Abstract: A wireless receiver includes a down converter module operable to deliver a signal having a signal bandwidth that changes over time, a dynamically controllable filter module having a filter bandwidth and fed by said down converter module, and a measurement module operable to at least approximately measure the signal bandwidth, said dynamically controllable filter module responsive to said measurement module to dynamically adjust the filter bandwidth to more nearly match the signal bandwidth as it changes over time, whereby output from said filter module is noise-reduced. Other wireless receivers, electronic circuits, and processes for their operation are disclosed.

Abstract: Aspects of the disclosure provide an apparatus for receiving a circularly polarized signal by linearly polarized antennas. A horizontally polarized antenna and a vertically polarized antenna of the apparatus receive a circularly polarized signal that is transmitted based on a transmitted baseband signal vector. A radio frequency (RF) module of the apparatus generates a first baseband signal vector based on the received circularly polarized signal. The first baseband signal vector includes a product of the transmitted baseband signal vector and a receiving polarization vector of the transmitted baseband signal vector. Processing circuitry of the apparatus estimates the receiving polarization vector of the transmitted baseband signal vector based on the first baseband signal vector. The processing circuitry derives a second baseband signal vector based on the estimated receiving polarization vector and the first baseband signal vector.

Abstract: An electronic device according to an embodiment includes a housing including at least one opening; a support member in the housing; a display disposed on the support member; a first printed circuit board including a plurality of layers; a first wireless communication circuit disposed on a first surface of the first printed circuit board; a feeding structure on another surface of the first printed circuit board electrically connected to the first wireless communication circuit; and a waveguide configured to transmit a signal provided from the first wireless communication circuit to an outside of the housing, and the waveguide extends along one surface of the support member from the feeding structure. Other embodiments are possible.

Abstract: According to one embodiment, a transformer-based in-phase and quadrature (IQ) includes a differential balun having a first inductor and a second inductor. The first inductor has a first input terminal and a first output terminal. The second inductor has a second input terminal and a second output terminal. Additionally, the IQ generator circuit includes a third inductor magnetically coupled with the first inductor. The third inductor has a first isolation terminal and a third output terminal. The IQ generator circuit also includes a fourth inductor magnetically coupled with the second inductor. The fourth inductor has a second isolation terminal and a fourth output terminal. The IQ generator circuit additionally includes a first transistor coupled to the first input terminal of the first inductor. Further, the generator circuit includes a second transistor coupled to the second input terminal of the second inductor.

Abstract: A radio frequency circuit includes a first radio frequency circuit, a second radio frequency circuit, and a first switch circuit. The first switch circuit includes a first terminal connected to an antenna connection terminal, a second terminal connected to the first radio frequency circuit, and a third terminal connected to the second radio frequency circuit. The first radio frequency circuit includes a first power amplifier circuit supporting a first power class, and a first filter circuit connected to the first power amplifier circuit and having a passband that includes a first band. The second radio frequency circuit includes a second power amplifier circuit supporting a second power class having a maximum output power greater than a maximum output power of the first power class. The second radio frequency circuit includes a second filter circuit connected to the second power amplifier circuit and having a passband that includes the first band.

Abstract: Systems, methods, and computer-readable media for synchronizing oscillators. A system can include a plurality of oscillators comprising at least a first oscillator and a second oscillator. The system can also include a plurality of antennas comprising at least a first antenna and a second antenna. Further, the system can include a first oscillator synchronizer coupling the first oscillator to the first antenna. The first oscillator synchronizer can be operative to perform a first synchronization of a first time base of the first oscillator to a second time base of the second oscillator based on a first mutual coupling signal. The first mutual coupling signal can represent a first interaction between the first antenna and the second antenna.

Abstract: A switch module is disclosed, the switch module comprising a first node; a plurality of second nodes; a plurality of series switches; a plurality of signal paths, each signal path defined between one of the plurality of second nodes and the first node and having one of the plurality of switches disposed therebetween, wherein one or more series switches are in a closed state at a time defining one or more active signal paths; and one or more shunt switches coupled between at least one of the signal paths and ground and configured to be in an open state when that signal path is one of the active signal paths.

Abstract: The present disclosure provides a method (400) for facilitating Antenna Calibration, AC. The method (400) includes: identifying (410) a leakage signal from a signal received at an AC signal receiver and resulted from a reference signal originated from an AC signal transmitter passing through an AC signal path from the AC signal transmitter to the AC signal receiver; and cancelling (420) an influence of the leakage signal on an AC process.

Abstract: Wireless communication devices, systems, and methods related to mechanisms for transmitting and receiving reference signals in a high-speed train (HST) single frequency network (SFN). A base station (BS) determines a first frequency pre-compensation value for a reference signal transmitted via a first transmission and reception point (TRP) and a second frequency pre-compensation value for a reference signal via a second TRP. The BS notifies a user equipment (UE) of the first and second pre-compensation values through at least one of the TRPs. The BS applies the first pre-compensation value to the reference signal via the first TRP and the second pre-compensation value to the reference signal via the second TRP. The UE adjusts its tracking loop for the reference signal based on the pre-compensation values, reducing estimation and/or search overhead at the UE.

Abstract: A network includes a first wireless node that communicates over a wireless network connection. The first wireless node includes a first encryption engine that processes a first initialization data set and a current transmit sequence associated with a current communication to generate a next transmit sequence that is employed to communicate with a second wireless node that derives a next received sequence that corresponds to the next transmit sequence to process a subsequent communication.

Abstract: A communication apparatus includes a coupler that is connected to a cable to which a first communication apparatus is connected, the first communication apparatus performing communication based on a wired communication scheme; communication circuitry that is connected to the coupler; and an antenna that is connected to the coupler, radiates a signal of the wired communication scheme to a second communication apparatus, and receives a signal of the wired communication scheme from the second communication apparatus. The coupler outputs, to the cable and the antenna, the signal of the wired communication scheme outputted from the communication circuitry, outputs, to the communication circuitry and the cable, the signal of the wired communication scheme received by the antenna, and outputs, to the communication circuitry and the antenna, the signal of the wired communication scheme received from the cable.

Abstract: A wireless power system has a wireless power transmitting device and a wireless power receiving device. The devices in the wireless power system may communicate using in-band communication. The wireless power transmitting device may transmit data to the wireless power receiving device using frequency-shift keying (FSK) modulation. The wireless power receiving device may transmit data to the wireless power transmitting device using amplitude-shift keying (ASK) modulation. While transmitting data to the wireless power receiving device using FSK modulation, the wireless power transmitting device may monitor for ASK modulation from the wireless power receiving device. In response to detecting the ASK modulation from the wireless power receiving device, the wireless power transmitting device may abort the FSK data transmission and process the detected ASK modulation to receive data from the wireless power receiving device.

Abstract: In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus at a UE in NTN are provided. The UE may be configured to receive one or more FPC commands from an NTN. The UE may be further configured to transmit, in response to receiving the one or more FPC commands, an uplink transmission with a frequency change having a total FPC adjustment calculated based on (a) a current UE location update and a current UE velocity update, wherein the total FPC adjustment satisfies one or more threshold requirements, or (b) an intermediary UE location update between the current UE location update and a previous UE location update and an intermediary UE velocity update between the current UE velocity update and a previous UE velocity update.

Abstract: The present document discloses a method for transmitting or receiving a signal by a terminal in a wireless communication system, the method comprising the steps of: receiving information relating to a timing advance (TA) and an uplink (UL) grant from a base station; transmitting a radio resource control (RRC) message to the base station on the basis of the TA and UL grant; and receiving downlink control information (DCI) on the basis of the RRC message, wherein the RRC message comprises information indicating whether the terminal supports a full-duplex radio (FDR) mode, and the DCI comprises an additional field indicating whether the FDR mode is allowed for the terminal.

Abstract: Some demonstrative embodiments include apparatuses, systems and/or methods of communicating a Single-User (SU) Multiple-Input-Multiple-Output (MIMO) transmission. For example, a first wireless communication station may be configured to transmit a Request to Send (RTS) to a second wireless communication station via a plurality of SU MIMO Transmit (Tx) sectors of the first wireless communication station, the RTS to establish a Transmit Opportunity (TXOP) to transmit an SU-MIMO transmission to the second wireless communication station, a control trailer of the RTS including an indication of an intent to transmit the SU-MIMO transmission to the second wireless communication station; and to transmit the SU-MIMO transmission to the second wireless communication station, upon receipt of a Clear to Send (CTS) from the second wireless communication station indicating that the second wireless communication station is ready to receive the SU-MIMO transmission.

Abstract: A method for predistortion comprising receiving a plurality of input signals forming a multiple-input signal in a multiple-input multiple-output system, generating a pre-distorted multiple-input signal from the received multiple-input signal, generating a multiple-output signal by feeding the pre-distorted multiple-input signal into a multiple-input and multiple-output transmitter, estimating impairments generated by the multiple-input and multiple-output transmitter, the impairments comprising nonlinear crosstalk between distinct ones of the plurality of input signals; and adjusting the pre-distorted multiple-input signal to compensate for the estimated impairments.

Abstract: A method for transmitting feedback information and a terminal device are provided. The method includes receiving, by a terminal device, trigger signaling. The trigger signaling is used for triggering the terminal device to send feedback information. The method further includes determining, by the terminal device, to send a first feedback information codebook or a second feedback information codebook according to the trigger signaling. The first feedback information codebook includes feedback information corresponding to at least one downlink channel indicated by the trigger signaling, and the second feedback information codebook is a full codebook.

Abstract: A frequency conversion beam squint correction method of an active phase array antenna system including a plurality (m) of beamforming units configured of an antenna, a first amplifier, a phase shifter, a variable attenuator, and a second amplifier, the method includes the steps of: adjusting a delay time of an applied RF signal by arranging m/2 true time delays (TTDs) for every two adjacent beamforming units; and converting the frequency of the RF signal by mixing the RF signal transferred to each of the m/2 true time delays and a local oscillation signal using a mixer.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit a monitoring signal associated with one or more antennas. The UE may identify, based at least in part on the monitoring signal, a blockage associated with the one or more antennas. The UE may perform a beam search using a decreased frequency of occurrence of tracking occasions for the one or more antennas based at least in part on the identification of the blockage associated with the one or more antennas. Numerous other aspects are provided.

Abstract: Certain aspects of the present disclosure provide techniques and apparatus for demapping a signal to a point in a signal constellation. An example method generally includes identifying a seed point in a signal constellation from a received signal. A candidate set of codes for the signal is generated based on a seed point and an additive perturbation applied to the seed point. A point in the signal constellation corresponding to the value of the received signal is identified based on a probability distribution generated over the candidate set of codes. Generally, the identified point corresponds to a code in the candidate set of codes having a highest probability in the probability distribution. The point in the signal constellation is output as the value of the received signal.

Abstract: A method and apparatus for performing uplink transmission and reception in a wireless communication system are disclosed.

Abstract: A precoding process is performed on a first baseband signal and a second baseband signal to generate a first precoding signal and a second precoding signal. A pilot signal is inserted into the first precoding signal and phase change is performed on the second precoding signal. A pilot signal is inserted into the phase changed second precoding signal, and phase change is further performed on the phase-changed second precoding signal with the pilot signal inserted.

Abstract: A method of a UE transmitting a codebook based uplink signal in a wireless communication system, the method comprising: transmitting capability information about UE capability that maintains differences between phase values applied to antenna ports for uplink signal transmission; receiving configuration information for determining a codebook subset related to the uplink signal transmission based on the capability information; receiving DCI for determining a precoding matrix applied to the uplink signal transmission; determining a precoding matrix to be applied for the uplink signal transmission, based on the DCI, from the codebook subset determined based on the configuration information: and transmitting the uplink signal, based on the determined precoding matrix, wherein, based on that the differences between phase values are maintained at some antenna ports, the codebook subset includes at least one specific precoding matrix applying different phase values to the antenna ports included in some or all of som

Abstract: A method performed by a base station in a wireless communication system, includes: determining, from among a plurality of antennas of the base station, a first antenna that meets a power threshold, based on a first beamformer scaled according to a power limit; generating a second beamformer corresponding to the first antenna; applying an overlap coefficient matrix to the second beamformer; generating a third beamformer by combining the second beamformer to which the overlap coefficient matrix has been applied and the first beamformer; and transmitting a signal using the third beamformer.

Abstract: Systems and methods for reporting channel state information. In some embodiments, the method includes: receiving, by a UE, a first Channel State Information Reference Signal (CSI-RS); receiving, by the UE, a second CSI-RS; calculating, by the UE, a first predicted channel state information based on the first CSI-RS and the second CSI-RS; and transmitting, to a network node (gNB), a first precoding matrix corresponding to the first predicted channel state information.

Abstract: A host configured to operate in a communication system to provide an over-the-top (OTT) service is described. The host initiates transmission of user data to a network node. In order to transmit the user data to a user equipment, the network node receives a channel state information (CSI) report for a downlink channel, the CSI report indicating a plurality of precoder vectors, wherein each of the precoder vectors corresponds to a frequency sub-band of a bandwidth of the downlink channel, each precoder vector being expressed as a linear combination of spatial-domain components and frequency-domain components. The network nodes determines precoding to use for transmitting data to the UE based at least in part on the CSI report. The network nodes transmits the user data from the host to the UE according to the determined precoding to provide the OTT service.

Abstract: In certain embodiments, a method performed by a wireless device comprises estimating a channel state of a downlink channel and transmitting a CSI report for the downlink channel based on the channel state. The CSI report indicates a plurality of precoder vectors, each corresponding to a frequency sub-band of the bandwidth of the downlink channel, a precoder vector being expressed as a linear combination of spatial-domain components and frequency-domain component wherein each of the spatial-domain components is associated with a respective set of one or more frequency-domain components.

Abstract: A method of managing wireless communication between electronic devices includes, at a first electronic device, transmitting a first downlink transmission from the first electronic device to a second electronic device and receiving a first response from the second electronic device at the first electronic device, wherein the first response includes a downlink channel quality information (CQI). The method further includes determining a per-subcarrier CQI based at least partially on the downlink CQI and determining an output modulation and coding scheme (MCS) based at least partially on the per-subcarrier CQI. After determining the output MCS, the method includes selecting a selected MCS based at least partially on the output MCS and setting an MCS of the first electronic device to the selected MCS.

Abstract: Disclosed are techniques for wireless positioning. In an aspect, a base station determines a channel profile for a multipath channel between the base station and a user equipment (UE) based on at least one positioning reference signal transmitted to the UE or received from the UE by the base station on one or more radio beams, compresses the channel profile into a compressed representation of the channel profile, and transmits the compressed representation of the channel profile to a network entity. The network entity receives the compressed representation of the time-angle channel profile and determines a location of the UE based on the compressed representation of the channel profile.

Abstract: A method for performing beamforming sounding feedback in a system-parameter-aware manner and associated apparatus are provided. The method applicable to a wireless transceiver device within a wireless communications system may include: checking a plurality of system parameters of the wireless communications system to generate a plurality of checking results of the plurality of system parameters, respectively, wherein any checking result among the plurality of checking results indicates a current value of a corresponding system parameter among the plurality of system parameters; modifying a first beamforming feedback matrix according to the plurality of checking results to generate a second beamforming feedback matrix; and sending beamforming sounding feedback information carrying the second beamforming feedback matrix to another device within the wireless communications system, for further processing of the other device.

Abstract: Systems and methods are provided to implement features in the IEEE 802. 11ad+/ay protocols by utilizing combinations of analog and digital precoding (such as hybrid mmWave precoding) to enable multi-stream/multi-user transmissions. These systems and methods are also suitable for 5G wireless networks, such as found in 3GPP. These systems and methods address performing general precoder design, reducing of beam-training overhead with leak wave antennas, performing single-stage approximate precoding with enhanced SLS for SU-MIMO transmissions (eSLS1), performing multi-stage approximate precoding with enhanced SLS for SU-MIMO transmissions (eSLS2), and performing exact precoding with enhanced SLS for SU-MIMO transmissions.

Abstract: A method of a terminal may comprise: receiving, from a base station, first unified transmission configuration indicator (TCI) information including a first TCI and a second TCI; receiving, from the base station, first downlink control information (DCI) including first scheduling information of a first physical downlink shared channel (PDSCH) and information indicating at least one TCI among the first TCI and the second TCI belonging to the first unified TCI information; and performing a first reception operation for the first PDSCH based on the at least one TCI and the first scheduling information.

Abstract: There are provided measures for enabling/realizing higher-layer beam management, e.g., beam failure detection or beam candidate detection in a higher layer such as a MAC entity. Such measures exemplarily comprise that a beam management timer is started when a (first) beam management instance indication from a lower layer is obtained, beam management is executed, wherein a beam management instance counter is incremented whenever a beam management instance indication from the lower layer is obtained and a beam management event is detected when the beam management instance counter reaches a beam management instance threshold before expiry of the beam management timer, and the beam management instance counter is reset upon expiry of the beam management timer.

Abstract: A method, system and apparatus are disclosed. According to some embodiments, a wireless device is provided. The wireless device includes processing circuitry configured to at least temporarily store at least one quasi co-located, QCL, property of at least one reference signal, RS, where the at least one RS is measured and reported while a previous Transmission Configuration Indicator (TCI) state is active, to allow for a TCI state update without having to wait for an occurrence of a reference signal associated with an updated TCI state, and apply a TCI state update based on the at least temporarily stored at least one QCL property of the at least one RS.

Abstract: A front end module (FEM) for a 5.6/6.6 GHz Wi-Fi acoustic wave resonator RF filter circuit. The device can include a power amplifier (PA), a 5.6/6.6 GHz resonator, and a diversity switch. The device can further include a low noise amplifier (LNA). The PA is electrically coupled to an input node and can be configured to a DC power detector or an RF power detector. The resonator can be configured between the PA and the diversity switch, or between the diversity switch and an antenna. The LNA may be configured to the diversity switch or be electrically isolated from the switch. Another 5.6/6.6 GHZ resonator may be configured between the diversity switch and the LNA. In a specific example, this device integrates a 5.6/6.6 GHz PA, a 5.6/6.6 GHZ bulk acoustic wave (BAW) RF filter, a single pole two throw (SP2T) switch, and a bypassable LNA into a single device.

Abstract: A spatial modulation system and a method for generating training sequences are provided. The method for generating training sequences includes: obtaining a cross Z-complementary set (CZCS); and obtaining a training sequence matrix according to cross Z-complementary sequences in the CZCS. Therefore, a larger zero correlation zone (ZCZ) width can be constructed, and the constructed sequence set has flexible lengths.

Abstract: A wireless repeater receives an RF signal at a first meta-surface antenna. A signal relay chain amplifies a received RF signal from the first meta-surface antenna into a transmit RF signal that is transmitted by a second meta-surface antenna. Alternatively, the signal relay chain receives the RF signal at a reception port of the first meta-surface antenna, which may include a transmit port for receiving the transmit RF signal.

Abstract: A repeater system includes a first repeater device that receives a first beam of radio frequency (RF) signal from a first network node and a second repeater device that receives a second beam of RF signal from the first network node. The first repeater device controls the second repeater device to provide the first beam of RF signal and the second beam of RF signal to a second network node and select a plurality of signal parameters at the first repeater device and the second repeater device for the first beam of RF signal and the second beam of RF signal respectively, based on a plurality of measurements. The first repeater device further controls the second repeater device to establish an additional link with the second repeater device to create an additional dimension in a MIMO channel between the first network node and the second network node.

Abstract: The invention provides a method for configuring a mobile relay node in a communications system wherein the method comprises the mobile relay node requesting location dependent configuration data from an infrastructure node of the communications system; the mobile relay station receiving from the infrastructure node said location dependent configuration data; and configuring radio transmission characteristics of the mobile relay node in accordance with the received location dependent configuration data.

Abstract: Disclosed herein are system, method, and computer program product embodiments for utilizing parallel links to improve sub-network availability and latency performance for ATC traffic. An embodiment operates by receiving a generated message. The type of the generated message is determined, where the type is an air traffic control message or a non-air traffic control message. Based on the type of message, communication links are selected, where the communication links include parallel transmission links or a serial link. The method continues by copying the generated message and transmitting the copied message using the selected communication links. The method waits to receive an acknowledgement indicating receipt of the transmitted message. Upon identifying an acknowledgement, any of the copied messages not yet retransmitted are deleted.

Abstract: The present disclosure relates to a 5th generation (5G) or 6th generation (6G) communication system for supporting a data rate higher than a 4th generation (4G) communication system such as long term evolution (LTE). The present disclosure provides a satellite communication cell management apparatus for managing satellite communication cells of at least one satellite, the satellite communication cell management apparatus including a transceiver, and at least one processor, wherein the at least one processor is configured to connect the satellite communication cells to base stations (BSs), and update connections between the satellite communication cells and the BSs, according to a relative movement of the at least one satellite with respect to the ground.

Abstract: Systems and methods for controlling satellites are provided. In one example embodiment, a computing system can obtain a request for image data. The request can be associated with a priority for acquiring the image data. The computing system can determine an availability of a plurality of satellites to acquire the image data based at least in part on the request. The computing system can select from among a plurality of communication pathways to transmit an image acquisition command to a satellite based at least in part on the request priority. The plurality of communication pathways can include a communication pathway via which the image acquisition command is indirectly communicated to the satellite via a geostationary satellite. The computing system can send the image acquisition command to the selected satellite via the selected communication pathway.

Abstract: A method and an apparatus for network synchronization in a satellite communication system is provided. a satellite station receives a superframe start timing (SST) and an initial counter value from a center station, and receives traffic information sent from a terminal station at a time determined based on the SST. Then, the satellite station generates a compensation value for the SST upon receiving the traffic information, and corrects the SST in accordance with the compensation value.

Abstract: Provided is a multiplex transmission system capable of realizing a redundant configuration for coping with a failure while reducing useless resources. A multiplex transmission system includes: a resource pool 130 which is provided in a first multiplex transmission apparatus 100 and which has resources capable of selectively constructing one or more functions among a plurality of functions; a monitoring unit which monitors, when a failure occurs, information on the failure; and a control unit which controls the resource pool. The control unit causes, when a failure occurs, the resource pool 130 to execute construction of a function necessary for constructing a redundant configuration according to contents of the failure on the basis of a monitoring result by the monitoring unit.

Abstract: A method for monitoring a distributed antenna system includes: at a relay device, receiving a first operation monitoring signal sent by the near-end device, where the first operation monitoring signal carries an operation monitoring message, and the operation monitoring message includes a device address of a monitoring target device; determining whether to analyze the first operation monitoring signal according to a connection status with the near-end device; in response to a determination to analyze the first operation monitoring message signal, analyzing the first operation monitoring signal to confirm the monitoring target device and to determine whether to respond to the operation monitoring message; and in response to a determination to respond to the operation monitoring message, responding to the operation monitoring message according to the monitoring target device as confirmed.

Abstract: A host module configured for insertion into a chassis of a network element includes a Printed Circuit Board (PCB); a plurality of rails disposed on the PCB, for housing one or more universal sub slot modules on the host module, wherein the plurality of rails are for guiding a universal sub slot module during insertion and for stabilization thereof; and a faceplate disposed to the PCB and including one or more openings each for the one or more universal sub slot modules, wherein the PCB communicates to each of the one or more universal sub slot modules via a plurality of high-speed links that are at least 28 Gbps each. At least one of the one or more universal sub slot modules can be a coherent modem or a router.

Abstract: A transmitter for an optical communication network includes a primary laser source input substantially confined to a single longitudinal mode, an input data stream, and a modulator including at least one secondary laser having a resonator frequency of the single longitudinal mode of the primary laser source. The modulator is configured to receive the primary laser source input and the input data stream, and output a laser modulated data stream.

Abstract: An optical module includes a plurality of lasers, each of at least some of the lasers configured to be selectively turned on and turned off depending on a type of modulation to be used. Each laser corresponds to a respective wavelength. The optical module also includes an optical modulation system having a plurality of optical modulators. A reconfigurable optical network of the optical module is configured to selectively direct light from the plurality of lasers to the optical modulation system differently depending on the type of modulation to be used.

Abstract: In the present invention, in order to enable stable operation of a single-wave-modulation transmission device, etc., for a longer period, a processing device comprises: a processing unit for performing an adjustment process, which is a process in which the intensity and wavelength of a laser beam from a semiconductor laser used for transmission is adjusted on the basis of the intensity of the laser beam that has not passed through a wavelength filter that restricts the wavelength band of the laser beam and the intensity of a laser beam that has passed through the wavelength filter; and a storage unit for storing the result of the adjustment process.

Abstract: An optical signal transmission method according to an embodiment of the disclosure is an optical signal transmission method in which a processor performs at least part of each operation, and may include an operation of receiving a data stream, an operation of separating at least part of the data stream into three channels, modulating the separated data streams respectively according to M-ary frequency shift keying (M-FSK) scheme so as to produce an FSK modulated signal, an operation of combining a plurality of FSK modulated signals modulated respectively in the three channels, and producing a color modulated signal according to a bit-color mapping table set in advance, and an operation of transmitting the color modulated signal by controlling a light source of the same optical channel based on the color modulated signal.