Abstract: An apparatus of automatic power control for burst mode laser transmitter and method are provided. In one implementation a method includes: pushing a first multi-bit data into a data memory; modifying the data memory to remove a condition of frequent transition in the data memory, if the condition of frequent transition is found; establishing a list of indices pointing to data transition of the data memory; and sequentially examining a respective run length of the data indexed by each entry in the list, modifying the associated data to lengthen the respective run length if the respective run length is too short, modifying the associated data to shorten the respective run length if the respective run length is too long, and outputting a second multi-bit data by taking data from the data memory.

Abstract: A method of equalizing signals from a plurality of balanced transmission line cables having different lengths includes providing a first cable having a first length and a second cable having a second length, the first cable coupled to a variable resistor. A first signal is transmitted along the first cable to the variable resistor such that the first signal is attenuated to assume a first frequency domain characteristic. A second signal is transmitted along the second cable such that the second signal is attenuated to assume a second frequency domain characteristic. A voltage of the first signal is divided in the variable resistor such that the first signal assumes substantially the second frequency domain characteristic. The first signal having the second frequency domain characteristic is outputted.

Abstract: A multiple antenna system including a mobile station and a base station are operable to perform a method for transmitting control information for interference mitigation. A Mobile Station (MS) can transmit control information for interference mitigation. The MS determines a first Precoding Matrix Index (PMI) and a second PMI for interference from an adjacent Base Station (BS). Based on a correlation level from correlation values between one of the first PMI and second PMI and the remaining PMIs in the codebook, the MS determines a level of a subset of PMIs, and feeds back information indicating the correlation level.

Abstract: A system and methods for estimating a noise power level in an uplink signal for a virtual MIMO system is disclosed. The system comprises a demodulation reference signal (DMRS) module configured to obtain a DMRS receive symbol from the uplink signal and determine a DMRS sequence for a first UE in the virtual MIMO system. An autocorrelation module is configured to calculate an average autocorrelation value for the subcarriers in the uplink signal. A cross-correlation module is configured to calculate first and second cross-correlation values of the uplink signal RZ(l) for values of l selected such that the sum of the received power from the first UE and the second UE can be accurately estimated. A noise power level module is configured to determine the noise power level for the uplink signal using the average autocorrelation value and the first and second cross correlation values.

Abstract: A communications system includes a receiver unit connected with a transmission channel. The receiver unit determines a signal power of a first communications signal received over the transmission channel. A transmitter unit is connected with the transmission channel and transmits a second communications signal, wherein a gain of the communications signal being output by the transmitter unit is controllable. A control unit controls the gain of the transmitter unit in response to the determined signal power. At the receiver unit, detection of broadcast signal ingress during data communication is improved and methods for avoiding disturbances between coexisting communications systems may become more reliable. Different distances between successive training symbols suitable for channel estimation may be provided to enhance the noise measurement.

Abstract: Circuits, architectures, methods, algorithms, software, and systems for increasing reliability of data communications using time diversity coding are disclosed. An association circuit is configured to associate a first reliability factor with a first copy of the communicated data and a second reliability factor with a second copy of the communicated data, wherein the first reliability factor is different from the second reliability factor and has a value that is a predetermined function of a known characteristic of the data communications channel at a time that the communicated data passed through the channel. A decoder is configured to recover a reliable value for the communicated data from the first copy, second copy, first reliability factor, and second reliability factor.

Abstract: A receiver includes a first receiver chain configured to receive a first input signal and a second receiver chain configured to receive a second input signal. A first phase predistorter is provided in the first receiver chain and is configured to shift a phase of the first input signal by a first phase shift ??A(f). A combiner is coupled to the first receiver chain and the second receiver chain and combines the first and second input signals. The first phase shift is selected to cause undesired signal components received in the first and second input signals to combine destructively.

Abstract: A received plurality of signals may be filtered to select an in-band signal and/or an out-of-band. A signal strength of the selected signal(s) may be measured. A resolution of an analog-to-digital converter may be controlled based on the measured signal strength(s). The selected in-band signal may be converted to a digital representation via the analog-to-digital converter. The resolution may be decreased when the strength of the in-band signal is higher, and increased when the strength of the in-band signal is lower. The resolution may be increased when the strength of the out-of-band signal is higher, and decreased when the strength of the out-of-band signal is lower. A signal-to-noise ratio and/or dynamic range of the selected signal(s) may be determined based on the measured signal strength(s), and may be utilized to adjust the resolution of the analog-to-digital converter.

Abstract: A system that incorporates the subject disclosure may include, for example, determining channel gains for a group of transmitters based on transmitted training symbols; and performing analog time domain cancellation and digital time domain cancellation responsive to a determination that a total interference does not satisfy a threshold range of the analog-to-digital converter, where the total interference is determined based on the channel gains. Other embodiments are disclosed.

Abstract: A communication apparatus and method in a wireless communication system that support multiple Orthogonal Frequency Division Multiplexing (OFDM) parameter sets. A method includes determining a respective OFDM parameter set for each of multiple Radio Frequency (RF) chains; and processing an OFDM signal in each of the multiple RF chains based on a parameter value defined in the respective OFDM parameter set.

Abstract: Signal-to-noise ratios (SNRs) and/or amplifier performance can be improved in crest factor reduction (CFR) applications by steering clipping noise in a different direction than the data signal achieving upon reception. Indeed, using clipping noise signals that have a different amplitude-phase relationship than the input/baseline signal causes the clipping noise signal and data signal to exhibit different antenna patterns, effectively steering the clipping noise in a different direction than the data signal. For instance, clipping noise can be steered away from potential receivers to improve received signal quality. In addition, higher magnitude clipping noise can be used to achieve improved power amplifier performance without increasing received SNR.

Abstract: Briefly, in accordance with one or more embodiments, a platform may comprise a receiver to receive a signal that includes an error in the received signal due to a noise signal generated in the platform, and a processor configured to calculate a noise vector from a source of the noise signal and to send the noise vector to the receiver, The receiver may include a digital signal processor configured to estimate an error vector based at least in part on the noise vector and to subtract the estimated error vector from the received signal to cancel the noise signal from the received signal. The noise cancelled from the received signal may include platform noise generated by a bus, a memory circuit, a clock, a power supply, a circuit ground or integrated circuit substrate, or input/output circuit of the platform.

Abstract: In a radio communication method non-contiguously using a frequency, notification information is reduced, while suppressing an effect on performance. In a communication apparatus which switches between a communication method contiguously using a frequency and a communication method non-contiguously using the frequency, sets a parameter corresponding to each communication method, and performs radio communication, the communication apparatus sets a same parameter to an entire frequency band in the communication method contiguously using the frequency, while dividing a frequency band into a plurality of frequency bands and setting a different parameter for each divided frequency band in the communication method non-contiguously using the frequency. The communication method contiguously using the frequency and the communication method non-contiguously using the frequency mutually have different PAPR (Peak to Average Power Ratio) characteristics.

Abstract: A wireless communication device configured for receiving multiple signals is described. The wireless communication device includes a single-chip carrier aggregation receiver architecture. The single-chip carrier aggregation receiver architecture includes a first antenna, a second antenna, a third antenna, a fourth antenna and a transceiver chip. The transceiver chip includes multiple carrier aggregation receivers. The single-chip carrier aggregation receiver architecture reuses at least one of the carrier aggregation receivers for secondary diversity.

Abstract: A receiver apparatus includes a propagation channel estimating unit that estimates a propagation channel. The propagation channel estimating unit includes a path detector unit that repeatedly performs a process of detecting paths in the order of increase in a propagation channel goodness of fit. The receiver apparatus that estimates a propagation channel at a high accuracy level with a small amount of calculation operation involved is thus provided.

Abstract: A system for communicating through a solid wall uses piezoelectric transducers in a multiple-input multiple-output configuration and applies crosstalk suppression. Methods of suppressing or avoiding crosstalk between parallel communication channels includes zero-forcing, eigenmode transmission, and least mean squared error processing. Orthogonal frequency division multiplexing can be used to increase transmission rates using many subchannels. Bit-loading can be used to maximize system performance.

Abstract: An outdoor radio communication system comprises a first radio unit, a second radio unit, and a single cable coupling the first radio unit to the second radio unit. Each radio unit includes a downconverter, a radio processor that is communicatively coupled to the downconverter, and a XPIC module. The cable further includes a first twisted-pair of wires for communicatively coupling the first downconverter to the second XPIC module and a second twisted-pair of wires for communicatively coupling the second downconverter to the first XPIC module. The first XPIC module generates a first reference signal using a signal from the second downconverter to cancel cross-polarization interference in an output signal of the first radio processor. Similarly, the second XPIC module generates a second reference signal using a signal from the first downconverter to cancel cross-polarization interference in an output signal of the second radio processor.

Abstract: The present invention discloses a method and a device of sending and receiving precoding information. A terminal terminal obtains a wideband precoding matrix indicator PMI. The terminal encodes an MSB of the wideband PMI to obtain encoded information. The MSB of the wideband PMI is encoded separately or jointly with other information and the MSB is a part of the wideband PMI. The terminal sends encoded information to a data sending end.

Abstract: In one embodiment, a data encoder for a component (such as an integrated circuit) may encode data to be transmitted from the component to another component in a system. The encoder may avoid one or more data patterns that, if transmitted by the component, may cause noise to occur at one or more specified frequencies (or frequency bands). The specified frequencies may be frequencies that are in use for wireless communication by the device. By avoiding noise at the specified frequencies, the desense that might otherwise occur may be reduced or eliminated. Quality and speed of the wireless communication may be increased.

Abstract: The present disclosure relates to a method for common pilot configuration, the method comprising steps of: determining information related to UEs served by a BS; and configuring transmission of at least one common pilot from the BS to the served UEs based on the determined UE related information. In an example 4-branch MIMO system, at most 4 common pilots are configurable to be transmitted, and the at least one common pilot is two common pilots newly introduced into a legacy system.

Abstract: An apparatus and method for setting a modulation frequency within a non-use frequency range so as to reduce ElectroMagnetic Interference (EMI) occurring during frequency modulation in a portable terminal are provided. The apparatus includes a controller and a frequency set unit. At frequency modulation, the controller determines whether a modulation frequency corresponds to a frequency inducing EMI. In a case where it is determined that the modulation frequency corresponds to the frequency inducing EMI, the frequency set unit resets the modulation frequency.

Abstract: Systems and methods for establishing transmission format parameters between communication devices are provided. In some aspects, a method includes identifying, by a first base station, a first communication session with a first user equipment. A master set of transmission format parameters is shared between the first base station and the first user equipment. The method also includes assigning a first subset of the master set of transmission format parameters to the first communication session. The first subset is specifically assigned to the first communication session and specifies which of the master set of transmission format parameters is allocated for use in the first communication session. The method also includes transmitting an indicator of the first subset to the first user equipment.

Abstract: A method and arrangement is proposed for adaptively generating a target noise margin for use on a DSL transmission line. The method includes determining a first quantity representing a current noise power on the line using line parameter data relating to the transmission performance of the line, determining a second quantity representing a worst-case noise power on said line using previously obtained values of the line parameter data, calculating the difference between the first and second quantities to generate a difference value, setting a target noise margin as at least equal to said difference value, and providing the target noise margin for use on the line upon initialisation of the line. In a preferred embodiment, the line parameter data is the bit loading on the line and the first and second quantities are values of the average signal-to-noise ratio on the line derived from the bit loading data.

Abstract: A method and system for dynamic configuring of one or both of a transmitter pulse-shaping filter and a receiver pulse-shaping filter to generate a total partial response that incorporates a predetermined amount of inter-symbol interference (ISI). The predetermined amount of ISI is determined based on an estimation process during extraction of data from an output of the receiver pulse-shaping filter, such that performance of total partial-response-based communication matches or surpasses performance of communication incorporating filtering based on no or near-zero ISI. The reconfiguring may comprise obtaining data relating to changes affecting one or more of: the pulse-shaping filtering, and a channel and/or an interface used in the communication of data based on the total partial response, and adjusting the filter configuration, such as by determining a new optimized filtering configuration or changes to existing configurations (e.g., by applying a filtering optimization process).

Abstract: A radio frequency communication device (100A) comprising a radio frequency communication interface (130) and a controller (110), wherein said controller (110) is configured to: transmit a message through said radio frequency communication interface (130) to a receiving radio frequency communication device (100B) using a transmission format; receive an indication on whether the reception of the message is primarily limited by noise (N) or interference (I); adapt said transmission format; and retransmit said message using said adapted transmission format.

Abstract: A non-linear detector for detecting signals with signal-dependent noise is disclosed. The detector may choose a data sequence that maximizes the conditional probability of detecting the channel data. Since the channel may be time-varying and the precise channel characteristics may be unknown, the detector may adapt one or more branch metric parameters before sending the parameters to a loading block. In the loading block, the branch metric parameters may be normalized and part of the branch metric may be pre-computed to reduce the complexity of the detector. The loading block may then provide the branch metric parameters and any pre-computation to the detector. The detector may then calculate the branch metric associated with the input signal and output the channel data.

Abstract: Techniques for improving data rates at mobile terminals that are subject to periodic channel interruptions in a beyond-line-of-sight communication system are disclosed, including improved encoding and decoding systems that identify blockages and modify receiver operation during blockages to reduce data errors. In certain embodiments, encoding, symbol mapping, interleaving, and use of unique periodic identifiers function to enable a series of packets that may be received in a blockage impaired channel with reduced errors.

Abstract: Provided is a channel state information (CSI) sharing method and apparatus in a Multiple User Multiple Input Multiple Output (MU-MIMO) environment. Each node may use network-coding to reduce overhead necessary for sharing CSI between all nodes in the MU-MIMO environment. A transmitter may dynamically select, based on the CSI between receivers, a path used for transmitting data to each receiver and a receiver to be used as a relay based on the global CSI. A decoding performance may be improved based on the CSI between the transmitter and the receivers.

Abstract: The embodiments of the present disclosure provide a WWAN test method and a test system related to the communication field, which is suitable for the product research and development stage and can derive a quantitative data relationship between a NFS test result and an OTA test result. The WWAN test method comprises: measuring a power value of noises, denoted by D(NFS), received by an antenna of a terminal to be tested in a NFS test manner; measuring a power attenuation value, denoted by D-sense, of a path from a WWAN module to the antenna of the terminal; obtaining an antenna efficiency value, denoted by AE, of the terminal; and obtaining a TIS value of an OTA test result by TIS=D(NFS)+D-sense?AE. The embodiments of the present disclosure can be used in the NFS test.

Abstract: The present disclosure relates to a receiving node, and to a related method for determining when to apply a turbo equalization mode to compensate for Inter-Symbol Interference in a radio signal received over a radio channel from a transmitting node. The method comprises decoding the received radio signal into a decoded signal, determining a current error level in the decoded signal, predicting a turbo equalization gain based on instantaneous channel information of the radio channel and deciding whether to apply the turbo equalization mode depending on the predicted turbo equalization gain and the determined current error level in the decoded signal.

Abstract: Disclosed are a sequence report method and a sequence report device for reducing a signaling amount for reporting a Zadoff-Chu sequence or a GCL sequence allocated for a cell. Indexes starting at 1 are correlated to different ZC sequences and are allocated for cells so that the indexes are continuous. When such ZC sequences are reported from BS to UE, a start index indicating the start of the continuous indexes is combined with the number of allocated sequences and they are reported as allocation sequence information by a report channel. The UE and the BS share the correlation between the ZC sequences and the indexes and the UE identifies a usable sequence number according to the correlation and the allocation sequence information reported from the BS.

Abstract: According to one embodiment, an adjacent-channel interference reject filter comprises a short-pulse inverter which includes a short-pulse sensor configured to detect a pulse in an intermediate frequency signal supplied to the device. The short-pulse sensor detects pulses having a pulse width less than or equal to some predetermined width. The short-pulse inverter also includes a pulse inverter configured to invert the pulse detected by the short-pulse sensor. The adjacent-channel interference reject filter may also include an inversion controller to control the inverting of detected short pulses. An adjacent-channel interference reject filter may be included in various devices such as wireless communication devices.

Abstract: This invention is a method and an apparatus to up link transmission of data from a user equipment to a base station for single user multiple input, multiple output. This invention includes receiving at least one codeword, permuting the received codewords, precoding the permuted codewords and transmitting the predecoded codewords on plural antennas. The codewords may be permuted by layer permutation or by codeword permutation.

Abstract: The invention relates to the field of radio signal receivers for use in wireless communication networks. In particular to a receiver unit having at least one antenna input for receiving multipath radio signals via a radio unit and at least one antenna from one or more user equipments is provided. The receiver unit comprises: a despreading unit configured to despread a multipath radio signal in the received multipath radio signals using a number of despreading fingers corresponding to a number of delay positions in the multipath radio signal which corresponds to a number of paths in the multipath radio signal, and a combining unit configured to apply at least one weight to the output of each of the number of allocated despreading fingers and combine the weighted outputs into a resulting equalized radio signal.

Abstract: A digital receiver includes a radio frequency analog front end, a digital processing unit, a plurality of cascaded amplifier stages configured to receive output of the radio frequency analog front end, a first analog to digital converter configured to convert an analog signal output from the plurality of cascaded amplifier stages into a digital signal output to the digital processing unit, a first received signal strength indicator unit configured to receive outputs of each of the plurality of cascaded amplifier stages and output signal to the digital processing unit, a second received signal strength indicator unit configured to receive output of at least one amplifier stage in the plurality of cascaded amplifier stages, and a received signal strength indicator detection unit configured to activate and to deactivate digital units according to a comparison of output from the second received signal strength indicator unit to a predetermined threshold.

Abstract: A machine-implemented system and method are described for removing interference between adjacent distributed-input-distributed-output (DIDO) clusters comprising. For example, a method according to one embodiment comprises: detecting signal strength at a first client from a main DIDO cluster; detecting interference signal strength at the first client from an interfering DIDO cluster; if the signal strength from the main DIDO cluster reaches a specified value relative to the value of the interference signal strength from the interfering DIDO cluster, then generating channel state information (CSI) defining channel state between one or more antennas of the first client and one or more antennas of the interfering DIDO cluster; transmitting the CSI from the first client to a base transceiver station (BTS) in the interfering DIDO cluster; and implementing DIDO precoding with inter-DIDO-cluster interference (IDCI) cancellation at the BTS in the interfering DIDO cluster to avoid RF interference at the first client.

Abstract: Methods and systems are provided in which a network induces different distortions in signals traversing different segments of the network. The distortions may be used to identify locations on the network of devices that transmit and receive the signals. The distortions may be reflected in equalization coefficients programmed into transmitting or receiving devices, which may be used to pre or post filter the signals to compensate for the distortions.

Abstract: A method for adaptive Radio Frequency (RF) jamming according to one embodiment includes dynamically monitoring a RF spectrum; detecting any undesired signals in real time from the RF spectrum; and sending a directional countermeasure signal to jam the undesired signals. A method for adaptive Radio Frequency (RF) communications according to another embodiment includes transmitting a data pulse in a RF spectrum; and transmitting a reference pulse separated by a predetermined period of time from the data pulse; wherein the data pulse is modulated with data, wherein the reference pulse is unmodulated. A method for adaptive Radio Frequency (RF) communications according to yet another embodiment includes receiving a data pulse in a RF spectrum; and receiving a reference pulse separated in time from the data pulse, wherein the data pulse is modulated with data, wherein the reference pulse is unmodulated; and demodulating the pulses.

Abstract: Techniques are presented to reduce the number of antennas used for a transmission for a given antenna configuration and data rate. At a wireless communication device having a plurality of antennas and capable of sending a transmission via one or more of the plurality of antennas, a determination is made of a data rate and antenna configuration to be used for a transmission. A comparison is made between a total transmit power for a minimum number of antennas for the data rate to be used for the transmission and a total transmit power associated with the antenna configuration for the transmission. When the total transmit power for a minimum number of antennas for the data rate is greater than the total transmit power associated with the antenna configuration for the transmission, the transmission is sent with the minimum number of antennas.

Abstract: A channel sounding method in a wireless local area network (WLAN) system is provided. The method, performed by a transmitter, includes transmitting a null data packet announcement (NDPA) frame to a receiver to initiate a channel sounding procedure; transmitting a null data packet (NDP) to the receiver and receiving a feedback frame. The feedback frame includes a plurality of segment frames and a channel feedback report. The channel feedback report is split into a plurality of feedback segments. Each of the plurality of feedback segments is respectively included in each of the plurality of segment frames. The each of the plurality of segment frames includes a first-segment subfield indicating whether the each of the plurality of feedback segment included is a first segment and a remaining-segment subfield indicating the number of remaining feedback segments.

Abstract: A receiver may be operable to generate estimates of transmitted symbols using a sequence estimation process that may incorporate a non-linear model. The non-linear model may be adapted by the receiver based on particular communication information that may be indicative of non-linearity experienced by the transmitted symbols. The receiver may generate a reconstructed signal from the estimates of the transmitted symbols. The receiver may adapt the non-linear model based on values of an error signal generated from the reconstructed signal, and the values of the error signal may be generated from a portion of the generated estimates that may correspond to known symbols and/or information symbols. The values of the error signal corresponding to the known symbols may be given more weight in an adaptation algorithm, and the values of the error signal corresponding to the information symbols may be given less weight in the adaptation algorithm.

Abstract: A method of compensating for an error and a transceiver system using the method. The method includes determining whether a distortion occurs in data received by a receiving unit; if it is determined that the distortion occurs in the received data, changing at least one of a plurality of transmission parameters of the received data by one step; transmitting the received data using the changed at least one transmission parameter in a transmitting unit; and repeatedly performing the determining, the changing, and the transmitting until it is determined that the distortion does not occur in the received data.

Abstract: A method is provided for transmitting channel quality information (CQI) in a MIMO system. A method for allowing a receiver to feed back a CQI value to a transmitter in a Multiple Input Multiple Output (MIMO) system includes receiving a transmission (Tx) pilot signal for each Tx antenna from a base station (BS), measuring a first CQI value of a first codeword and a second CQI value of a second codeword on the basis of the pilot signal, and transmitting the first CQI value of the first codeword and the second CQI value of the second codeword to the base station (BS), wherein at least one of the first and second CQI values includes specific information capable of indicating a transmission restriction status of a corresponding codeword.

Abstract: A device and method for precoding vectors in a communication system is provided. A transmitter may precode a data vector using information regarding a communication channel prior to transmitting the data vector. The transmitter may precode the data vector in a manner that reduces an energy value of a resulting transmit data vector so as to minimize interference in a received signal at a receiver. The transmitter may perturb entries of the data vector one-by-one in an iterative fashion until a minimum in an energy value of the transmit data vector is obtained.

Abstract: Data coding schemes perform level-based and/or transition-based encoding to avoid signaling conditions that create worst case crosstalk during transmission of multi-bit data from one circuit to another circuit via a parallel communication link. The coding schemes disallow certain patterns from being present in the signal levels, signal transitions, or a combination of the signal levels and signal transitions that occur in a subset of the multi-bit data that corresponds to certain physically neighboring wires of the parallel communication link.

Abstract: A method for transmitting digital data via a line includes the steps of providing a clock signal and of transmitting the digital data in synchrony with the clock signal, the clock signal having a frequency that is variable over time.

Abstract: A transceiver includes an input node to receive an input signal having in-phase (I) data and quadrature (Q) data, the input signal including several data samples. A correlation module determines an autocorrelation of the in-phase data, an autocorrelation of the quadrature data, a difference between the autocorrelation of the in-phase data and the autocorrelation of the quadrature data, and a cross correlation between the in-phase data and the quadrature data. An averaging module determines an average of the difference between the autocorrelation of the in-phase data and the autocorrelation of the quadrature data, and an average of the cross correlation between the in-phase data and the quadrature data, in which the averages are determined over a specified number of data samples.

Abstract: A method includes transmitting a first set of transmission signals over an operating frequency band. The method includes detecting if a second set of transmission signals are transmitted adjacent the operating frequency band and reducing power to a subset of the first set of transmission signals when the second set of transmission signals are detected.

Abstract: A system for phase noise mitigated communication including a primary transmitter that converts a digital transmit signal to an analog transmit signal, a primary receiver that receives an analog receive signal and converts the analog receive signal to a digital receive signal, an analog self-interference canceller that samples the analog transmit signal, generates an analog self-interference cancellation signal based on the analog transmit signal, and combines the analog self-interference cancellation signal with the analog receive signal and a digital self-interference canceller that samples the digital transmit signal, generates a digital self-interference cancellation signal based on the digital transmit signal, and combines the digital self-interference cancellation signal with the digital receive signal.

Abstract: Embodiments of the invention are generally directed to simultaneous transmission of clock and bidirectional data over a communication channel. An embodiment of a transmitting device includes a modulator to generate a modulated signal including a clock signal and a data signal, the clock signal being modulated by a first signal edge of the modulated signal and the data signal being modulated by a position of a second signal edge of the modulated signal; a driver to drive the modulated signal on a communication channel; an echo canceller to subtract reflected signals on the communication channel; and a data recovery module to recover a signal received on the communication channel, the received signal being encoded by Return-to-Zero (RZ) encoding, the signal being received simultaneously with driving the modulated signal on the communication channel.