142 results about "Optical wireless" patented technology

An access point in an optical fiber-based high-speed optical wireless network is disclosed. The access point includes an antenna for receiving communication requirement signals, a switch for selectively outputting a corresponding signal according to the communication requirement signals, a bias control unit for selectively outputting bias current with variable intensity according to whether an output of the signal from the switch exists or not, on the basis of a threshold current; a bias operation unit for outputting input signals to the antenna when an input bias current is smaller than the threshold current and for outputting signals received by the antenna when an input bias current is larger than the predetermined threshold current, and a semiconductor optical amplifier for selectively performing an optical detection function of converting optical signals, which have been received through a first optical fiber from an central station, into electrical signals and sending the converted electrical signals to the bias operation unit, when a current smaller than the threshold current is input to the bias operation unit, and an optical modulation function of transmitting signals output from the bias operation unit through a second optical fiber to the central station, when a current larger than the threshold current is input to the bias operation unit.

A transmission system omits blanking signals from vertical and horizontal synchronizing signals for video data while securing synchronized transmission between a transmission side and a reception side. To achieve this, the transmission system transmits first synchronizing data (HV) for identifying vertical synchronization, second synchronizing data (HDp) for identifying and synchronizing an effective video line, pixel data for the effective video line, a required digital audio signal, and auxiliary control data. The transmission system can reduce a transmission capacity, optimize a transmission format for optical wireless transmission, and decrease a transmission speed.

In a free space communication network in which different communication nodes are linked together by directed beams, a method for dynamically configuring the topology of the network allows the transmission directions of the communication nodes to be autonomously changed to communicate with a new node as dictated by the needs of the network. Moreover, the nodes can be switched from directional to broadcast and back again on an as-needed basis. The network consists of a topology that can be rapidly and physically reconfigured as required to provide multiple connectivity, a desired quality of service, or to compensate with the loss of communication links between nodes. The loss of direct communication between any two nodes in an optical network can occur because of obscuration of the atmospheric path between the two nodes. The directed beam which provides the communication channel between the two nodes can, in this situation, be steered to direct its energy towards another accessible node.

The present invention offers systems and methods for effective multiple-hop routing, multicasting and media access control for vehicle group communications that employ directional wireless radio technology. Multi-beam optic-wireless media and streamlined operations provide low-overhead communications among vehicles. Systems and methods are provided to maintain a quasi-stationary group of neighboring vehicles, enable high-throughput on-demand switching among multiple vehicles, enable group coding in the vehicle group to achieve higher throughput, and enable dynamic adjustment of link to maintain desirable vehicle group. The proposed solution builds upon the conception of a MAC-free wireless operation and quasi-stationary vehicular switched network to achieve ultra-low-overhead and high-throughput vehicle communications.

A wireless communication method between mobile terminals using visible light and a mobile terminal therefore are disclosed. The method includes: periodically transmitting device discovery signals for searching for a visible light communication device when there is a request for a visible light communication; transmitting only reference clock signals between the device discovery signals; and connecting a link to a receiving terminal to transmit data when a response signal for the device discovery signal is received from the receiving terminal.

In a free space communication network in which different communication nodes are linked together by directed beams, a method for dynamically configuring the topology of the network allows the transmission directions of the communication nodes to be autonomously changed to communicate with a new node as dictated by the needs of the network. Moreover, the nodes can be switched from directional to broadcast and back again on an as-needed basis. The network consists of a topology that can be rapidly and physically reconfigured as required to provide multiple connectivity, a desired quality of service, or to compensate with the loss of communication links between nodes. The loss of direct communication between any two nodes in an optical network can occur because of obscuration of the atmospheric path between the two nodes. The directed beam which provides the communication channel between the two nodes can, in this situation, be steered to direct its energy towards another accessible node.

A method for transmitting wireless signals from a plurality of wireless access points (AP) to a train is disclosed in this invention. The method includes a step of connecting a high speed wide-area local area network (WLAN) switch between a network and a multiplexed Ethernet fiber system for receiving and transmitting a plurality of Internet signals to the plurality of wireless access points (AP). The method further includes a step of implementing a wireless signal receiving and distribution system on the train for processing a roaming and handover from receiving the plurality of signals from one of the wireless access point to a next wireless access point. The method further includes a step of distributing the plurality of signals to a plurality of passenger-users traveling on the train.

Certain implementations of the disclosed technology may include systems, methods, and apparatus for carrier-embedded optical radio-over-fiber (RoF) communications. Example embodiments of the method may include modulating a baseband signal with and an intermediate frequency (IF) and a radio frequency (RF) carrier signal to produce a RF modulated optical signal, transmitting the RF modulated optical signal to a remote access point with an optical fiber, and detecting the transmitted RF modulated optical signal. The method may also include receiving a RF uplink signal and mixing a harmonic of the RF carrier signal with the received RF uplink signal to down-convert the received RF uplink signal to an IF uplink signal. The method may include modulating a second optical source with the IF uplink signal to produce an IF uplink optical signal, transmitting the IF uplink optical signal via an optical fiber, and detecting the IF uplink optical signal.

A light emission section 13, including a light emitting element such as a semiconductor laser, emits a light beam in accordance with communication data. A light reception section 23, including a light receiving element such as a photodiode, receives the light beam emitted by the light emission section 13. According to the present invention, the light emission section 13 and the light reception section 23 are positioned and an emission angle and an incidence angle of the light beam are determined such that the light beam emitted by the light emission section 13 to the light reception section 23 is prevented from being reflected by a surface of the optical reception section 21 and / or a mounting substrate 22 and being returned to the light emission section 13.

An optical communication transmitter (13), receiver (15), and transceiver (17) having distinctive retro-reflective elements (30) and / or reflectivity that can be modulated. In one embodiment, the retro-reflective elements (30) can have different shapes or patterns (32), irrespective of rotation or size. In another embodiment, the retro-reflective elements can have their reflectivity modulated (42) to have a distinctive pattern in time. The solution also provides the capability to direct a remote optical receiver (15) to an available port (17) with an appropriate FOV. In the case where retro-reflective elements are only shape distinctive, a method may be used to direct the remote OWLink (15) to an appropriate port (17) of the hub (54). In addition to the hub ports (17) used for data links, additional hub ports called command ports (60) are added that are only used during the initial link setup of remote units. The hub (54) contains enough command ports (60) such that one command port covers each possible FOV. All command ports contain the same retro-reflective element shape that is very distinct from other hub shapes, e.g. the largest.

A technique for synchronizing the servo control systems between two optical wireless links (OWLs) that are in communication with one another. This synchronization allows the alignment in time of the various tasks to be assigned in a desired time period. The synchronization is not intended to synchronize the two OWLs down to the processor clock level, but rather at the servo sampling level, preferably to within a few percent of the servo sampling time. This synchronization may be advantageous in improving processor efficiency and control loop performance, and or improving system calibrations.

The invention provides a 60GHz millimeter wave-based optical wireless fusion video transmission system and method. According to the system, at a junction center, a single-arm Mach-Zehnder intensity modulator is adopted to generate optical millimeter waves through an optical carrier suppression manner, wherein the frequency of the optical millimeter waves is twice of that of radio frequency signals; then, downlink baseband data signals, i.e. high-definition television data stored in a DVD (Digital Video Disk), are modulated to the optical millimeter waves by using another electro-optical Mach-Zehnder modulator; the downlink signals are transmitted to a base station unit through an optical fiber link, and 60GHz electrical millimeter waves are generated from optical-millimeter-wave signals by a high-speed photolectric transducer, are amplified, and then are sent out by an antenna; and the optical-millimeter-wave signals received through the antenna by a user unit are reconstructed into downlink video baseband data signals by using coherent demodulation. According to the system, the radio frequency signals with the frequency of 29GHz are adopted to generate the optical millimeter waves with the frequency of 58GHz, the video transmission rate is 500Mb / s, the transmission distance for data in a downlink in monomode optical fiber at the transmission rate of 500Mb / s is 200m, and the wireless transmission distance can reach 5m.

A visible light communication system and an optical wireless LAN device are provided, which are capable of establishing a 10 Mbit / s LAN connection by means of an LED lighting unit which integrally has a plurality of LEDs. The optical wireless LAN device 2 has, a visible light transmission unit 202 for converting LAN data into visible light and transmitting same to the terminal device 3, and a light modulation unit 203 which lights an LED 204 constituting a lighting unit using a preset bias current. The LED 204 also has a red LED, a green LED, a blue LED, and a white LED integrally incorporated therein. The red LED performs transmission using visible light by going on and off and implements a 10 Mbit / s LAN connection.

A service providing system comprising a server device, a terminal device, and a service providing device in combination with an optical wireless tag device to achieve transmitting of ID, password, or other service information stored in the service providing device in a non-contact and non-broadcasting manner, thus enabling highly secured and reliable services.

An optical, line-of-sight modem. The modem includes a micro-mirror assembly including a micro-mirror and including an actuator for providing rotational movement to the micro-mirror, the micro-mirror being controllable by predetermined control signals. The modem includes a source of electronic data signals, and a source of light having a narrow beam of light directed at the micro-mirror. Means are provided for converting the electronic data signals to optical signals modulating the beam of light. Means are also provided for controlling the micro-mirror so as to maintain the micro-mirror in a predetermined position for data communication.

An optical wireless network includes an optical coupler for diverting received millimeter-wave signals comprised of an optical carrier and second order sidebands into multiple transmission paths; a downstream optical path being one of the multiple transmission paths and including an optical filter for filtering passing through the optical carrier with a single sideband, a converter for converting the optical carrier and single sideband to a corresponding electrical signal for amplification and broadcast transmission from an antenna; and an upstream path being one of the multiple transmission paths and having a filter for passing through the optical carrier only from the mm-wave signals and an intensity modulator driven by data received over the antenna to modulate the optical carrier for optical transmission to a receiving destination.

Reduced Rayleigh backscattering effect enables a longer-reach optical access communication network-thus it eliminates significant costs. Furthermore, a wavelength to an intelligent subscriber subsystem can be dynamically varied for bandwidth on-Demand and service on-Demand. A software module renders intelligence (and context awareness) to a subscriber subsystem and an appliance. An object can sense / measure / collect / aggregate / compare / map and connect / couple / interact (via one or more or all electrical / optical / radio / electro-magnetic / sensor / bio-sensor communication network(s) within and / or to and / or from an object) with another object, an intelligent subscriber subsystem and an intelligent appliance utilizing an Internet protocol version 6 (IPv6) and its subsequent versions.A construction of a near-field communication (NFC) enabled intelligent micro-subsystem and / or intelligent appliance with key applications (e.g., an intelligent, location based and personalized social network and an intelligent, location based and personalized direct and peer-to-peer marketing) are also described.

A system and method is disclosed for mitigating the scintillation and fading effects of baseband wireless, radio frequency wireless, optical wireless and satellite communication links. The system uses a space-time channel model to derive an optimal processing architecture for signal recovery through a scintillation channel. The signal power is collected by space-time sampling within the four dimensional volume of the spatial and temporal spread. Consequently, the space-time equalizer can effectively recover the lost signal power induced by the spreading effects of atmospheric scintillating medium. The advantages of this invention include a decrease in link outages resulting in higher link availability and more reliable data network services.

The invention discloses a near-field optical wireless high-speed simple interactive communication system and method used between electronic devices. Transmitted data information is transmitted to the opposite side through photo-electric conversion and with light serving as an information carrier, the opposite side restores light signals into electric signals through a photoelectric detector, and accordingly high-speed communication between the devices is achieved. Due to limitations of the devices in the prior art, the maximum communication speed is 100Mbps, and the communication speed of the system far exceeds that of an existing near-field non-contact transmission method. The system and method can be applied to mobile phones, intelligent terminals, tablet computers, notebook computers and other electronic devices, information high-speed wireless interconnection can be achieved, and the system and method have the advantages that high speed is achieved, safety and confidentiality are achieved, environment protection is achieved, no radiation exists and interactive communication is achieved, and have great prospects in the field of information non-contact transmission between intelligent terminals in the future.

Optical wireless links automatically align themselves using feedback information that is transmitted over the light beams being aligned. Each link performs an acquisition routine in which its light beam is swept through a pre-defined pattern while transmitting its beam alignment information. When a link receives beam alignment information from a remote link, it updates its transmission to include the alignment information received from the remote link. At some point during the acquisition routine, the remote link will receive its own alignment information “echoed back” from the first link and will re-align its beam accordingly. At some point, each link will have received its own alignment information echoed back from the other link and will have aligned itself to that position. Data communication can begin at that point, or a more refined alignment step can then be performed. The alignment information can be based upon position, sample number, or time transmitted.

In an optical wireless network, where light beams are transmitted over-the-air, reflections of the transmitted light beams may cause a receiver of an optical wireless device to detect and subsequently lock onto the signal that it transmitted. By doing so, the network is effectively broken. A method and apparatus to detect the reception of reflected signals using minimal additional hardware and data is presented. Should a reflected signal be detected, the receiver is prevented from locking onto the signal, allowing the receiver to detect and subsequently lock onto light beams originating from other optical wireless devices.

A wireless pointing device includes a push button switch, an optical sensor circuit, and a processor. The processor is configured to transmit to the optical sensor circuit a logic high signal in response to depression of the push button switch for a period greater than or equal to the predetermined first period of time and to transmit a logic low signal in response to depression of the push button switch for a period less than the predetermined first period. The optical sensor circuit responds to the logic high signal by entering a power saving mode wherein an optical sensor in the optical sensor circuit is decoupled from a power source.

A system incorporating safety features, for optical power transmission to receivers, comprising an optical resonator having end reflectors and a gain medium, a driver supplying power to the gain medium, and controlling its small signal gain, a beam steering apparatus and a controller to control at least the beam steering apparatus and the driver. The controller responds to a safety risk occurring in the system, by outputting a command to change at least some of the small signal gain of the gain medium, the radiance of the optical beam, the power supplied by the driver, the scan speed or the scan direction and position of the beam steering apparatus, or to register the scan pose which defines the location of said optical-to-electrical power converter. The controller may also ensure a high overall radiance efficiency, and may warn of transmitted power not received by a targeted receiver.

A wake-up system for an input device having a circuit board inside it has a motion sensor mounted on the printed circuit board inside the input device. The motion sensor has a motion signal output and the wake-up system further include a detection circuit connected to the motion signal output. The detection circuit has a wake-up signal output. The input device can be an optical wireless mouse. The motion sensor may be a mechanical motion sensor such as a tilt sensor having a ball contact and stationary contacts. The stationary contacts may be printed directly on the printed circuit board. The ball contact and stationary contacts form an electrical switch and are gold-plated. The ball contact is conductive. The motion sensor may be sealed to avoid corrosion. The detection circuit detects a change of state of whether the electrical switch formed by the ball contact and stationary contact is opened or closed. A first embodiment can amplify the motion signal from the motion sensor and a second embodiment can detect a low signal from the motion sensor. Also disclosed is a method of waking up an input device such as a mouse and an input device comprising the wake-up system.

The invention relates to a multi-user visible light communication method and a multi-user visible light communication system. The method comprises the steps of generating a plurality of chaotic sequences for identifying different users in a multi-user visible light communication system; performing CSK modulation on bit information input by each user of a transmitting end, thus obtaining a three-dimensional transmission vector, including RGB information, corresponding to each user; modulating the transmission vectors for the second time by using the chaotic sequences corresponding to the users, thus obtaining transmission matrixes corresponding to the users, and transmitting the transmission matrixes to a receiving end via an optical wireless channel; receiving the matrixes transmitted by the optical wireless channel by the receiving end, demodulating the matrixes by using the chaotic sequences corresponding to the users, thus obtaining the three-dimensional transmission vectors, including RGB information, corresponding to the users; and demodulating each three-dimensional transmission vector to obtain the bit information transmitted by the corresponding user. According to the multi-user visible light communication method, the interference among users can be reduced, the reliability and security of the system can be improved, and the system capacity can be increased.

The invention discloses a multi-carrier multiplexing optical wireless link system and a digital pre-distortion method thereof. The multi-carrier multiplexing optical wireless link system comprises a data processor for conducting pre-distortion treatment on input signals, a polarization controller used for adjusting light carrier, an electrooptical modulator used for loading signals processed by the data processor to the light carrier, and a feedback processor used for processing output signals of the electrooptical modulator and feeding the output signals back to the data processor. The data processor and the polarization controller are respectively connected with the electrooptical modulator. The electrooptical modulator is connected with the feedback processor. The feedback processor is connected with the data processor. The multi-carrier multiplexing optical wireless link system improves the transmission quality of all the frequency components of frequency division multiplexing signals, restricts adjacent channel disturbance, improves the dynamic range of the transmission signals of the system, and can be used in radio frequency division multiplexing optical wireless systems of wide bands.

The invention discloses an RIS-assisted NOMA enabled VLC / RF hybrid network secure transmission method, which is characterized in that an optical access point is configured at the indoor top, and a relay node is arranged on a desktop right below the optical access point; the optical wave beam of the optical access point can cover the edge of the round table top furthest, so that the NOMA user on the ground cannot directly receive the signal sent by the optical access point, and then the relay node is utilized to relay and transmit the electric signal to a reconfigurable intelligent surface (RIS) after photoelectric conversion; then the RIS reflects the signal to the NOMA user, and the eavesdropping node eavesdrops the information of the user in the process; on the basis of analyzing channelstatistical characteristics of an optical wireless link and a radio frequency wireless link, the safety outage probability and strict positive safety capacity of the VLC / RF hybrid network during amplification forwarding and decoding forwarding transmission are obtained respectively. Simulation verifies that the performance of the secure transmission method provided by the invention is related tothe number of reflection element surfaces, indoor layout, optical access point characteristics and radio frequency transmission characteristics.

A wireless communication system, a wireless transmitting apparatus, and a wireless receiving apparatus which can be applied to all types of light sources and can be applied to a variety of fields, provided with a medium forming an information transmission source, a general light source made of for example a lamp or the sun or another natural light source or artificial light source, a wireless transmitting apparatus for making the polarization of the light from the light source uniform and controlling the polarization plane of an infrared ray, visible ray, UV ray, or other light (modulating the light in polarization) so as to superimpose other information invisible to the human eye on visual information due to general reflected light and transmitting the same as an optical wireless signal, and a wireless receiving apparatus for receiving the optical wireless signal transmitted from the wireless transmitting apparatus and able to determine a change in orientation of the polarization plane of the light as information of the signal.