless mobile Internet access on the go. The portable communication device may further provide Internet sharing feature to other wireless devices over a local wireless communication link that may be compatible to a protocol within IEEE 802.11. The portable communication device may be configured as an adapter sized dongle.

Abstract: The disclosure describes a system that includes a self-driving system for operating a vehicle autonomously, one or more optical transmitters mounted on the vehicle, and one or more computing devices in communication with the self-driving system and the one or more optical transmitters. The one or more computing devices are configured to operate the self-driving system to cause the vehicle to approach a designated location in proximity of a structure on which one or more receivers are mounted and determine that the one or more optical transmitters have an alignment with the one or more receivers. Then, the one or more computing devices are configured to operate the one or more optical transmitters to establish an optical communication link with the one or more receivers and transmit data to the one or more receivers over the optical communication link.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may receive a multi-UE wake-up signal in a downlink control information (DCI) communication. The DCI communication may include a set of content field groups. The UE may identify a content field group of the set of content field groups that is to be read by the UE, and determine a behavior associated with performing a UE wake-up operation based at least in part on the identified content field group. Numerous other aspects are provided.

Abstract: An apparatus includes a reflector having one or more reflective faces and an opening. The reflector is selectively movable into and out of an optical path of an alignment beam. When the reflector is located within the optical path of the alignment beam, (i) the one or more reflective faces are configured to reflect a first portion of the alignment beam and (ii) the opening is configured to allow passage of a second portion of the alignment beam through the reflector. The reflector may include a retro-reflector, the retro-reflector may include multiple reflective faces, and the multiple reflective faces may be positioned around the opening.

Abstract: In the mobile communications of the fifth generation or the like, a radio relay apparatus capable of stably over a wide area realize a three-dimensional network, in which a propagation delay is low, a simultaneous connection with a large number of terminal apparatuses in a wide-range and high-speed communication can be performed, and a system capacity per unit area is large, in radio communications with terminal apparatuses including devices for the IoT, and there is no influence on radio wave frequency resources, is provided.

Abstract: Apparatus for and method of transmitting an optical signal by a Free Space Optical, FSO, communication system, the method comprising: transmitting, by an optical signal transmitter (104), an optical signal (700) into at least part of a volume of an optical medium (302); and controlling, by a controller, the optical signal transmitter (104), to scan the at least part of the volume (302) using the optical signal (700) in a sequence of non-overlapping loops (704, 708). The sequence of non-overlapping loops (704, 708) may be a sequence of non-overlapping, concentric circular loops.

Abstract: A lighting device is disclosed. The lighting device comprises: a solid-state lighting element; a radio frequency communication unit for wireless communication between the lighting device and an external device; a light guide having a circumferential edge, wherein the light guide is adapted to couple in light emitted by the solid-state lighting element and to provide illumination to the surroundings of the lighting device; and a metal strip extending along at least a portion of the circumferential edge of the light guide, wherein the metal strip is in thermal contact with the solid-state lighting element and the light guide, and wherein the metal strip is coupled to the radio frequency communication unit so as to operate as an antenna for the radio frequency communication unit.

Abstract: A gateway device of a wireless lighting system includes a transmitter configured to transmit network information wirelessly at a first power level and pair with one or more wireless nodes based on the network information transmitted by the gateway device at the first power level. The transmitter is further configured to transmit the network information wirelessly at a second power level after transmitting the network information wirelessly at the first power level, where the second power level is greater than the first power level.

Abstract: According to an example aspect of the present invention, there is provided an apparatus (201) comprising adjustable optical equipment (290), a position sensitive photodetector (280), at least one light emitter (220), and control circuitry (104) configured to cause the light emitter (220) and the adjustable optical equipment (290) to output from the apparatus (201) a divergent beam of light, to determine a location of a light signal on the position sensitive photodetector (280) and to cause at least one of the at least one light emitter (220) and the adjustable optical equipment (290) to output from the apparatus (201) a collimated beam of light to a direction selected based at least in part on the location of the light signal on the position sensitive photodetector (280).

Abstract: Provided are methods and systems for improved user tracking via the exchange of information over narrow-beam infrared (IR) transmission. IR receivers are positioned around a venue. A limited-range, narrow-beam IR transmitter associated with a user sends IR signals that are received by the IR receiver when the IR transmitter is close enough to the receiver. The receiver then transmits signal data from the received signal to a back-end location tracking system (LTS) that aggregates and processes the received signal data as a detection event. Based on the detection event, the LTS determines the location of the IR receiver hence the location of the user. Because of the limited transmission range of the IR transmitter, analyzing the detection event allows precise determination of the user's location, orientation, and/or movements within the venue. The LTS can also determine the identity of the user.

Abstract: Optical communication systems and methods using coherently combined optical beams are disclosed. A representative system includes a first mirror having a first actuator for adjusting a position of the first mirror in a path of a first optical beam and a first optical detector for receiving light reflected from the first mirror. The system also includes a second mirror having a second actuator for adjusting a position of the second mirror in a path of a second optical beam and a second optical detector for receiving light reflected from the second mirror. The system includes an interferometer for measuring an interference between the first and second optical beams and a third optical detector for receiving light from the second interfered optical beam. Intensity of the first interfered optical beam is increased by the interference, and intensity of the second interfered optical beam is decreased by the interference.

Abstract: Light is used to communicate between objects separated by a large distance. Light beams are received in a telescopic lens assembly positioned in front of a cat's-eye lens. The light can thereby be received at various angles to be output by the cat's-eye lens to a focal plane of the cat's-eye lens, the position of the light beams upon the focal plane corresponding to the angle of the beam received. Lasers and photodetectors are distributed along this focal plane. A processor receives signals from the photodetectors, and selectively signal lasers positioned proximate the photodetectors detecting light, in order to transmit light encoding data through the cat's-eye lens and also through a telescopic lens back in the direction of the received light beams, which direction corresponds to a location upon the focal plane of the transmitting lasers.

Abstract: A system for communicating between an object in space and a ground station, between objects in space, or between ground stations, includes a telecentric lens. Photodetectors positioned upon a focal plane of the telecentric lens detect an inbound light beam, received from a source, that has passed through the telecentric lens to the focal plane. Lasers positioned upon the focal plane transmit light beams from the focal plane through the telecentric lens to an area that includes the source of the inbound light beam. A processor detect signals from individual photodetectors corresponding to light detected, and selectively signals individual lasers that are close to those photodetectors, resulting in a returning beam that arrives close to the source, and which carries encoded data.

Abstract: A lighting device includes: a metal casing; a power supply circuit which is disposed in the metal casing and supplies power to a light source; an antenna disposed in the metal casing; a radio circuit which is disposed in the metal casing and receives a radio signal via the antenna; a control circuit which controls the power supply circuit according to the radio signal received by the radio circuit; at least one opening that communicatively connects an inside and an outside of the metal casing; and a line which is inserted in the at least one opening and insulated from the metal casing, the line being conductive and having open ends.

Abstract: A method and system for controlling and monitoring street lights using optical link signaling through free space which does not require an FCC license for operation. The optical link signaling is accomplished in the space between street lights by using LEDs for both area lighting and optical signaling. A Street lighting system luminaire comprises a structural member such as a pole, a lamp comprising one or more LEDs, and an optical receiver that receives optical signaling from one or more other luminaires in street lighting network. The modulator modulates the output of the lamp to launch data into the street lighting system for transport. The optical receiver and modulator enables strobing and flashing modes such as required to support emergency services.

Abstract: Systems and devices for controlling at least one entertainment device include at least one remote in two-way communication with a base device. Memories of the remote and the base device are operable to store substantially the same data as the other such that if the remote or base device fails, data in the memory of the non-failing device is loaded into a memory of a replacement device. A memory of a second remote may also store the same data as the remote memory such that if either the first remote or the base device fails, data in the memory of the second remote is loaded into a memory of a replacement device.

Abstract: Systems for determining a location of a portable device are provided. The system includes stationary infrared (IR) base stations, portable devices and at least one radio frequency (RF) transceiver. At least two of the IR base stations receive timing synchronization information and transmit corresponding IR location codes in a time period based on the received timing synchronization information. Each IR location code is representative of a location of the corresponding IR base station. Each portable device detects the IR location codes and, if one of the IR location codes is detected, transmits an output signal including a portable device ID representative of the portable device and the detected IR location code. The RF transceiver periodically provides, upon a request, the timing synchronization information to the respective IR base stations relative to a unified time of origin.

Abstract: A unitary handheld portable module includes a keypad for entering data and a display for displaying data. A base module is configured to be coupled with and communicate through a telephone line and includes a keypad for dialing a telephone number and a display for displaying information. The portable and base modules are configured to have a mounted configuration in which the portable module is removably mounted on the base module and covers the base module's display, and the modules communicate with each other for the portable module's display to display information relating to operation of the base module.

Abstract: A laser relay module for free space optical communications including an optical telescope for receiving and transmitting optical beams; an optical diplexer for separating transmitting and received optical beams; an optical amplifier; a modulated beacon laser for line of sight control of a plurality of communicating remote network nodes; a beacon beam detector for detecting an incoming beacon optical beam for line of sight control of the optical telescope and receiving data from other network nodes; and means for inserting an output of the modulated beacon laser into the optical telescope for transmission to another network node, and for transporting the incoming beacon optical beam to the beacon detector.

Abstract: An apparatus and a method for providing synchronized data by using visible light communication includes, receiving a synchronization channel from a mobile communication base station using a specific mobile communication network, by a Light Emitting Diode (LED) lighting; analyzing the received synchronization channel, and extracting a synchronization signal for synchronizing the LED lighting with at least one LED lighting adjacent to the LED lighting; selecting a specific time slot of the synchronization signal based on IDentifications (IDs) of the LED lightings; and including a data frame of the LED lighting in the specific time slot, and transmitting the specific time slot, which includes the data frame of the LED lighting, to a mobile terminal.

Abstract: A system comprises a transmitter including a laser configured to generate a laser beam directed at a spot on a surface, and a laser driver connected to the laser and configured to modulate input data onto the laser beam. The system may further comprise a receiver including an optical detector configured to decode received light into raw data, a signal processor configured to decode the raw data into the original input data, and telescope optics configured to receive light reflected from the spot on the surface, collimate the light and converge the light onto the optical detector.

Abstract: A free space optical communication system (100) and method including: several optical beam expanders (414) for receiving incoming optical signals from ground sites and neighboring satellites; several optical preamplifiers (412) for preamplifying the received optical signals; one or more optical main amplifiers (404) for amplifying the preamplified optical signals; and an optical switch (408) for directing respective amplified optical signals to respective destinations via a respective optical beam expander. The respective amplified optical signals are inputted to a respective optical beam expander (414) for transmission to said respective destinations, as outgoing optical signals.

Abstract: Techniques are disclosed for providing spatially-defined and/or distance-defined light-based communications within a vehicle/roadway environment. In some embodiments, the techniques can be used to vary the data content of a given transmitted light-based communications signal based on factors such as position, distance, and/or proximity of the transmitting source and the receiver. In some embodiments, the techniques can be used to vary the processing or other handling of a received light-based communications signal based on one or more of such factors. In some instances, the disclosed techniques can be utilized to tailor light-based vehicle-to-X (V2X) communications for dissemination between and among vehicles and infrastructure in a vehicle/roadway environment. To that end, a node may host a transmitter (e.g., laser, LED, or other solid-state light source) configured to emit such light-based communication signals and/or a receiver (e.g.

Abstract: A free space optical communication system (100) and method including a constellation of several satellites (102). Each of satellites including: several inter-satellite optical telescopes (204) for optical communication with multiple neighboring satellites, each inter-satellite optical telescope is capable of adjusting its elevation angle; and several up/down link optical telescopes (206) for optical communication with multiple ground sites. As the constellation passes a given ground site, some of the up/down-link telescopes of a given satellite are configured to track at least two respective ground optical telescopes of the given ground site and send data to the ground optical telescope with the clearest line of sight to the given satellite. Moreover, each of the satellites includes optical circuitry (208, 210, 212, 216) for optically processing and switching incoming and outgoing optical signals without converting the optical signals into electrical signals.

Abstract: A method includes receiving a transmitted code via visible light communication from a light source. The transmitted code is decoded using a translation table. The translation table indicates raw data corresponding to the transmitted code as well as a duty cycle corresponding to the transmitted code.

Abstract: A laser relay module for free space optical communications including an optical telescope for receiving and transmitting optical beams; an optical diplexer for separating transmitting and received optical beams; an optical amplifier; a modulated beacon laser for line of sight control of a plurality of communicating remote network nodes; a beacon beam detector for detecting an incoming beacon optical beam for line of sight control of the optical telescope and receiving data from other network nodes; and means for inserting an output of the modulated beacon laser into the optical telescope for transmission to another network node, and for transporting the incoming beacon optical beam to the beacon detector.

Abstract: A system, method, and optical communication device are disclosed. The system can include a plurality of optically coupled nodes forming an optical communication network. Each node may include an array of pixel elements, each pixel element having an optical detector and an active optical source. The pixel array may be disposed in a backplane of a lens that is configured to map incoming optical signals to pixel locations in the backplane according to their respective angles of incidence and to minimize a deviation at each pixel location between incoming optical signals arriving at the optical detector and emissions from the optical source. The node may include a processor and memory. The processor can register senders in the optical network at locations in the pixel array and can generate routing information by which to route communications from the registered senders to other pixel elements for transmission to their respective destinations.

Abstract: An optical repeater in a mobile communication system includes a main hub unit (MHU) and a plurality of repeaters connected to a plurality of access points of the MHU, respectively. Each of the repeaters receives subcarrier information and a signal transmitted from a base station, as optical signals, through the MHU or a different repeater connected thereto, processes only a signal corresponding to a subcarrier allocated to a terminal which has accessed according to the subcarrier information, and transmits the processed signal to the terminal which has accessed. Also, each of the repeaters maps a signal of the terminal which has accessed to a subcarrier allocated to the terminal which has accessed, and transmits the same to the MHU or a different repeater connected thereto.

Abstract: The invention relates to base stations in communication networks. In more particular the invention relates to cellular base stations such as 3G/4G and WLAN base stations. Some or all of the aforementioned advantages of the invention are accrued with a fully photonic base station (200) that powers itself with solar photons, provides radio network access and relays an optical photonic beam (220, 221, 230, 231) through air encoded with the data from radio signals of computer users and mobile phone users to the Internet and the global telecommunication network. A system engineer can build a network with the inventive base stations in a matter of days. He simply walks to the roof of houses and points the optical beams to other base stations in adjacent houses.

Abstract: Methods and systems for relaying an optical signal from a remote control to a remote-controlled device such as a home entertainment device or a security device. Embodiments include at least one optical receiver and a plurality of optical transmitters. The optical transmitter positioned with an unobstructed line-of-sight to the home entertainment device is identified and the data encoded in the optical signal from the remote control is sent to that transmitter. A second optical signal that is substantially identical to the first is then generated at the optical transmitter and communicated to the home entertainment device.

Abstract: An optical transmission system is described. The transmission system comprises a plurality of modules that include signal repeaters at each end. Within each module, optical signals are propagated between the repeaters through free space. Adjacent modules are connected by optical fibers to enable optical transmission therebetween. Adjacent modules are mechanically coupled with a flexible joint.

Abstract: An optical relay system is provided, which includes a first optical signal distribution device (101), a phase detection device (103), an amplitude regeneration device (102), and a phase regeneration and load device (104). An optical relay method is further provided, which includes the following steps. A received input signal is divided into two paths; phase information of one path of the input signal is extracted, and is converted to an amplitude modulated signal; an amplitude of the other path of the input signal is restored, so as to generate an amplitude regenerated signal; a phase is loaded on the amplitude regenerated signal by using the amplitude modulated signal, so as to generate a phase regenerated signal. The system and method eliminate a phase noise of the signal in a transmission process, improve a transmission performance of the signal, and realize a simple implementation method.

Abstract: A sortation system has a track forming a continuous loop, an article-conveying car positioned on the track and configured to move along the track, a system controller, a communication station positioned near the track for communicating with the article-conveying car and the system controller, a portable bin positioned adjacent the track, the portable bin comprising a bin communication device configured to wirelessly transmit bin status information to the article-conveying car when the car is proximate to the bin, where the article-conveying car is configured to wirelessly relay received bin status information to an off-car communication device at the communication station when the car is proximate to the communication station, and where the bin communication device is attached to the portable bin, and the portable bin is operably positionable substantially anywhere along at least a portion of the track. Additionally, the car may wirelessly transmit instructions and information to the bin.

Abstract: Aspects of the present invention provide a multi-band hybrid Gigabit wireless communication system which is enabled by a number of different complementary access technologies to realize ubiquitous hyper-connectivity, true broadband, seamless operation and low power consumption. The system is capable of serving fixed, nomadic and mobile scenarios. The multi-band wireless system is a low power wireless system which operates in different frequency bands covering the spectrum from radio wave to optical wave by making use of both regulated bandwidths and unregulated bandwidths. Using low power distributed antenna and low power indoor and outdoor antennas enables the use of unregulated bandwidths as well as regulated bandwidths as the low power nature of the signals reduces the possibility of interference with the regulated use of the signals.

Abstract: A system comprises a transmitter including a laser configured to generate a laser beam directed at a spot on a surface, and a laser driver connected to the laser and configured to modulate input data onto the laser beam. The system may further comprise a receiver including an optical detector configured to decode received light into raw data, a signal processor configured to decode the raw data into the original input data, and telescope optics configured to receive light reflected from the spot on the surface, collimate the light and converge the light onto the optical detector.

Abstract: A sortation system where control and operation is facilitated by a contact-free, wireless communication configuration. Wireless communication is accomplished in a line-of-sight (LOS) manner while the cars of the sortation system are continuously moving along the track at operational speed. Each car is configured to operate independently with respect to how a car is instructed to accept and deliver packages. The sortation system provides for the cars to act as messengers between the bin stations and the system controller with respect to the status and health of the bin stations.

Abstract: A repeater is disclosed that transmits an optical signal using wave division multiplexing. The repeater includes a demultiplexing unit that separates plural channels contained in the optical signal, an adjusting unit that adjusts at least optical power of each of the channels according to a control signal, a multiplexing unit that outputs a multiple wavelength signal in which the channels are multiplexed, and a monitoring unit that determines a modulation scheme and a bit rate of the optical signal for each of the channels so as to generate the control signal.

Abstract: Provided is a network system for controlling devices which operate in response to an infrared signal. The network system includes modules and a home server. The modules output the infrared signal for controlling the devices in response to command data or analyze path information of the command data, forward the command data to next one of the modules, and receive infrared control signals generated by the devices. The home server includes ID numbers of the modules and the path information of the command data for allowing the command data to reach each of the modules and outputs the command data or receives the infrared control signals. Therefore, the network conveniently control the devices using the infrared control signal even when the modules are too distant from the home server for the infrared signal to reach the devices at a time or obstacles are placed in front of the modules.

Abstract: An optical transmission system is described. The transmission system comprises a plurality of modules that include signal repeaters at each end. Within each module, optical signals are propagated between the repeaters through free space. Adjacent modules are connected by optical fibers to enable optical transmission therebetween. Adjacent modules are mechanically coupled with a flexible joint.

Abstract: A free-space optical communications network for allowing a plurality of geographically-distributed users to communicate may include free-space multi-channel relay converters for tracking a plurality of users, and a connection system in communication with each of the plurality of multi-channel relay converters. The connection system may include an internal alignment reference and steering mirrors. Each free-space multi-channel relay converter may be adapted to align with the internal alignment reference. The connection system may be adapted to align the plurality of free-space multi-channel relay converters with one another to allow the plurality of geographically-distributed users to communicate.

Abstract: A data transmission network comprising: a base comprising: a base light source and a base light detector; a plurality of nodes, each node comprising a node light source and a node light detector; and a plurality of optical fibres arranged to form a optical fibre network. Each optical fibre is arranged to receive light from the base light source, transmit the light received from the base light source to one or more of the node light detectors via an air gap, receive light from one or more of the node light sources via an air gap, and transmit the light received from the node light source(s) towards the base light detector.

Abstract: Provided are an image processing system and method thereof which communicates with an external image source device, the image processing system including: a display device which receives a modulated remote control signal modulated by a modulation method and demodulates the modulated remote control signal to generate a demodulated remote control signal and transmits the demodulated remote control signal; and a relay device which receives the demodulated remote control signal and modulates the demodulated remote control signal according to the modulation method to output an output remote control signal to the external image source device.

Abstract: Methods and systems for determining a location and an identity of a portable device are provided. The system includes apparatus for transmitting timing synchronization information, a plurality of stationary infrared (IR) base stations and a plurality of portable devices. Each IR base station is configured to receive the timing synchronization information and to transmit a corresponding IR location code in a time period based on the received timing synchronization information. Each portable device is configured to: 1) receive the timing synchronization information, 2) detect the IR location codes from the IR base stations and 3) transmit an output signal including a portable device ID representative of the portable device and the detected IR location code. Each portable device is synchronized to detect the IR location code in the time period based on the received timing synchronization information.

Abstract: A bridge controller, which controls relay between terminals including emission units and addresses assigned to the terminals, acquires coordinates of a light-received element in an light receiving unit at which light emitted from an emission unit is received, and stores the acquired coordinates in a location information table memory in association with a logical location on the network. Thereafter, it is determined whether or not the stored coordinates differ from newly acquired coordinates. When it is determined that the stored coordinates differ from the newly acquired coordinates, the logical location associated with the coordinates stored in the storage unit is controlled to be changed and stored.