683results about "Line-of-sight transmission" patented technology

A visible light communication apparatus enables an operator to visually recognize a communication state during visual light communication. The apparatus includes a light emitting section which emits visible light and which includes a modulator, a visible light emitter, a light emitting element and an emission control section which includes a controller and which controls an emission state of the visible light from the light emitting section. The apparatus controls the emission state according to the communication state. It is hence possible for the operator to visually perceive the communication state during the visible light communication.

For an information terminal to be operated by users for collecting predetermined pieces of information from remote information devices by free-space optical communication, the present invention provides a technique for suppressing the power consumption of the information terminal by minimizing the amount of calculation performed to collect the aforementioned information. According to the present invention, each information device emits ID light on which a low-frequency pilot signal is superimposed. The information terminal captures a series of frames of images including the ID light and locates the ID light within the images by the following steps: (1) creating multiple levels of binned images having different resolutions for each frame of the image; (2) calculating an evaluation index for each pixel within a target range of the binned images at each level, from the lowest to the highest resolution, where the target range is narrowed every time the process switches over to a lower level. In (2), the evaluation index is calculated by an evaluation function including fast Fourier transformation performed throughout the series of frames of images. The evaluation index thus calculated is compared with a threshold to determine whether the pixel concerned is receiving ID light. The present technique significantly reduces the number of pixel to be analyzed and evaluated, thereby decreasing the total number of arithmetic operations to be performed using the evaluation function. Thus, the power consumption is suppressed.

Optical communication apparatuses capable of performing appropriate communication according to a distance to a receiving apparatus, optical communication methods, and an optical communication system are provided. A transmitting apparatus transmits an optical signal corresponding to data. The transmitting apparatus modulates intensity of the optical signal into intensity corresponding to a distance over which the data is to be delivered and outputs this intensity-modulated optical signal. This allows the transmitting apparatus to change the intensity of the optical signal corresponding to the data according to a distance to a receiving apparatus that receives the data, which thus allows the receiving apparatus to surely receive the data.

The present invention provides a camera-equipped cellular terminal capable of receiving visible light communication. In order to receive information from visible light, a light receiving unit (24) for visible light pointing to the same direction as a light receiving lens of the camera (21) is provided other than a camera (21) of a conventional camera-equipped cellular terminal (20). This light receiving unit (24) receives information from the visible light. This light receiving unit (24) may be configured by a photodiode or the like. When the camera (21) is used as a finder to display an illuminating device conducting visible light communication in a display of the camera, whether the light receiving unit 24 can receive information through visible light communication is determined.

An illuminating light communication device, which is for establishing a communication system capable of controlling fluctuation in intensity of illuminating light when transmitting data using a power line and illuminating light, and satisfactorily carrying out communication using the power line and communication using the illuminating light, is provided. When data is transmitted through the power line, a signal component is extracted by a filter unit 12, and the demodulated by a power line modulator-demodulator 13, thereby retrieving the data. The retrieved data is temporarily stored in a protocol converter 14. Afterward, the data is converted to the optical communication protocol, and blinking or amount of light of a semiconductor light emitting element 16 is controlled according to the data transmitted from a light source control unit 15, thereby modulating the illuminating light. This allows transmission of data utilizing the illuminating light. Multiple-valued PPM, which defines that existing pulses correspond to OFF while no pulse corresponds to ON, may be used as a modulation system for optical communication.

The invention relates to a cellular communication system based on a central main unit, a primary-cell communication unit connected to the central main unit, and a number of secondary-cell communication units. Each secondary-cell unit is connected to the primary-cell unit via a respective wireless optical link. The secondary-cell communication units are preferably remote radio units in a distributed radio base system, where each remote radio unit forms a distributed radio base station together with the central main unit. The wireless optical link quality is measured to detect reduced link availability. The invention compensates for insufficient link availability by providing adequate radio coverage from another communication unit within the cellular system and re-directing the radio traffic to that communication unit. Adequate radio coverage from another communication unit within the cellular system and re-directing the radio traffic to that communication unit. Adequate radio coverage is accomplished either by dynamically increasing the radio coverage or using a micro-macro cell architecture.

An optical-information transmitting, lighting apparatus 2 is installed in a place where a lighting apparatus of the existing type for applying light generally used is provided. The lighting apparatus 2 comprises an illumination light source 4 for applying light and an information-transmitting unit 5 for transmitting optical information. A person who may receive information from the lighting apparatus 2 has a mobile terminal 3, which receives the optical information transmitted from the information-transmitting unit 5. Since the lighting apparatus of the existing type is widely used in our living space. Hence, the optical-information transmitting, lighting apparatus 2 can convert every place where an existing type lighting apparatus is used, into an optical communications space.

A communication system (1) is provided with: a first communication apparatus (100a); and a second communicating apparatus (100b), the first communicating apparatus is provided with: (i) a displaying device (110) which can perform high-speed modulation; (ii) a display dividing device (112) for dividing a display surface of the displaying device into a plurality of display blocks; and (iii) a controlling device (115) for controlling the displaying device to display a display pattern in each of the divided plurality of display blocks, the second communicating apparatus is provided with: (i) a light receiving device (120) for light-receiving the display pattern which is displayed on the displaying device; and (ii) an obtaining device (121) for obtaining the predetermined data on the basis of the light-received display pattern.

For an information terminal to be operated by users for collecting predetermined pieces of information from remote information devices by free-space optical communication, the present invention provides a technique for suppressing the power consumption of the information terminal by minimizing the amount of calculation performed to collect the aforementioned information. According to the present invention, each information device emits ID light on which a low-frequency pilot signal is superimposed. The information terminal captures a series of frames of images including the ID light and locates the ID light within the images by the following steps: (1) creating multiple levels of binned images having different resolutions for each frame of the image; (2) calculating an evaluation index for each pixel within a target range of the binned images at each level, from the lowest to the highest resolution, where the target range is narrowed every time the process switches over to a lower level. In (2), the evaluation index is calculated by an evaluation function including fast Fourier transformation performed throughout the series of frames of images. The evaluation index thus calculated is compared with a threshold to determine whether the pixel concerned is receiving ID light. The present technique significantly reduces the number of pixel to be analyzed and evaluated, thereby decreasing the total number of arithmetic operations to be performed using the evaluation function. Thus, the power consumption is suppressed.

An apparatus is provided that includes a modulator and an optical transmitter coupled to the modulator and configured to emit an optical beam that the modulator is configured to modulate with data. The optical transmitter may thereby be configured to emit the optical beam carrying the data and without artificial confinement for receipt by an optical receiver configured to detect and recover the data from the optical beam. The optical transmitter may be configured to emit the optical beam with a divergence angle greater than 0.1 degrees, and with a photonic efficiency of less than 0.05%. The photonic efficiency may relate a number of photons of the optical beam detectable by the optical receiver, to a number of photons of the optical beam emitted by the optical transmitter.

An apparatus is described which uses directly modulated InGaN Light-Emitting Diodes (LEDs) or InGaN lasers as the transmitters for an underwater data-communication device. The receiver uses automatic gain control to facilitate performance of the apparatus over a wide-range of distances and water turbidities.

An illuminating light communication device is provided to construct a communication system in which, when data are transmitted by using an electric power line and illuminating light, light intensity fluctuations of the illuminating light are suppressed and communication by means of the electric power line and the illuminating light can be well carried out. When data to be transmitted are sent through an electric power line, signal components are extracted in a filter (12), they are demodulated in an electric power line modulating unit (13), so that data are obtained. The obtained data are tentatively stored in a protocol converting unit (14). The data are then converted to an optical communication protocol, a semiconductor light emitting element (16) is turned on or off, or its light quantity is controlled to modulate illuminating light in accordance with data to be transmitted by a light source controller (15). Thus, the data are transmitted by making use of the illuminating light. As a modulation system for the light communication, multiple-value PPM may be used, wherein an existing pulse is set to OFF while a non-existing pulse is set to ON.

An apparatus for a wireless transmission of high data rate signals such as received from an optical interface including gigabit fiber channel or a sonet. The architecture combines direct detection of the optical signal with clock and data recovery circuit and a differential signal encoder which is preferably a differential quadrature phase shift encoder and modulator pair. A millimeter wave, local oscillator and up conversion chain converts the optical input signal to a microwave carrier. In the opposite direction, the down converted signal is non-coherently phase detected and fed to a pair of synchronized clock and data recovery circuits to recover I and Q channel signals. These recovered signals are then combined prior to re-timing before they are fed back to the optical transceiver.

The present invention relates to the field of communications. Disclosed are a paging optimization method, device, and system, which ensure that a terminal normally receives a paging message sent by a system. The specific solution comprises: receiving a first paging message sent by a core network node, wherein the first paging message is used for paging a terminal; and in response to the first paging message, sending coverage enhanced control information and / or a coverage enhanced second paging message to the terminal. The present invention is used in a paging optimization process.

A transmission device includes a first light emission unit having a light source for emitting one optical signal. A reception unit includes an X-Y address system image sensor, having a pixel region including a plurality of pixels, for receiving the optical signal by the pixel region; a classification unit for creating classification information representing a pixel group including pixels, among the plurality of pixels, which are irradiated with the optical signal; and a control unit for controlling the X-Y address system image sensor in accordance with the classification information to simultaneously read signals of the pixels belonging to the pixel group.

An acquisition, pointing, and tracking (ATP) apparatus for free space optical (FSO) communications systems incorporates a multi-element detector array positioned at a focal plane of an optical telescope. An optical communications element lies at the center of the detector array. In lieu of traditional beam steering, the apparatus performs pointing and tracking functions internally by first calculating a position of an optical maximum on the detector array, and then translating the detector array within the focal plane of the telescope such that the optical communications element lies at the optical maximum for transmitting and / or receiving optical communications signals.

The invention provides an optical space transmission device by using an image sensor, aiming at realizing the high-speed communication for improving the signal read-out speed of the image sensor in the optical space transmission device by using the image sensor to reduce the tight optical axis adjustment. The ptical space transmission device transmits the optical signal from a transmission device to a a reception device, where the transmission device includes a first light emission unit having a light source for emitting an optical signal, the reception device including an XY address type image sensor having a pixel domain formed by a plurality of pixels and receiving an optical signal in the pixel domain, a classification unit for creating classification information for classifying pixels to which an optical signal is applied, into pixel groups, and a control unit for controlling the XY address-type image sensor according to the classification information and simultaneously reading out signals of pixels belonging to a pixel group.

A physiological function assisting device 1 is embedded in the body, and is provided with a transmitter 11 and receiver 12 for communicating with an external controller 2. External controller 2 controls embedded physiological function assisting device 1 from the outside. External controller 2 is provided with a transmitter 21 and receiver 22 for communicating with physiological function assisting device 1. Transmitters 11,21 modulate the plane of polarization of laser light, and emit the result as a transmission signal. Receivers 12,22 selectively receive light of a specific polarization state. Receivers 12,22 respectively output electric signals corresponding to the polarization state (polarization angle or ellipticity) of the received light. As a result, full duplex communications between a strongly dispersing medium like the human body and the outside is possible, while the power consumed by the internal device can be reduced.

In a data transmission method according to an exemplary embodiment, a data transmitter, which is capable of outputting a dummy light for judging an optical axis and a signal light having a beam spread smaller than that of the dummy light on the same optical axis, outputs the dummy light for scan so as to go across a photoreceiving part of a data receiver. When the dummy light having a predetermined optical level or more is optically received, the data receiver informs the data transmitter of reception chance and prepares for receiving the data. The data transmitter outputs the data carried by the signal light to the data receiver according to the information indicating the reception chance from the data receiver. The data receiver receives the data by optically receiving the signal light from the data transmitter.

A space-time division multiple-access (STDMA) laser communications (lasercom) system and related techniques. The STDMA system includes a plurality of remote nodes and an STDMA access node which uses precise electronic beam steering and beacons to provide access to each of a plurality of remote access nodes by means of both space and time-division multiple access.

A technique and a light emitting device that can smoothly read out data while tracking a position of the light emitting device (an object). The light emitting device expresses data with “a change in the change of a color (switching of changes)”. The light emitting device specifies an object and the position thereof with a first primary change and thereafter expresses data with, so to speak, a secondary change (switching of the primary change). The primary change means that G and B alternately turn on (indicated by G*B) and so on. The secondary change means a change from the condition (G*B), in which G and B alternately turn on, to the condition (B*R) in which B and R alternately turn on. Thus, since data is expressed by the change of color condition changes, it is easier to freely express data while the position of an object is specified.

The disclosure provides a practical system and methods for implementing an adaptive free-space optical network with a high-connectivity, dynamic mesh topology. The network can have operational characteristics similar to those of RF mobile ad-hock networks. Each node has one or more optical terminals that may utilize space-time division multiplexing, which entails rapid spatial hopping of optical beams to provide a high dynamic node degree without incurring high cost or high size, weight, and power requirements. As a consequence the network rapidly sequences through a series of topologies, during each of which connected nodes communicate. Each optical terminal may include a plurality of dedicated acquisition and tracking apertures which can be used to increase the speed at which traffic links can be switched between nodes and change the network topology. An RF overlay network may be provided to act as a control plane and be used to provide node discovery and adaptive route planning for the optical network.

A secure transaction method is provided for publicly-accessible transaction terminals. The method uses quantum key distribution (QKD) between a hand-portable QKD device and a complimentary QKD apparatus incorporated the transaction terminal. After the QKD device has been brought up to the transaction terminal, the QKD device and the complimentary QKD apparatus of the terminal are is used to provide the device and terminal with new secret shared random material. The new secret shared random material is then used to establish a secure classical communication channel between the device and transaction terminal for conducting a transaction. An ATM terminal and POS terminal that use quantum key distribution are also disclosed.

Disclosed is a visible ray communication system including a transmission apparatus and a reception apparatus, wherein the transmission apparatus includes: a plurality of light emitting devices; an S / P converter for serial-to-parallel converting transmission data, thereby generating N data streams; a modulator for modulating the generated N data streams for respective carriers with a predetermined number of dimensions, thereby generating N modulated signals; a carrier signal multiplier for multiplying the generated N modulated signals by orthogonal N carrier signals, respectively, thereby generating N transmission signals; and a light emitting control unit for illuminating the plurality of light emitting devices according to the generated N transmission signals.

Traditional satellite-to-earth data transmission systems are constrained by inefficient relay schemes and / or short-duration data transfers at low data rates. Communication systems described herein achieve extremely high burst rate (e.g., 10 Gbps or greater) direct-to-Earth (DTE) data transmission over a free-space optical link between a spacecraft and a remote terminal, which may be a ground terminal or another space terminal. The optical link is established, for example, when the remote terminal is at an elevation of 20° with respect to a horizon of the remote terminal. In some embodiments, a data transmission burst contains at least 1 Terabyte of information, and has a duration of 6 minutes or less. The communication system can include forward error correction by detecting a degradation of a received free-space optical signal and re-transmitting at least a portion of the free-space optical signal.

A laser scanner is located in a fixed position to have line-of-sight access to key features of monitored objects. The scanner rapidly scans pre-programmed points corresponding to the positions of retroreflecting targets affixed to the key features of the objects. The scanner is capable of making highly detailed scans of any portion of the field of view, permitting the exact location and identity of targets to be confirmed. The security of an object is verified by determining that the cooperative target is still present and that its position has not changed. The retroreflecting targets also modulate the reflected light for purposes of returning additional information back to the location of the scanner.

An adaptive optics imaging system has an acquisition imaging subsystem to assist in initial acquisition and alignment of the system to a target object. A wavefront sensor in the adaptive optics imaging system is aligned to a reference object in the acquisition imaging subsystem. The target object is also aligned to the reference object. In this way, alignment of the target object with the wavefront sensor is achieved.

An apparatus is described which uses directly modulated InGaN Light-Emitting Diodes (LEDs) or InGaN lasers as the transmitters for an underwater data-communication device. The receiver uses automatic gain control to facilitate performance of the apparatus over a wide-range of distances and water turbidities.

A conformal hybrid elctro-optical / radio frequency (EO / RF) aperture including an optical phased array (OPA) in a center portion of the aperture, and a variable inclination continuous transverse stub (VICTS) RF antenna surrounding the OPA using a plurality of continuous transverse stub (CTS) subarrays.