Abstract: Provided is a signal cancellation method for a wireless communication system, including: splitting a transmitted signal to obtain a main channel signal transmitted on a main channel and an auxiliary channel signal transmitted on an auxiliary channel; performing digital domain channel characteristic matching processing on the main channel signal and the auxiliary channel signal respectively to obtain a main channel characteristic matched signal and an auxiliary channel characteristic matched signal; and combining the main channel characteristic matched signal and the auxiliary channel characteristic matched signal which are coupled to a receiving channel in order for signal cancellation. A signal cancellation device for a wireless communication system is also provided. Through the technical solution of the disclosure, the signal cancellation problem of a bandwidth can be solved better.

Abstract: Domino circuit and related architectures and methods for carrier aggregation. In some embodiments, a Domino circuit can include first and second signal paths for respective first and second frequency bands, and each signal path can be configured to present an approximately zero impedance to a signal in the other frequency band. The Domino circuit can further include a coupling circuit that couples the first and second signal paths, and configured such that the approximately zero impedance presented by the signal path to the signal in the other frequency band results in the signal in the other frequency band being substantially excluded from the signal path.

Abstract: A method and system for detecting and characterizing an input signal receive a signal having an in-phase (I) component and a quadrature-phase (Q) component. A first IQ sample of the signal is acquired at a first point in time, and a second IQ sample of the signal is acquired at a second point in time, Using one or more processors, a delayed complex conjugate multiply (DCM) is applied to the first IQ sample of the signal and the second IQ sample of the signal to produce a constant product having an in-phase (IC) component and a quadrature-phase (QC) component. A signal magnitude and a signal frequency are determined from the IC component of the constant and the QC component of the constant, using the one or more processors.

Abstract: Apparatus and methods for signal generation, reception, and calibration involving quadrature modulation and frequency conversion. Embodiments of the present invention provide extremely wide bandwidth, high spectral purity, versatility and adaptability in configuration, and ease of calibration, and are particularly well-adapted for use in integrated circuitry.

Abstract: According to an embodiment, a reception circuit is configured to receive a reception signal from a transmission circuit through a receiving AC coupling element. The transmission circuit transmits a transmission signal through a transmitting AC coupling element. The receiving AC coupling element is AC coupled to the transmitting AC coupling element. The reception circuit includes a variable gain amplifier, a hysteresis circuit and a first control circuit. The variable gain amplifier is configured to amplify the reception signal with a variable gain to output an amplified signal. The hysteresis circuit has hysteresis in an input/output characteristic, and is configured to output an output signal according to the amplified signal. The first control circuit is configured to control the gain so that an amplitude of the amplified signal approximates a reference amplitude.

Abstract: A method includes receiving a request to send data to a destination device. The method includes determining a value associated with QoS of a wireless network. The wireless communication device includes first SIM card information that enables first data delivery according to a first priority via the wireless network and second SIM card information that enables second data delivery via the wireless network according to a second priority at least at a first delivery rate. The method includes determining, based on the value, a throughput value and a first portion of the data to send with the first data delivery. The method also includes determining a second portion of the data to send to the destination device with the second data delivery based on the throughput value, where the second portion includes none of the data when the throughput value is greater than a threshold.

Abstract: Disclosed are a card socket device and an electronic apparatus including the same. The card socket device includes a seat portion configured to receive an attachable card; and one or more connection terminal portions formed in the seat portion and configured to form an electrical connection with one or more connection pads formed in a bottom surface of the attachable card, wherein the seat portion is configured such that a space accommodating the attachable card is upwardly opened.

Abstract: A wearable device is coupled to a band including multiple modular functional band links that are each electrically and mechanically connected to one or more other of the band links and/or the wearable device and include one or more electronic components. In various implementations, the wearable device may receive identifiers from each of the band links, determine functionality available using the identifiers, and communicate with the band links to utilize the determine functionality. In some implementations, the band links may include multiple different output devices and the wearable device may determine to provide an output pattern and signal the respective output devices according to the output pattern. In various implementations, the band links may include multiple different input devices and the wearable device may receive input indications from the input devices and perform an action based on a pattern in which the input indications were detected by the respective input devices.

Abstract: A method, system, and device provide power-efficient communications within the context of available power. Transmission and receipt data rates are scalable in accordance with output power available from a power source. Data is transmitted at a data rate determined, at least in part, by the available output power.

Abstract: A manufacturing method for manufacturing a protective case, includes steps: a reflective film is prepared; a first filter film, a second filter film, and a third filter film of a color filter film, and then a decorative film are laminated on the reflective film in sequence to form a multilayer film structure; and a plurality of couples of relative positions of opposite surfaces of the multilayer film structure are processed via a bidirectional processing machine, thereby forming a plurality of light transmission openings penetrating the reflective film and the decorative film and further penetrating at least one or zero of first filter film, the second filter film, and the third filter film. A rear plate including the plurality of light transmission openings, the reflective film, the color filter film, and the decorative film is formed accordingly.

Abstract: A phone case capable of measuring a distance to an object contains: an accommodating cover, a protective cover, and a cell. The accommodating cover includes a first orifice defined on a front end thereof and includes two locking tabs extending outwardly from two peripheral sides thereof and connecting with a smartphone. The protective cover connects with the accommodating cover and includes an aperture defined on a rear end thereof. A front end of the cell connects with a first printed circuit board (PCB) for measuring a distance to an object, and a rear end of the cell couples with a second printed circuit board (PCB) for controlling a power supply. The first PCB has an infrared ray (IR) receiver, and the second PCB has a charging connector electrically connected with the smartphone and has a button mounted on a bottom thereof.

Abstract: A protective implement for portable electronic devices such as, but not limited to, smartphones, tablets and laptops includes a set of self-holding protective members that fit tightly on the corners of an electronic device without the need for tools or adhesives. Each protective member fits onto a respective corner of the electronic device and includes a shell formed of a generally rigid material (e.g., plastic, polycarbonate, ABS, silicon, metals, or wood) and an inner shock absorbing material such as, but not limited to, a rubber-like material that frictionally engages the top and bottom of the electronic device at the corner. The shell may be structured to receive a U-shaped spring element to assist with holding the protective member on the corner of the electronic device.

Abstract: A switching module includes a common terminal, individual terminals connected to respective corresponding signal paths, and a switch portion that selectively switches and connects the common terminal to one of the individual terminals. The switch portion includes first switches and at least one second switch, each first switch being connected to the common terminal at one end portion within the switch, the at least one second switch being connected to the common terminal at one end portion via a connection wiring electrode provided on a wiring board. This does not allow directional connection between the one end portion of the second switch and the common terminal within the switch. Thus, mutual interference between a communication signal transmitted through the first switch and a communication signal transmitted through the second switch is prevented.

Abstract: A navigation signal transmitting apparatus and a location information providing apparatus are provided for reducing time of positioning with a positioning signal from an indoor positioning transmitter. When an information providing server recognizes a transmitter ID of a transmitter from a mobile phone, the server makes reference refers to database associated with the transmitter ID, and reads SVG map information associated with the ID (including information for displaying a map and information of a correspondence relation between the transmitter ID and the location of the transmitter on the map). When the server transmits data of the SVG map information to a base station, the base station wirelessly emits the data of the SVG map information. When the mobile phone detects arrival of the data, the mobile phone can obtain the location of the transmitter from the data in accordance with a browsing operation of a user of the phone.

Abstract: Embodiments of the present invention provide a wireless communications method, user equipment, a base station and a system, and relate to the field of wireless communications. The method includes: acquiring a frequency domain spreading factor, a symbol-level spreading factor and a transmission time interval-level spreading factor; and performing frequency domain spreading, symbol-level spreading and transmission time interval-level spreading on first to-be-sent information respectively according to the acquired spreading factors and sending first spread information; or, despreading, according to the acquired spreading factors, second spread information sent by a base station.

Abstract: A terminal apparatus, a base station apparatus, a communication method, an integrated circuit, and a radio communication system are provided that enable a base station apparatus and a terminal apparatus to determine parameters relating to an uplink reference signal and efficiently communicate with each other.

Abstract: A device converts between electrical duplex and optical signals. In one embodiment, such a device includes an echo cancellation circuit that reduces the echo from an incoming optical signal.

Abstract: A method, an apparatus, and a computer program product for data communication over a multi-wire, multi-phase interface are provided. The method may include providing a sequence of symbols to be transmitted on a 3-wire interface, each symbol in the sequence of symbols defining one of three voltage states for each wire of the 3-wire interface, driving all wires of the 3-wire interface to a common voltage state during a transition from a first transmitted symbol to a second transmitted symbol, driving each wire of the 3-wire interface in accordance with the second transmitted symbol after a predetermined delay. Each wire may be in a different voltage state from the other wires of the 3-wire interface during transmission of the each symbol. The common voltage state may lie between two of the three voltage states.

Abstract: This contactless electricity supply device, which contactlessly performs charging of the battery (28) of a vehicle, is provided with: an electricity transmission coil (12) disposed at a road surface; and an electricity reception coil (22) disposed in the vehicle. A foreign object detection coil (13) is provided to the upper surface of the electricity transmission coil (12), and on the basis of induced voltage arising at the foreign object detection coil (13) during a trial electricity supply, foreign objects between the electricity transmission coil (12) and the electricity reception coil (22) are detected.

Abstract: Described herein are techniques related to near field coupling and proximity sensing operations. For example, a proximity sensor uses a coil antenna that is utilized for near field communications (NFC) functions. The proximity sensor may be integrated into an NFC module to form a single module.

Abstract: A wireless communication system is disclosed. The system performs data transmission from a first terminal including N antennas to a second terminal including M antennas using spatially multiplexed streams (N and M are integers larger than or equal to 2).

Abstract: Systems and methods presented herein provide for locating user equipment (UE) in a wireless communication network. The system includes one or more wireless access points, wherein each wireless access point is operable to detect signal of a UE in the wireless communication network, and to train with the UE to establish a communication link with the UE. The system also includes a network processing element communicatively coupled to the wireless access points and operable to extract channel estimation and signal strength information of the UE from the wireless access points via said training with the UE, to compare the channel estimation and signal strength information of the UE from the wireless access points to stored signatures of the UE, and to determine a location of the UE in the wireless communication network based on the comparisons.

Abstract: Methods and devices for use with a multi-feed antenna used in a MIMO communication system are described herein. A method can include obtaining an antenna feed characteristic indicator associated with each of the feeds of the multi-feed antenna, and controlling how power is distributed among the feeds based on the antenna feed characteristic indicator associated with each of the feeds. An antenna feed characteristic indicator can be, e.g., an indicator of impedance matching, in which case power can be distributed among the feeds of the multi-feed antenna based on the indicators of impedance matching associate with each of the feeds. Power can also be distributed based on an indicator of link quality. Additionally, or alternatively, coding rate and/or modulation type can also be controlled for each of the feeds of the multi-feed antenna, based on one or more antenna feed characteristic indicators and/or one or more indicators of link quality.

Abstract: A UE, for an HSPA WCDMA system, equipped with a first and a second transmit antenna, and arranged to use one or more sets of pre-coding weights for transmission. The UE is arranged to receive instructions from a NodeB on the set or sets of pre-coding weights to be used, and to transmit a first and a second pilot signal, and to use a first set of pre-coding weights for the first pilot signal and a second set of pre-coding weights for the second pilot signal, where the first set of pre-coding weights is the same as the UE uses for transmitting a first data stream, and to use different spreading codes for the first data stream and for the first pilot signal.

Abstract: Embodiments are provided for cross-polarized antennas design with different down tilt angles that support versatile functionality, such as for MIMO or beamforming. An embodiment antenna circuit comprises a baseband signal processor, a pair of RF transmitters coupled to the baseband signal processor, a pair of PAs coupled to the RF transmitters, a 90°/180° hybrid coupler coupled to the RF transmitters, a pair of duplexers and two antennas coupled to the PAs. The two antennas are down tilted at different down tilt angles. A pair of signals is generated using the baseband signal processor, transmitted by the RF transmitters, and amplified using the PAs. Additionally, a 90° or 180° phase difference is introduced into the signals using the 90°/180° hybrid coupler. After the amplifying and introducing the phase difference, the signals are polarized at two different polarizations and down tilted at different down tilt angles using the two antennas.

Abstract: Embodiments of user equipment (UE) and methods for codebook subsampling for enhanced 4TX codebooks in 3GPP LTE wireless networks are generally described herein. In some embodiments, a physical uplink control channel (PUCCH) is configured for transmission of channel state information (CSI) feedback including a rank indicator (RI) and a precoding matrix (W1). The rank indicator (RI) and a precoding matrix (W1) are jointly encoded and codebook subsampling is performed for the enhanced 4Tx codebook for at least one of: PUCCH report type 5 (RI/1st PMI) in PUCCH 1-1 submode 1; PUCCH report type 2c (CQI/1st PMI/2nd PMI) in PUCCH 1-1 submode 2; and PUCCH report type 1a (subband CQI/2nd PMI) in PUCCH 2-1.

Abstract: A transmission scheme for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. According to the transmission scheme, a precoding weight multiplying unit multiplies a precoding weight by a baseband signal after a first mapping and a baseband signal after a second mapping and outputs the first modulated signal and the second modulated signal. In the precoding weight multiplying unit, precoding weights are regularly hopped.

Abstract: The present invention provides a data transmission device and method in a wireless communication system. The device comprises a processor which is connected with the M antennas and which is formed so as to generate data to be transmitted through the M antennas, on the basis of a precoding matrix; the precoding matrix is generated based on a plurality of matrices; and a first matrix, which is one matrix among the plurality of matrices, is selected from within a codebook for N antennas (where N<M).

Abstract: A reception device includes an estimating unit, a rank identifying unit, a stream-number determining unit, a precoding-matrix determining unit, and a transmitting unit. The estimating unit receives a known signal transmitted from a transmission device, and estimates a channel between the transmission device and the wireless communication device and a reception signal quality. The rank identifying unit identifies a rank of a propagation path based on the estimated channel. The stream-number determining unit determines the number of data streams based on the estimated reception signal quality and the identified rank. The precoding-matrix determining unit determines a precoding matrix based on the estimated reception signal quality and the determined number of data streams. The transmitting unit transmits information relating to the determined number of data streams and the determined precoding matrix to the transmission device.

Abstract: A system and method for a single spatial stream based multiple-input multiple-output (MIMO) communication system in wireless MIMO channels with a non-zero mean or a fixed component is provided which utilizes deterministic beamforming in the transmitter and deterministic combining at the receiver. For transmission and reception of a data over MIMO channels, the method and system avoids the requirement of knowledge of the instantaneous channel values at the transmitter and the receiver. By assuming perfect knowledge of the mean value of the channel matrix at the transmitter, a beamforming vector is obtained for the transmitter. The receiver utilizes deterministic receive weights which are chosen using the channel statistics.

Abstract: A method and an apparatus are provided for transmitting Channel State Information (CSI) having a reporting mode and being transmitted from a User Equipment (UE) over a PUSCH transmission in an Uplink (UL) cell associated with a Downlink (DL) cell in response to the UE receiving a Downlink Control Information (DCI) format that includes a CSI request field indicating CSI transmission corresponding to one of a plurality of CSI processes associated with measurements of respective reference signals. The method includes obtaining, from the CSI request field, an indication of a CSI process set for a CSI transmission; and transmitting the CSI for the CSI process set indicated by the CSI request field, wherein the CSI request field includes 2 bits of a first CSI process set having a first set of interpretations.

Abstract: Distributed signal field for communications within multiple user, multiple access, and/or MIMO wireless communications. In accordance with wireless communications, a signal (SIG) field employed within such packets is distributed or partitioned into at least two separate signal fields (e.g., SIG A and SIG B) that are located in different portions of the packet. A first of the SIG fields includes information that may be processed and decoded by all wireless communication devices, and a second of the SIG fields includes information that is specific to one or more particular wireless communication devices (e.g., a specific wireless communication device or a specific subset of the wireless communication devices). The precise locations of the at least first and second SIG fields within a packet may be varied, including placing a second of the SIG fields (e.g., including user-specific information) adjacent to and preceding a data field in the packet.

Abstract: Disclosed herein is a system, apparatus, and method for using an antenna system comprising individually configurable antenna circuitries in a wireless network device to simulate the standard MU-MIMO transmissions as specified in the IEEE 802.11ac standard with antenna beamforming. The individually configurable antenna circuitries can be configured to transmit radio frequency (RF) signals with specific radiation patterns including directional beam patterns. Client devices may be grouped and antenna circuitries may be configured in such a way as to minimize inter-user interference. Frequent sounding-channel state feedback cycles and associated overhead are obviated with antenna beamforming, and no change to standard-compliant client devices is necessary. A better overall performance compared to MU-MIMO based on DSP-based beamforming as specified in the IEEE 802.11ac standard is expected.

Abstract: A method is provided for transmitting data between a transmitter having M>=1 transmit antenna(s), and one or more receivers having a total of N>=2 receive antennas. In the method, the data are transmitted using OFDM/OQAM modulation having L>=1 subcarriers. The transmitted data are pre-encoded using a pre-encoding matrix, the size of which is M s N and which is dependent on a zero-forcing matrix and on a spatial multiplexing matrix.

Abstract: A communications apparatus and method are provided. The communications method for an apparatus capable of Carrier Aggregation (CA), wherein the apparatus includes a plurality of processing engines and antennas, includes the steps of determining whether the apparatus is configured in a single component carrier for a first group of the antennas; and activating a second group of the antennas if the apparatus is configured in the single component carrier.

Abstract: A method and an apparatus for transmitting broadcast signals thereof are disclosed. The apparatus for receiving broadcast signals, the apparatus comprises a receiver to receive the broadcast signals, a demodulator to demodulate the received broadcast signals by an OFDM (Orthogonal Frequency Division Multiplex) scheme, a frame parser to parse a signal frame from the demodulated broadcast signals, wherein the signal frame includes at least one service data, a time deinterleaver to time deinterleave each the service data, wherein the time deinterleaving is performed depending on a number of physical paths for each the service data, a damapper to demap the time deinterleaved data and a decoder to decode the demapped service data.

Abstract: Methods and systems are provided for use with wireless networks having one or more cell in which each cell includes a base station (BS), at least one relay station (RS) and at least one mobile station (MS). The at least one relay station can be used as an intermediate station for providing communication between the BS and MS. Methods are provided for allocating OFDM resources for communicating between the BS, RS and/or MS for example dividing transmission resources into uplink and downlink transmissions and methods of inserting pilot symbols into transmission resources used by the RS. In some embodiments on the invention, the methods are consistent and/or can be used in conjunction with existing standards such as 802.16e.

Abstract: A method for receiving data by a relay station (RS) in a wireless communication system includes: receiving radio resource allocation information via an R-PDCCH (R-Physical Downlink Control Channel); and receiving data from a base station (BS) via an R-PDSCH (R-Physical Downlink Shared Channel) indicated by the radio resource allocation information, wherein the radio resource allocation information includes information regarding an allocation of resource blocks in a frequency domain and information regarding an allocation of OFDM symbols in a time domain. Since the radio resource allocation information providing information regarding a time relationship between a control channel transmitted by the BS to a UE and a control channel transmitted by the RS to a UE connected to the RS is provided, the RS can reliably receive a signal transmitted from the BS in a backhaul link between the BS and the RS in a wireless communication system including the RS.

Abstract: A repeater system including bi-directional amplifier circuitry that is configured for repeating signals between at least one device and a first signal source. Receiver circuitry is coupled with the amplifier circuitry provides at least one signal associated with at least one of a device or the first signal source or a second signal source. Controller circuitry is configured for monitoring a parameter of a provided signal that is reflective of a property of a signal source or a device. The monitored parameter is used to make a determination of whether repeated signals associated with the first signal source will desensitize the operation of the second signal source. The controller circuitry is also operable for adjusting the power level of the signals that are repeated by the bi-directional amplifier circuitry based on the determination that repeated signals will desensitize the operation of the second signal source.

Abstract: A method and system facilitate communication between a constellation of satellites and a mobile platform-mounted mobile communicator. The method and system may include the use of a first antenna suited for operation using a first frequency band in a first geographic region and a second antenna suited for operation using either the first or a second frequency band in a second geographic region. The method and system may use a controller to determine which antenna to activate based on one or more of a geographic indicator or a signal indicator. The system used by the method to facilitate the communication may have one or more enclosures over the antennas and controller for mounting to a mobile platform.

Abstract: Methods, devices, routers and systems for a satellite-ready Satcom Direct router with simultaneous use of Inmarsat, SwiftBroadband, Swift 64, Ku-Band and Ka-Band satellite connections with intelligent traffic control, along with Wi-Fi access and 3G/4G cellular network connectivity. The router is compatible with existing Wi-Fi access points and is backward-compatible with 802.11b/g. Up to four or more simultaneous wireless networks can be supported, allowing multiple systems to operate on aircraft without additional wireless access points and providing 3G/4G network connectivity when the aircraft is on the ground. A downloadable Satcom Direct router mobile App provides on-board cabin services including one or more of moving maps, flight tracker and command and control of satellite links.

Abstract: A method and system for communication with a mobile platform is provided. An antenna system coupled to a transmitter for use in providing a communication channel to a mobile user includes a first linear transmit array of radiating horns, a second linear transmit array of radiating horns, and at least one reflector coupled to at least one of the first linear transmit array and the second linear transmit array, the at least one reflector configured to reflect illumination from the first and second linear transmit arrays to form a communication channel for the mobile user.

Abstract: Provided are a receiver, a transmitter and a radio communication method capable of using non-orthogonal multiple access while suppressing cost increase and processing delay. A mobile station 200A receives non-orthogonal signals, also receives a reference signal to be used for interference cancellation, and extracts the non-orthogonal signal addressed to the mobile station 200A from the received non-orthogonal signals by demodulating and cancelling the radio signal addressed to another mobile station. In addition, the mobile station 200A demodulates the extracted non-orthogonal signal addressed to the mobile station 200A on the basis of the reference signal. The reference signal is multiplexed in the same radio resource block as a resource block allocated to the non-orthogonal signals, and is multiplexed in the radio resource block only when at least one signal is scheduled in the radio resource block.

Abstract: A network element operating in an Optical Transport Network (OTN) network and configured to adaptively preconfigure OTN connections includes one or more ports, each port including hardware supporting an Optical channel Transport Unit level k (OTUk) configured to transport an Optical channel Data Unit level k (ODUk) or one or more Optical channel Data Unit level j's (ODUj's), j<k; wherein, when a port of the one or more ports is installed with an idle connection, the port is automatically preconfigured in either a connection mode for the ODUk or a trail termination mode for the one or more ODUj's based on existing OTN connections in the OTN network.

Abstract: In an example, the present invention includes an integrated system on chip device. At least a pair of laser devices are associated with a channel and coupled to a switch to select one of the pair of laser devices to be coupled to an optical multiplexer to provide for a redundant laser device.

Abstract: A system and method for calibrating an optical module. The optical module including a microprocessor with non-volatile memory is provided at a calibration station for measuring calibrated value of a device parameter against raw values starting from minimum value in each of multiple zones of a primary parameter with one or more secondary parameters at least being set to a basis calibration point to determine coefficients for generating a N-spline function for the multiple zones and multiple multipliers for each zone corresponding to multiple calibration points. The coefficients and multiple multipliers are stored in the non-volatile memory and reused respectively for calculating a basis calibrated value based on any current raw value of the primary parameter a N-spline function in particular zone and for determining a final multiplier by interpolation of the multiple multipliers associated with the one or more secondary parameters, leading to a calibrated value for any condition.

Abstract: There is presented an optical frequency domain reflectometry (OFDR) system (100) comprising a first coupling point (15) arranged for splitting radiation into two parts, so that radiation may be emitted into a reference path (16) and a measurement path (17). The system further comprises an optical detection unit (30) capable of obtaining a signal from the combined optical radiation from the reference path and the measurement path via a second coupling point (25). The measurement path (17) comprises a polarization dependent optical path length shifter (PDOPS, PDFS, 10), which may create a first polarization (PI) and a second polarization (P2) for the radiation in the measurement path, where the optical path length is different for the first and second polarizations in the measurement path. This may be advantageous for obtaining an improved optical frequency domain reflectometry (OFDR) system where e.g. the two measurements for input polarizations may be performed in the same scan of a radiation source.

Abstract: Disclosed herein is an apparatus and method for detecting an optical line fault in a Passive Optical Network (PON). The apparatus includes an optical distribution unit configured to, when a multiplexed signal of a downstream light signal and a monitoring light signal is input, distribute the multiplexed signal to an Optical Network Unit (ONU) of a first optical path and to a second optical path. An optical layer management unit is installed in the second optical path and is configured to set a time at which the monitoring light signal of the multiplexed signal provided to the second optical path is received to a starting time of monitoring light measurement, compare a monitoring light signal reflected and returned from the ONU with a signal pattern obtained when no fault occurs, and then determine whether a fault has occurred in a distribution network.

Abstract: A device for measuring optical signal-to-noise ratio (OSNR) of a wavelength division multiplexing (WDM) optical signal including multiple wavelength channels may include a tunable optical filter to select an optical wavelength channel of the plurality of optical wavelength channels. The device may also include a polarization controller to adjust a polarization state of the selected optical wavelength channel, and a control unit to compute the OSNR of the selected wavelength channel based on a target control point.

Abstract: A visible light communication apparatus includes a constant current circuit and a load circuit including light emitting elements connected to output terminals of the constant current circuit. Further, the visible light communication apparatus includes a load variation circuit configured to change load characteristics of the load circuit by electrically connecting to the load circuit, the load variation circuit including a series circuit of a diode and a resistor connected in series to the load circuit and a switching element configured to electrically connect or disconnect the load variation circuit to the load circuit in response to a binary communication signal.