Abstract: The present invention relates to a circuit assembly which comprises an antenna path (A1), which can be connected to a first antenna (ANT1), a transmission path (TX1), a reception path (RX1), a duplexer (DPX1), operating with acoustic waves, which connects the transmission and reception paths (TX1, RX1) in each case to the antenna path (A1), and means for suppressing an interference signal.

Abstract: Apparatus and methods for radio frequency (RF) switches are provided herein. In certain implementations, an RF switching circuit includes an adaptive switch bias circuit that controls gate and/or channel voltages of one or more field effect transistor (FET) switches. Additionally, the adaptive switch bias circuit is powered by a power high supply voltage and a power low supply voltage, and can be used to selectively turn on or off the FET switches based on a state of one or more switch enable signals. The adaptive switch bias circuit adaptively biases that gate and/or channel voltages of the FET switches based on a voltage difference between the power high and power low supply voltages to provide switch biasing suitable for use with two or more different power supply voltage levels.

Abstract: Methods and devices are described for overcoming insertion loss notches in RF systems. In one case programmable impedances are used to move an insertion loss notch outside a frequency band of interest.

Abstract: An antenna arrangement includes a switch having an open state and a closed state, a first antenna that operates as a first active driven element in a first frequency band in response to the switch being in the open state, and a second antenna that operates as a second active driven element in a first frequency band in response to the switch being in the open state. The closed state configures the first antenna and the second antenna to operate in a second frequency band different from the first frequency band by operatively coupling a first impedance between the first antenna and a radio frequency ground, and by operatively coupling a second impedance between the second antenna and the radio frequency ground. The first antenna functions as a parasitic element in the second frequency band and the second antenna functions as an active driven element in the second frequency band.

Abstract: An apparatus comprises a tunable duplexer configured to output a transmission signal to be wirelessly transmitted from the apparatus at a transmission frequency, and configured to input a reception signal wirelessly received by the apparatus at a reception frequency, a tuning device connected to the tunable duplexer, configured to control a balance between impedances of an antenna port and of a balance port of the tunable duplexer, a transmitting device configured to, during a predetermined time period, wirelessly transmit a specific transmission signal for calibration of the tunable duplexer, a receiving device configured to, during the predetermined time period, wirelessly receive the specific transmission signal transmitted by the transmitting device, and a measuring device configured to, during the predetermined time period, measure the power of the specific transmission signal received by the receiving device.

Abstract: Provided is an encoding/decoding apparatus and method of multi-channel signals. The encoding apparatus and method of multi-channel signals may encode phase information of the multi-channel signals using a quantization scheme and a lossless encoding scheme, and the decoding apparatus and method of multi-channel signals may decode the phase information using an inverse-quantization scheme and a lossless decoding scheme.

Abstract: A sequence allocating method and apparatus wherein in a system where a plurality of different Zadoff-Chu sequences or GCL sequences are allocated to a single cell, the arithmetic amount and circuit scale of a correlating circuit at a receiving end can be reduced. In ST201, a counter (a) and a number (p) of current sequence allocations are initialized, and in ST202, it is determined whether the number (p) of current sequence allocations is coincident with a number (K) of allocations to one cell. In ST203, it is determined whether the number (K) of allocations to the one cell is odd or even. If K is even, in ST204-ST206, sequence numbers (r=a and r=N?a), which are not currently allocated, are combined and then allocated. If K is odd, in ST207-ST212, for sequences that cannot be paired, one of sequence numbers (r=a and r=N?a), which are not currently allocated, is allocated.

Abstract: A method and apparatus are provided for providing improved spectrum efficiency by triggering a ranked transmission. In this regard, a method is provided that includes causing a configuration message to be transmitted to a mobile terminal, wherein the configuration message provides interpretation information for a frequency hopping flag bit. The method also includes determining a rank for a transmission. The method may include setting a rank indication in the frequency hopping flag bit of a downlink control message based on the determined rank of the transmission.

Abstract: Techniques for performing frequency hopping in a wireless network are described. In an aspect, frequency hopping may be performed based on both cell identity (ID) and system time information. In one design, a user equipment (UE) may determine a cell ID of a cell and may obtain system time information for the cell. The UE may determine resources to use for transmission with frequency hopping based on the cell ID and the system time information. In one design, the UE may initialize a PN generator in each radio frame with an initial value determined based on the cell ID and a system frame number (SFN) for the radio frame. The UE may determine the resources to use for transmission based on a hopping function, a mirroring function, and a PN sequence from the PN generator. The UE may send a transmission on the resources to the cell.

Abstract: A DSL transmitter and receiver are disclosed that are capable of accurately measuring crosstalk in G.vector-compliant DSL lines resulting from a legacy line. During crosstalk measurement, the legacy line can be placed in a showtime mode. Once in showtime mode, a data signal designated for the legacy line is reduced in power spectrum density and/or spectrum to reduce its effects on crosstalk measurements. An O-P-Vector-1 signal is then superposed on the reduced data signal, and the resulting test signal is transmitted over the legacy line while sync signals are transmitted over neighboring G.vector lines. The receiver can then accurately measure the crosstalk on the neighboring lines, and report back to the transceiver for adjustments. A similar configuration can be performed in a diagnostic mode of the legacy line.

Abstract: In a vectoring-capable DSL system, power can be saved by a low power mode wherein data transmission is reduced or halted, but synch symbols continue to be transmitted, so that estimation of crosstalk coefficients may continue during the low power mode. When crosstalk coefficient estimates are up to date, a line may exit low power mode without causing problematic changes of crosstalk noise in other lines, since the vectoring functionality will eliminate or reduce the crosstalk.

Abstract: Aspects disclosed herein relate to improving technology detection and collision resolution among multiple NFC devices using a NFC type-A RF technology. In one example, a communications device is equipped to determine that a first device sensing response message includes one or more collisions, identify a first remote NFC device of the plurality of remote NFC devices by performing collision resolution on the first device sensing response message, transmit a sleep request message to the first remote NFC device that prohibits the first remote NFC device from responding to a first device sensing request message and the first device sensing request message, receive a second device sensing response message that includes collisions among the plurality of remote NFC devices, and identify a second remote NFC device of the plurality of remote NFC devices by performing collision resolution on the second device sensing response message.

Abstract: Method and apparatus for alerting a user to presence within a vehicle of an item having an active near-field communication device (NFCD) associated therewith, such as a smartphone. A passive NFCD is located adjacent to a storage compartment within a vehicle. When the active NFCD-equipped item is placed in the compartment, communication is established between the active and passive NFCDs. A controller device is communicatively connected to the vehicle to detect a journey completion event and send a wireless message (via Bluetooth, for example) to the item. The message instructs the item to output an alert if the active and passive NFCDs are in communication with one another. Journey completion events may be turning off of a vehicle ignition, opening of a vehicle door, or a vehicle seat becoming unoccupied.

Abstract: An approach is provided for retrieving ordered content via a service endpoint. A radio frequency memory tag is preloaded with content managed by a service platform. A request is generated for content stored on the radio frequency memory tag of an endpoint associated with the service platform. Transmission of the request to the endpoint is initiated. The request for the content is received from a user equipment. Transmission of the content is initiated from the memory tag to the user equipment. The user equipment receives the content from the memory tag in response to the request.

Abstract: A communication partner appliance is implemented within a near field communication system. The communication partner appliance includes a receiver, a detector, and a processor. The receiver receives a NFC command signal from another communication partner appliance. The detector detects whether a carrier signal from the other communication partner appliance is present at the receiver at a time other than during a transmission of the NFC command signal from the other communication partner appliance to the receiver. The processor controls a power supply element based on a determination by the detector whether the carrier signal from the other communication partner appliance is present at the receiver. The power supply element is configured to establish a connection to either a first power supply or a second power supply. The first power supply is dependent on the carrier signal, and the second power supply is independent of the carrier signal.

Abstract: Embodiments of the present invention provide a downlink precoding method and data interacting method for coordinated multi-point transmission system and apparatus. The downlink precoding method includes: acquiring a precoding matrix indicator by a cooperating point and determining the precoding matrix of the cooperating point according to the precoding matrix indicator, the number of columns of the precoding matrix of the cooperating point being less than that of columns of the precoding matrix of a serving point; and performing, by the cooperating point, downlink precoding to the data to be transmitted according to the determined precoding matrix of the cooperating point. With the methods and apparatuses of the embodiments of the present invention, as the cooperating points participate only in the transmission of data of part of layers in the coordinated scenarios, the complexity of calculation and the feedback overhead are lowered in the UE end.

Abstract: A MIMO radio transceiver to support processing of multiple signals for simultaneous transmission via corresponding ones of a plurality of antennas and to support receive processing of multiple signals detected by corresponding ones of the plurality of antennas. The radio transceiver provides, on a single semiconductor integrated circuit, a receiver circuit or path for each of a plurality of antennas and a transmit circuit or path for each of the plurality of antennas. Each receiver circuit downconverts the RF signal detected by its associated antenna to a baseband signal. Similarly, each transmit path upconverts a baseband signal to be transmitted by an assigned antenna.

Abstract: A method of selecting antenna segments for transmission and/or reception in a MIMO wireless transmission system using sectorized directional antennas, includes the steps of selecting, from an initial set of ranked link antenna patterns, a link antenna pattern having the best average rank, at predetermined time intervals, successively selecting a subset of link antenna patterns having average ranks within a predetermined distance to the best average rank, determining an average link performance of the link antenna patterns selected in the preceding step, determining an average rank of the link antenna patterns, for which the average link performance has been determined in the preceding step, selecting the link antenna pattern having the best average rank, and repeating the process at the next predetermined time interval.

Abstract: A signal generation method is used in a transmission device that transmits a plurality of transmission signals from a plurality of antennas at the same frequency and at the same time, in the case where larger power change is performed on a first transmission signal than on a second transmission signal during generation process of the first transmission signal and the second transmission signal, the first transmission signal and the second transmission signal are mapped before the power change such that a minimum Euclidian distance between possible signal points for the first signal is longer than a minimum Euclidian distance between possible signal points for the second signal.

Abstract: To perform wireless communications in a closed loop multiple input, multiple output (MIMO) system, a feedback data structure is communicated over a wireless channel between a first wireless node and a second wireless node, where the feedback data structure contains indicators identifying coding to be applied by the second wireless node on signaling communicated between the second wireless node and the first wireless node, where the information in the feedback data structure is based on wireless channel conditions detected at the first wireless node. The indicators identify different codings to be used for different corresponding bands in the wireless channel.

Abstract: Techniques are described for carrier frequency offset (CFO) and channel estimation of orthogonal frequency division multiplexing (OFDM) transmissions over multiple-input multiple-output (MIMO) frequency-selective fading channels. A wireless transmitter forms blocks of symbols by inserting training symbols within two or more blocks of information-bearing symbols. The transmitter applies a hopping code to each of the blocks of symbols to insert a null subcarrier at a different position within each of the blocks of symbols, and a modulator outputs a wireless signal in accordance with the blocks of symbols. A receiver receives the wireless signal and estimates the CFO, and outputs a stream of estimated symbols based on the estimated CFO.

Abstract: The present invention relates to a wireless communication system, and more specifically, disclosed are a method and an apparatus for virtualizing an antenna. A method for communicating using a virtual antenna of a terminal in the wireless communication system, according to one embodiment of the present invention, comprises the steps of: configuring one or more virtual antennas according to an antenna virtualization pattern that is determined based on information indicating a movement status of the terminal and/or information indicating a communication status of the terminal; and communicating with the base station by using the one or more virtual antennas, wherein one or more physical antennas that are mapped to the one or more virtual antennas can be determined base on the direction of movement of the terminal.

Abstract: A beam-forming network for an emitting array antenna having at least NB input ports connected to respective beam ports of the beam-forming network and at least NOSA>1 output ports, for associating to each output port a linear combination of input signals from respective input ports; a set of at least NOSA lossless single-mode networks, each having an input port connected to a respective output port of multi-beam network and at least NNOSAOSA>1 output ports, for associating to each output port a signal obtained by weighting an input signal from the input port; and a set of at least NNOSA?NNOSAOSA lossless multi-mode networks, each having at least NNOSAOSA NOSANOSA input ports, each one connected to an output port of a respective single-mode network, and at least NENOSA>1 output ports connected to respective antenna ports of the beam-forming network, for associating to each output port a linear combination of input signals from respective input ports.

Abstract: A method and apparatus may be used in Very High Throughput (VHT) Wireless Local Area Network (WLAN) management actions. Management action frames such as VHT Action frames may be used to implement VHT features in WLANs. Extensions to 802.11 Action frames may be used to support VHT features and provide backward compatibility. VHT Management Actions may be supported with VHT Action frames and VHT extensions to 802.11 Action frames in various categories such as Direct Link Setup (DLS), Public, Spectrum Management and high throughput (HT). An access point (AP) or a wireless transmit/receive unit (WTRU) may indicate VHT capability by way of signaling.

Abstract: In a base station, a downlink radio resource and an uplink radio resource to be used for transmission of a known signal from a communication terminal are associated for null steering to be performed based on the known signal. A correction value calculating unit calculates a first correction value used to correct a downlink quality value obtained by a communication terminal. The correction value calculating unit calculates a second correction value used to correct a downlink quality value obtained by a communication terminal.

Abstract: A method of wireless communication includes communicating in a plurality of subframes. The subframes include a first type of subframe and a second type of subframe. The method further includes utilizing a transmission mode for each of the subframes based on the type of each of the subframes. A second method of wireless communication includes communicating in a plurality of subframes. The subframes include a first type of subframe and a second type of subframe. The second method further includes configuring a UE with a transmission mode for each of the subframes based on the type of each of the subframes.

Abstract: First and second transmission channel correction circuits generate a corrected data signal and a corrected control signal by executing a transmission channel correction to a data signal transmitted by a first modulation method and a control signal transmitted by a second modulation method that is more tolerant to noise than the first modulation method. The data signal and control signal are included in reception signals received by first and second antennas. First and second quality information calculation circuits calculate quality information indicating quality of the reception signal on the basis of the corrected control signal. A combination ratio calculation circuit calculates a combination ratio of the corrected data signals generated by the first and second transmission channel correction circuits, on the basis of two types of quality information calculated by the first and second quality information calculation circuits. A combination circuit executes combination at the combination ratio.

Abstract: An apparatus including at least one processor and at least one memory including computer program code the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: determining for a group of symbols at least one candidate transmission symbol position, wherein the group of symbols include a first symbol position part for backhaul downlink symbol positions and a second symbol position part including the at least one candidate transmission symbol position; and generating at least one further backhaul downlink symbol for the at least one candidate transmission symbol position.

Abstract: Generally discussed herein are systems, apparatuses, and methods that can provide a coverage enhancement to a coverage limited device. According to an example a method can include repeating a Physical Broadcast Channel (PBCH) data transmission multiple times over multiple sub-frames to a coverage limited Machine Type Communication (MTC) User Equipment (UE), or repeating the PBCH data transmission two or three times within one sub-frame to the coverage limited MTC UE.

Abstract: A satellite-based communication system (1) comprises a router system (6) which receives from a switching unit (3) via a satellite system (4) network addressing information associated with communication terminals (2) connected to the switching unit (3). The network addressing information of the communication terminals (2) are stored in the router system (6) assigned to telephone numbers associated with the communication terminals (2). For enabling an exchange unit (7) to route via the satellite link (40) received data to the communication terminal (2), the router system (6) transmits to the exchange unit (7) the network addressing information associated with the communication terminals (2) connected to the switching unit (3). Hence, data can be routed flexibly in the satellite-based communication system (1) between communication terminals (2, 2?) which are not configured for satellite communication and which are used by mobile users who may move in areas covered by different satellites (43).

Abstract: Methods and apparatus for providing primary transport service discovery information over one or more alternate transports that are not normally associated with the primary transport services. In one embodiment, the primary transport comprises a first wireless interface (e.g., Bluetooth), and the alternate transport comprises a second wireless interface (e.g., WiFi or WiMAX). Service profile information relating to the primary transport is broadcast to other users over the alternate transport in a more efficient and streamlined manner than that available on the primary transport. The other users store this service profile information so that it can be subsequently accessed for service profile discovery of the transmitting device by those other devices, thereby obviating subsequent transfer of the data over any transport (primary or alternate).

Abstract: Circuit connectors for establishing EHF communication include a receiver configured to receive a transmitted EHF electromagnetic signal, and an output circuit coupled to the receiver. The output circuit has two states of operation that correspond to enabling a signal output and disabling the signal output. The output circuit is also configured to change its state of operation responsive to a state of a control signal, and a controller is coupled to the receiver and configured to produce the control signal. The control signal has two states that correspond to a first condition when the received signal exceeds a first threshold and a second condition when the received signal is less than a second threshold.

Abstract: An apparatus for reducing TDMA noise in a terminal transceiving a wireless signal in a TDMA scheme, includes an interface unit in which an output accessory is mounted, an audio processor including a virtual ground and transceiving an audio signal to and from an output accessory through the interface unit, a switch unit provided between the interface unit and the audio processor and switching such that a ground terminal of the interface unit is connected to one of a real ground or a virtual ground of the audio processor, and a controller controlling the switch unit to connect the ground terminal of the interface unit to the virtual ground when a call function using the output accessory is activated, in which the switch unit is configured by two or more switches which are connected to each other in a parallel connection.

Abstract: A transmitting apparatus, a receiving apparatus, and a communication system are provided that allow a reduction in a frame loss due to interference caused by use of the same channel. A transmitting apparatus disposed in a base station includes a GPS receiver for receiving a GPS signal, a timing generator for controlling respective function blocks in accordance with the GPS signal and an inter-base-station control signal so as to precisely synchronize the timing of frame transmission among base stations, the front-end transmission processing unit including for converting transmission information into transmission time slots, a frame generator for generating a frame including a plurality of time slots and one frame guard, and a back-end transmission processing unit for transmitting the generated frame as a radio signal.

Abstract: A method is provided for detecting movement indicative of intrusion events on optical drop fibers of a network where the individual drop fiber can be identified to locate the event. The method uses a monitor system at the network end and multiplexing the monitor signal along the individual fibers to the respective terminals. At each of the terminals, the monitor signal is returned unchanged or in modified form along the same or different fibers to the network end. At the network end the received monitor signals is analyzed for changes in said monitor signals indicative of movement. Which one or more of the drop fibers has triggered the alarm is determined by modifying the monitor signal in wavelength or polarization, or by applying a modulation at the source and/or at multiplexing and/or at returning so that the monitor signal of one drop fiber has a difference from the monitor signal of another drop fiber.

Abstract: Systems and methods of electronic wavefront correction are disclosed. An example method receiving an optical signal representing a wavefront traveling along a plurality of propagation paths, and electronically correcting distortion in the wavefront. An example apparatus includes an receiver and an electronic wavefront corrector. The receiver is configured to coherently receive an optical signal representing a wavefront traveling along a plurality of propagation paths. The electronic wavefront corrector is configured to correct phase distortion in the wavefront.

Abstract: A reception display apparatus and the like which display display information regarding an information transmission apparatus blocked by an obstacle, on an image representing a taken video image, such that the display information corresponds to the position of the information transmission apparatus, are provided. A reception section time-sequentially takes an image and receives, from an apparatus, direct-transmission information including information regarding the apparatus, and forwarding information which includes information regarding an apparatus and relative position information indicating a relative position of the apparatus with respect to the apparatus. A measurement section measures a relative position of the apparatus with respect to the own apparatus.

Abstract: A method of registering a wireless device located in premises in a wireless network which is constructed in the premises. The method includes receiving a light signal, which includes network identification information of the wireless network constructed in the premises from at least one illumination device installed in the premises, and registering the wireless device in the wireless network constructed in the premises, by using the network identification information of the wireless network included in the received light signal.

Abstract: A method of optimizing a link budget analysis comprising performing a first LBA based on a target modulation and coding pair (MODCOD), the MODCOD having a symbol energy to noise density ratio (Es/No), a target setting of a power amplifier, or a target antenna size, determining an excess margin and increasing or decreasing a maximum available MODCOD accordingly, iteratively performing a second LBA, calculating a ratio of allocated bandwidth to PEB and adjusting at least one of the MODCOD, amplifier power, and antenna size, summing a contribution to a final ratio of allocated bandwidth to PEB of the plurality of communications links, accessing a look up table and selecting a new MODCOD or adjusting the amplifier size or antenna size is based on the ratio of allocated bandwidth to PEB and altering one or more transmission or receiving parameters to apply the optimal MODCOD, amplifier size, or antenna size.

Abstract: Described herein are technologies related to a semiconductor package that is installed in a portable device for data communications. More particularly, the semiconductor package that contains a memory, a digital logic chip, and an optical port in a single module or mold is described.

Abstract: An optical waveguide substrate includes: a substrate body in which an optical waveguide is formed; a cable holding part configured to have a cable holding hole into which a signal cable is inserted, the signal cable having one of an incidence part and an emission part that is arranged so as to face the optical waveguide and having a first magnetic part; and a second magnetic part configured to generate a repulsive force in the cable holding hole in association with the first magnetic part.

Abstract: An optical access system is provided that enables subscriber terminals or termination devices to be interconnected via dedicated lines as needed, with respect to subscriber terminals or termination devices participating in an optical network. The optical network is a network connecting a plurality of accommodating stations, and in this network, the accommodating stations have a plurality of optical line termination devices and optical path selection means, the subscriber side optical terminals or optical line termination devices are connected in single star optical paths, and the optical line termination devices in the accommodating stations are connected with the above mentioned optical terminals or optical line termination devices via the optical path selection means.

Abstract: An interconnect system includes a first circuit board, first and second connectors connected to the first circuit board, and a transceiver including an optical engine and arranged to receive and transmit electrical and optical signals through a cable, to convert optical signals received from the cable into electrical signals, and to convert electrical signals received from the first connector into optical signals to be transmitted through the cable. The transceiver is arranged to mate with the first and second connectors so that at least some converted electrical signals are transmitted to the first connector and so that at least some electrical signals received from the cable are transmitted to the second connector.

Abstract: A fiber optic system includes a transmitter configured to utilize a plurality of modulation formats and a receiver communicatively coupled to the transmitter and configured to utilize a plurality of modulation formats. The transmitter and the receiver are cooperatively configured to set a modulation format of the plurality of modulation formats based upon optical signal-to-noise ratio associated therewith. A flexible bandwidth adaptation method includes monitoring at least one aspect of an optical link at a network element, responsive to the at least one aspect, computing a new modulation scheme for the optical link, and, if a solution is found for the new modulation scheme, changing to the new modulation format.

Abstract: An apparatus includes an optical transmitter configured to provide an optical signal amplitude-modulated among M different levels. A constellation control module is configured to provide a drive signal to control the optical signal. A feedback module is configured to receive a measure of spacing between amplitude peaks of a symbol constellation of the optical signal. The feedback module is further configured to regulate the constellation control module to adjust the optical signal in response to the measure of spacing.

Abstract: A system of thermally tuning an optical device is described. The system may include an optical device configured to output an optical signal. An amplitude of the optical signal may be dependent on a temperature of the optical device. The system may also include a control circuit, an adjust circuit, and a heater circuit. The control circuit may be configured to output a control current. The adjust circuit may be configured to perform an approximate square-root operation on the control current and to output a modified control current. The heater circuit may be coupled to the adjust circuit and may be configured to generate heat based on the modified control current. The heater circuit may also be positioned such that the generated heat affects the amplitude of the optical signal. The control circuit may linearly adjust the control current to approximately linearly adjust the heat generated by the heater.

Abstract: An optical communication fiber includes: a fiber body having a tip surface; and a light absorption layer provided to the tip surface of the fiber body, and configured to reduce light transmittance of communication light.

Abstract: An optical receiving device includes: an adaptive equalizer that includes a position estimation unit configured to estimate, based on a first signal component and a second signal component of a reception signal generated by reception of a training sequence pattern transmitted from an optical transmitter, a symbol position of the reception signal, and generates an estimated symbol position, a delay unit configured to provide a delay difference between the first signal component and the second signal component, a control unit configured to set a plurality of symbol displacement amount candidates of displacement amounts for the estimated symbol position, causes the delay unit to generate a plurality of delay differences, and generates a channel estimation symbol position used for channel estimation, and an error rate calculation unit configured to calculate an error rate of the signal restored by an adaptive equalization unit.

Abstract: Disclosed herein is an optical transport system configured to transport an amplitude-modulated optical signal generated at the transmitter using single-sideband modulation of an optical carrier and detected at the receiver using direct optical detection. The receiver is configured to estimate the level of signal-signal beat interference (SSBI) in the electrical signal generated upon direct detection of the received optical signal by first converting this electrical signal into a modified baseband signal configured for single-sideband modulation and then squaring and appropriately scaling this modified baseband signal. The receiver is further configured to subtract the estimated level of SSBI from the electrical signal generated by the direct optical detector and to process the resulting corrected electrical signal to recover the data encoded in the amplitude-modulated optical signal. Example analog and digital circuits for estimating the level of SSBI at the receiver are disclosed.

Abstract: In the optical receiver available for the RZ-DPSK modulation system, the difference in the received intensity due to the difference in the intensity or optical path of the optical signal cannot be corrected automatically, therefore, an optical receiver according to an exemplary aspect of the invention includes a first photodiode receiving a normal phase optical signal from a first output of a 1-bit delayed interferometer and outputting a positive signal; a second photodiode receiving a reversed phase optical signal from a second output of the 1-bit delayed interferometer and outputting a complementary signal; a differential transimpedance amplifier inputting the positive signal and the complementary signal and including a closed feedback loop for each input of the positive signal and the complementary signal; a level adjustment unit adjusting a signal level in the closed feedback loop; a photoelectric current detection unit detecting a photoelectric current generated in each of the first photodiode and the se