Abstract: An optical reception apparatus includes: an optical coherent reception unit that receives a frequency-modulated optical signal whose optical intensity is approximately constant and generates an I-axis component of a reception signal and a Q-axis component of the reception signal based on the optical signal; a conversion unit that generates a digital signal of the I-axis component of the reception signal and a digital signal of the Q-axis component of the reception signal; a differential detection unit that generates a differential detection signal by controlling a delay amount of the digital signal of the I-axis component and a delay amount of the digital signal of the Q-axis component so that a distance between symbols on an IQ plane is increased and by performing differential detection on the digital signal of the I-axis component whose delay amount is controlled and on the digital signal of the Q-axis component whose delay amount is controlled; and an inter-symbol-distance measuring unit that measures a di

Abstract: Provided are a differential signal skew calibration circuit and a semiconductor memory. The differential signal skew calibration circuit may acquire a phase relationship of a differential signals through a phase detection circuit. A phase adjustment control circuit may generate a phase calibration control instruction according to the phase relationship of the differential signals to control a phase calibration circuit to calibrate a phase skew of the input differential signals.

Abstract: A method and system for controlling dual-connectivity service in a system where a first access node provides service on a first air interface and a second access node provides service on a second air interface, and where (i) in a single-connection-uplink mode for the dual-connectivity service, uplink user-plane communication is carried on just the second air interface and (ii) in a split-uplink mode for the dual-connectivity service, uplink user-plane communication is split between the first air interface and the second air interface. An example method includes determining an uplink Multi-User Multiple-Input-Multiple-Output (MU-MIMO) grouping efficiency of the second air interface and, based on the determined uplink MU-MIMO grouping efficiency of the second air interface, controlling whether to provide the dual-connectivity service in the single-connection-uplink mode or rather in the split-uplink mode.

Abstract: Disclosed are techniques to compensate frequency systematic known error (FSKE) in reflector or initiator radios using a hybrid RF-digital approach in multi-carrier phase-based ranging. The hybrid RF-digital approach combines a coarse frequency compensation technique in the RF domain and a fine frequency compensation technique in the digital domain to remove the FSKE across all carrier frequencies from a device. The coarse frequency compensation performed in the RF domain may use a PLL to multiply the crystal frequency to arrive close to a target carrier frequency to compensate for a coarse portion of the known FSKE at the target frequency. The fine frequency compensation may use digital techniques to remove the remaining portion of the known FSKE not compensated by the RF. The hybrid approach reduces the number of fractional bits in the multiplier of the PLL when compared to an approach that uses only the RF-PLL to remove the FSKE.

Abstract: Aspects discussed herein include a method and associated network device and computer program product. The method includes receiving a network packet, and estimating, using a preamble of the network packet, a power distribution corresponding to a plurality of subcarriers of a channel. The method further includes estimating a carrier frequency offset using the power distribution, and estimating a clock offset using the carrier frequency offset.

Abstract: A receiving station performs first signal detection processing on a received radio signal, performs a retransmission request to a transmitting station in a case in which a code error is detected in a detected radio packet for user data, and enqueues the radio packet in a reception buffer in a case in which no code error is detected. In parallel with the first signal detection processing, the receiving station performs second signal detection processing on the received signal with a longer processing delay than that of the first signal detection processing, and in a case in which no code error is detected in the detected radio packet for user data, the receiving station enqueues the radio packet in the reception buffer. The receiving station outputs, at a predetermined timing, the radio packet for user data with no code error detected, the radio packet being enqueued in the reception buffer.

Abstract: An RFID detector suitable for use in a passive RFID tag system that employs frequency hopping spread spectrum (FHSS) operation obtains an indication of at least one characteristic of a CW RF signal employing a hopped-to carrier frequency that is being transmitted from an RFID tag reader, e.g., for use in activating the RFID tag to be located, the indication of the characteristic being obtained based on a signal that is received from a source other than the RFID detector. The RFID detector may use the obtained indication of the characteristic of the CW RF signal to determine at least one position related parameter for the RFID tag. A location, e.g., of the tag, of a group of tags, of the RFID detector, or of another RFID detector, may be determined based on the position parameter.

Abstract: A variable gain phase shifter includes an I/Q generator and a vector summation circuit. The I/Q generator generates phase signals based on an input signal. The vector summation circuit adjusts magnitudes and directions of first, second, third and fourth in-phase vectors and first, second, third and fourth quadrature vectors, and generates an output signal by summing the in-phase vectors and the quadrature vectors, based on the phase signals, selection signals and current control signals. The vector summation circuit includes first, second, third and fourth vector summation cells and first, second, third and fourth current control circuits. The first and second vector summation cells adjust the directions of the first and second in-phase vectors and the first and second quadrature vectors. The third and fourth vector summation cells adjust the directions of the third and fourth in-phase vectors and the third and fourth quadrature vectors.

Abstract: An apparatus and a method for multiplying a frequency of an input signal are provided. The apparatus may include a main differential device for converting the input signal into a first differential signal and a second differential signal, a first multiplying device for outputting a first signal obtained by multiplying a frequency of the first differential signal, a second multiplying device for outputting a second signal obtained by multiplying a frequency of the second differential signal, and a compositing device for outputting a third signal obtained by combining the first signal and the second signal to remove a fundamental frequency component.

Abstract: An interface between access points is enhanced by enabling an exchange of a cell characteristic information element (IE). The cell characteristic information can provide an access point with information about the characteristics/features/capabilities of its neighbor cells. Automatic neighbor relations are also enhanced to store and/or manage the cell characteristic information. Moreover, the cell characteristic information can be utilized by the access point to significantly improve handover (HO) decisions, increase load balancing performance, and/or decrease inter cell interference. The cell characteristic information can also improve network efficiency and avoid bottlenecks during cell reselection in Heterogeneous Networks (HetNets).

Abstract: A method of detecting an obtruding signal in a radio receiver, a receiver and a computer program are disclosed. The receiver has a mixer arranged to mix a received signal to an analog baseband signal at or close to zero-frequency, a filter arranged to low-pass filter said analog baseband signal, and an analog-to-digital converter arranged to sample said filtered analog baseband signal at a sample frequency such that a digital baseband signal is formed. The method comprised receiving a radio frequency signal, mixing the radio frequency signal to the analog baseband signal at or close to zero-frequency, low-pass filtering said analog baseband signal, and analog-to-digital converting said filtered analog baseband signal at an over sample frequency such that a digital baseband signal is formed.

Abstract: A wireless device transmits a frame by determining a plurality of Resource Units (RUs) of the frame, providing pilots in a first RU of the frame at a first set of positions, providing pilots in a second RU of the frame at a second set of positions, and transmitting the frame. The first set of positions is different from the second set of positions. A wireless device receives a frame including an RU including pilots and processes the pilots. When an RU for the data symbol includes an odd-numbered lowest subcarrier, the pilots are included at a first set of positions in the resource unit. When the RU includes an even-numbered lowest subcarrier, the pilots are included at a second set of positions in the resource unit. The second set of positions is different from the first set of positions.

Abstract: Embodiments of a system and method for adapting a phase difference-based noise reduction system are generally described herein. In some embodiments, spatial information associated with a first and second audio signal are determined, wherein the first and second audio signals including a target audio inside a beam and noise from outside the beam. A signal-to-noise ratio (SNR) associated with the audio signals is estimated. A mapping of phase differences to gain factors is adapted for determination of attenuation factors for attenuating frequency bins associated with noise outside the beam. Spectral subtraction is performed to remove estimated noise from the single-channel signal based on a weighting that affects frequencies associated with a target signal less. Frequency dependent attenuation factors are applied to attenuate frequency bins outside the beam to produce a target signal having noise reduced.

Abstract: A method for pilot sequence design in a communications system includes selecting an initial cell in the communications system, and grouping other cells in the communications system relative to the initial cell into one of a neighbor group and a non-neighbor group in accordance with a neighborness measure of each of the other cells to the initial cell. The method also includes designing pilot sequences that are substantially orthogonal to one another for the initial cell and the other cells in the neighbor group, and providing information about the pilot sequences to the initial cell and the other cells in the communications system.

Abstract: A network multiple-input multiple-output (MIMO) wireless signal transmission and power control system includes a plurality of adjacently arranged cells. Each cell is a regular polygon and includes a plurality of adjoining sides, a base station located at a center of the cell, a plurality of directional antennas equipped at the base station, and a power adjustment unit electrically connected to the directional antennas. The directional antennas point towards connection points of the adjoining sides, and sectorize the cell into a plurality of kite-shaped sections by regarding the directional antennas as centers. The power adjustment unit controls power output of the directional antennas. By changing pointing directions of the directional antennas, the cell can be sectorized into the kite-shaped sections to significantly increase system capacity and communication quality.

Abstract: This disclosure provides systems, methods, and apparatus for receiving paging messages in fast fading scenarios. In one aspect, a method of demodulating a paging message during an assigned time slot by a wireless communications apparatus operating in an idle mode is provided. The method includes determining, in anticipation of the assigned time slot, an expected time position corresponding to a path of a pilot signal having a greater signal strength relative to other pilot signals. The method further includes assigning a first demodulation element to demodulate the pilot signal with reference to the expected time position and assigning a second demodulation element to demodulate the pilot signal with reference to a time offset from the expected time position. Other aspects, embodiments, and features are also claimed and described.

Abstract: Systems, devices, processors, and methods are described which may be used for the reception of a wireless broadband signal at a user terminal from a gateway via a satellite. A wireless signal may include a series of physical layer frames, each frame including a physical layer header and payload. The received signal is digitized and processed using various novel physical layer headers and related techniques to synchronize the physical layer frames and recover data from physical layer headers for purposes of demodulation and decoding.

Abstract: A method and apparatus are provided for multiplexing Uplink Control Information (UCI) with data information in a Physical Uplink Shared CHannel (PUSCH) transmitted over multiple spatial layers where aspects of the UCI multiplexing include the determination of the number of coded UCI symbols in each spatial layer when the data information is conveyed using multiple Transport Blocks (TBs), the determination of the number of coded UCI symbols in each spatial layer when the PUSCH conveys a single TB retransmission for a Hybrid Automatic Repeat reQuest (HARQ) process while the initial TB transmission for the same HARQ process was in a PUSCH conveying multiple TBs, and the determination of the modulation scheme for the coded UCI symbols.

Abstract: A technique for generating a bit log-likelihood ratio (LLR) in a communication system includes generating a demodulated signal based on a received symbol and a reference symbol. An input for a bit LLR generator is generated based on the demodulated signal and a normalization value that is based on the received symbol or the reference symbol. A bit LLR is generated for the received symbol, using the bit LLR generator, based on the input.

Abstract: A method, comprising: periodically enabling reception of a signal at a receiver, every first time; transforming the received signal in order to determine data in the received signal; comparing the determined data with reference data; and using the difference between the determined data and the reference data to estimate a correction to a multiple of the first time in order to determine a distance between the receiver and an origin of the signal.

Abstract: Methods, software, receivers and systems for communicating information over a cyclostationary channel. The method generally includes interleaving sections of a control sequence with bits of the information. The software and receivers are generally configured to implement one or more aspects of the methods disclosed herein, and the systems generally include those that embody the inventive receivers disclosed herein. The present invention is particularly useful in powerline channels, where certain parameters (such as noise) have time-dependent or periodic variations in value. By distributing the control sequence, the incidence of carrier recovery is reduced, the likelihood of successful packet or frame transmissions is increased, and data may be more reliably communicated.

Abstract: An efficient decoding of vector signaling codes is obtained using a circuit that ranks received signal levels, designates ranked values as representing particular code elements, and translates those particular code elements into a decoded result. An optimized ranking circuit combines analog crossbar switching of signal values with comparators that provide digital results. These elements may be repetitively tiled into processing arrays capable of larger ranking operations, or iteratively applied to selected portions of the data set under control of a sequencer or controller.

Abstract: In some implementations, a method of a receiver includes receiving an M-ary differential phase-shift keying (DPSK) signal containing a phase offset and optionally a phase rotation. The phase offset of the received signal may be estimated. A soft detection metric employing the estimated phase offset may be calculated to provide enhanced receiver performance. The method may include subtracting the phase offset estimate from the received signal prior to calculating the soft detection metric and/or de-rotating the phase of the received signal by the same amount of the phase rotation prior to estimating the phase offset of the received signal. Estimating the phase offset may be based on maximum likelihood principle. The soft detection metric may be a log-likelihood ratio (LLR) for soft detection of the received M-ary DPSK signal and the calculation of the LLR may be based upon a conditional joint probability density function of two consecutively received symbols.

Abstract: The present invention relates to a low power serial link employing differential return-to-zero signaling. A receiver circuit consistent with some embodiments includes an input circuit for receiving differential serial data signals that form a differential return-to-zero signaling and a clock recovery circuit. The clock recovery circuit is coupled to the input circuit and includes a logic gate configured to generate a clock signal by using said differential serial data signals.

Abstract: A time domain switching analog-to-digital converter apparatus and methods of utilizing the same. In one implementation, the converter apparatus comprises a carrier signal source, and at least one reference source. The carrier signal is summed with the input signal and the summed modulated signal is fed to a comparator circuit. The comparator is configured detects crossings of the reference level by the modulated waveform thereby generating trigger events. The time period between consecutive trigger events is used to obtain modulated signal deviation due to the input signal thus enabling input signal measurement. Control of the carrier oscillation amplitude and frequency enables real time adjustment of the converter dynamic range and resolution. The use of additional reference signal levels increases sensor frequency response and accuracy. A dual channel converter apparatus enables estimation and removal of common mode noise, thereby improving signal conversion accuracy.

Abstract: Systems and methods are provided for channel estimation using linear phase estimation. These systems and methods enable improved channel estimation by estimating a linear channel phase between received pilot subcarrier signals. The estimated linear phase can then be removed from the received pilot subcarrier signals. After the estimated linear phase is removed from the received pilot subcarrier signals, a channel response can be estimated. A final estimated channel response can be generated by multiplying the results of the linear channel estimation by the estimated linear phase.

Abstract: Disclosed herein are methods and techniques for reducing phase slips in optical communications systems and in particular methods and techniques that operate in receivers for a coherent communication system transmitting modulated data symbols exhibiting N-ary symmetrical constellation and predetermined reference symbols.

Abstract: A network node jointly precodes multi-user (MU) multiple-input multiple-output (MIMO) transmissions simultaneously sent from geographically distributed base stations to a plurality of mobile terminals over associated downlink MU-MIMO channels. The node receives feedback that describes statistics of the downlink MU-MIMO channels, including channel mean and covariance. The node then computes, based on the channel means and covariances, uplink input covariances for the mobile terminals that would collectively maximize a first or second-order approximation of the ergodic capacity of dual uplink MU-MIMO channels, subject to a global transmit power constraint that comprises the sum of individual transmit power constraints for the base stations.

Abstract: A system and method are provided for implementing a soft Reed-Solomon (RS) decoding scheme, technique or algorithm to improve physical layer performance in cable modems and cable gateways. The algorithm is implemented in a forward error correction (FEC) module connected to a QAM demodulator. The RS decoding scheme is implemented without significantly complicating hardware or processing overhead. The soft Reed-Solomon (RS) decoding scheme extracts candidate RS symbols and their Log Likelihood Ratios (LLRs) from QAM symbols. The set of highest probable candidate blocks are then chosen and these are decoded using a variant of the Chase algorithm until a valid codeword is detected at the decoder output.

Abstract: A no signal period detecting unit (10) detects a no signal period in which no receiver signal is received. A capture unit (7) captures a synchronous timing of the receiver signal on the basis of a correlation value which is worked out by a delayed correlation computing unit (6). Further, the capture unit (7) cancels the capture of the synchronous timing in the case where this no signal period is detected by the no signal period detecting unit (10).

Abstract: When a circuit that calculates a frequency offset using a shape of a frequency spectrum is implemented by hardware, the circuit size can be reduced.

Abstract: A termination network for a receiver device is provided to support both D-PHY signaling and N-factorial signaling. The first end of each of a plurality dynamically configurable switches is coupled to a common node. A first end of each of a plurality of resistances is coupled to a second end of a corresponding switch. A plurality of terminals receive differential signals and each terminal is coupled to a corresponding second end of a resistance. Each of a plurality differential receivers is coupled between two terminals of the termination network, wherein a first differential receiver and a second differential receiver are coupled to the same two terminals, the first differential receiver is used when the differential signals use a first type of differential signal encoding, the second differential receiver is used when the differential signals use a second type of differential signal encoding.

Abstract: A signal demodulation module is disclosed. The signal demodulation module includes an injection-locked oscillator, an envelope detector and a data slicer. The injection-locked oscillator has a central oscillating frequency equal to a frequency of a digital modulation signal received, and outputs a phase-locked oscillating signal which is in phase to the digital modulation signal. When input phase of the digital modulation signal changes, output phase of the injection-locked oscillator changes synchronously. The envelope detector is used for detecting an envelope line of the phase-locked oscillating signal and outputting an envelope signal accordingly. The data slicer is used for receiving the envelop signal and outputting a first digital signal according to a reference voltage and the envelop signal.

Abstract: A system for estimating clock frequency offset and sampling clock offset in a communication system is provided. A receiver is configured to receive a communication signal having been transmitted from a transmitter via a communication channel. The receiver has a signal processor, wherein the signal processor is configured to generate an estimate of a carrier frequency offset and an estimate of a sampling clock offset from the received communication signal by: extracting a vector of pilot symbols from the received signal; performing equalization on the pilot symbols; performing clock frequency offset and sampling clock offset compensation on the pilot symbols; generating the estimate of a carrier frequency offset by estimating a common phase rotation using a first Taylor series approximation; and generating the estimate of the sampling clock offset by estimating phase differences between pairs of pilot symbols using a second Taylor series approximation.

Abstract: A FFR (fractional frequency reuse)-based network MIMO (multiple-input multiple-output) transmission architecture in a cellular system that employs cell sectoring using directional antennas. Each cell is sectorized into three outer sectors using three directional antennas which transmit in three different directions using three different frequency subbands. The cell sectors are arranged based on a frequency partition scheme so that three sectors in three neighboring cells form a coordinated group for network MIMO transmission. A regular and a rearranged frequency partition are described. Further, a practical implementation of SON (self organizing network)-based three-cell FFR-based network MIMO for a wireless OFDM system is described.

Abstract: The present invention discloses a method and apparatus for wide dynamic range phase conversion. In one embodiment, inphase and quadrature signal components of a complex input signal are collapsed into a single quadrant to produce a first signal representation. A scaling operation is subsequently performed on the first signal representation to produce a second signal representation. Lastly, the second signal representation is converted into the phase domain.

Abstract: A system includes a DPSK transmitter and a DPSK receiver. The DPSK transmitter is configured to encode a signal and transmit the encoded signal as a sequence of symbols. The DPSK receiver is configured to decode the sequence of symbols into bit values. The DPSK receiver further includes a first decoder which is configured to receive the sequence of the symbols, and to estimate extrinsic information for each symbol and forward the extrinsic information to a second decoder. Moreover, if magnitude of a LLR received form a second decoder is greater than a threshold, the first decoder is configured to determine a bit value of a received symbol, without considering neighboring symbols in the sequence of symbols. Still moreover, if the magnitude of the LLR received from the second decoder is not greater than the threshold, the first decoder is configured to continue to decode the received symbol and consider neighboring symbols in the sequence of symbols.

Abstract: A method and apparatus for decoding binary frequency shift key signals in which an exclusive-OR of the sign of a real waveform with a sign of the imaginary waveform at a time shortly after the real (or, alternatively, the imaginary) waveform crosses zero is used to determine a bit represented by the signal. In some embodiments, particularly those in which the bit period is about one-half of the carrier signal frequency, both the real and imaginary waveforms are monitored to detect the zero crossing in order to account for the situation in which data transitions prevent zero-crossings on one of the waveforms.

Abstract: A transmitting system, a receiving system, a transmitting method and a receiving method capable of implementing communications with multiple rates are described.

Abstract: Systems and methods are provided for channel estimation using linear phase estimation. These systems and methods enable improved channel estimation by estimating a linear channel phase between received pilot subcarrier signals. The estimated linear phase can then be removed from the received pilot subcarrier signals. After the estimated linear phase is removed from the received pilot subcarrier signals, a channel response can be estimated. A final estimated channel response can be generated by multiplying the results of the linear channel estimation by the estimated linear phase.

Abstract: A differential phase shift keying demodulator having an input structured to receive current data representing a current phasor and past data representing at least two past phasors, and a phase differentiator structured to process the current data and reference data representing a reference phasor to provide resulting data representing a phase difference between said current and reference phasors. The differential phase shift keying demodulator also includes a reference phasor computational module configured to generate said reference data basing on said past data representing the at least two past phasors.

Abstract: A quadrature signal phase controller includes a first phase shifter and a second phase shifter. The first phase shifter generates phase shifted first in-phase differential output signals and phase shifted first quadrature-phase differential output signals. The second phase shifter generates phase shifted second in-phase differential output signals and phase shifted second quadrature-phase differential output signals. Each of the first and second phase shifters increases or decreases the phase difference between the first in-phase differential output signals and the second quadrature-phase differential output signals, and the phase difference between the second in-phase differential output signals and the first quadrature-phase differential output signals, in response to a change in a level of the first control signal and a change in a level of the second control signal.

Abstract: A variation on conventional DPSK binary modulation schemes is provided. One modulation scheme uses 3?/8 differential binary phase shift keying (3?/8-DBPSK) where one symbol is transmitted by phase change of 3?/8 radians and the other symbol is transmitted by phase change of ?5?/8 radians. Alternatively, this can be thought of as adding a constant 3?/8 radians to the symbol angle for every bit modulated by conventional DBPSK. In another example, assume a first and second symbols, k?1 and k, respectively, are sent. Where k is the same symbol as k?1, a phase rotation of 3?/8 radians from the kth symbol is used to represent the symbol at k?1; and where the k?1 symbol is the opposite of the kth symbol, its rotation 11?/8 radians from the kth symbol. Other modulation schemes using other phase rotations can be provided.

Abstract: The invention relates to a EHF wireless communication receiver comprising a phased array radio arranged for receiving a beam of signals in a predetermined frequency band. The phased array radio comprises a plurality of antenna paths, each arranged for handling one of the incoming signals and forming a differential I/Q output signal, each antenna path comprises a downconversion part and a phase shifting part for applying a controllable phase shift; a signal combination circuitry is connected to the antenna paths and is arranged for combining the differential I/Q output signals; and a control circuitry is connected to the phase shifting parts of the antenna paths and is arranged for controlling the controllable phase shift. In each antenna path, the phase shifting part is a baseband part downstream from the downconversion part and the phase shifting part comprises a set of variable gain amplifiers arranged for applying controllable gains to the respective downconverted incoming signals in the I/Q branches.

Abstract: A method and device is provided for detecting data symbols in a received radio signal. Each data symbol is allocated transmit-side a symbol value-specific PN sequence of successive PN chips in the chip clock, and the allocated PN sequences are offset QPSK modulated. The method for incoherent detection includes converting the received radio signal into a complex baseband signal sampled in the chip clock, generating a demodulated signal by differential demodulation of the complex baseband signal, calculating correlation results by correlating the demodulated signal with the derived sequences, and deriving the values of the data symbols by evaluating the correlation results. Each derived sequence is assigned to a PN sequence allocable transmit-side and includes derived chips, whose values correspond to a logic linking of particular PN chips of the PN sequence allocable transmit-side that is assigned the derived sequence. The invention relates furthermore to a corresponding receiving unit.

Abstract: A method (500) of demodulation, the method comprising the steps of receiving (510) a radio frequency signal, converting (520) the received radio frequency signal to a baseband signal, performing (530) symbol timing recovery on the baseband signal, and demodulating (540) the baseband signal. The baseband signal comprises alternating symbols spaced therebetween at an alternating first interval length and a second interval length, where the first interval length and second interval length are dissimilar. Communication units and a method of modulation are also described.

Abstract: A method and apparatus are provided for low power simultaneous frequency, automatic gain control and timing acquisition in a low power radio receiver. A baseband signal received is split into a limited signal having limited data and a non-limited signal. The limited signal is fed through a limited phase-shift keying (PSK) correlation path in which a PSK correlator operating on the limited signal simultaneously determines coarse frequency estimations, timing estimations, and packet synchronization detection. The non-limited signal is fed through an automatic gain control path where automatic gain control is performed on the non-limited signal simultaneously with the coarse frequency and timing estimations and packet synchronization detection performed by the PSK correlator.

Abstract: A differential encoding and decoding system and method for multiplexed data is disclosed. The multiplexed data is formed from a plurality of input data sources. The differential encoding and decoding uses a delay proportional to the number of input data streams in the plurality. In this fashion, errors that propagate from an error in one of the input data sources does not interfere with other input data sources upon de-multiplexing.

Abstract: An automatic zero-crossing signal demodulation and classification device for rapidly identifying unknown modulation in a signal identifies unknown modulation in a signal, demodulates differential phase shift keying signals and automatically recognizes certain phase shift keying signals. This is accomplished by eliminating unknown term fc in differential phase estimation, introducing a symbol rate tracking mechanism, applying hysteresis nonlinearity to eliminate phase shaping effect and using weighted average to estimate phase difference. Better estimates are accomplished by using hysteretic nonlinear function to detect zero-crossing points in eliminating false detecting of zero-crossing points caused by additive noise, and calculating differential phase without directly using center frequency to simplify estimation process.

Abstract: A method and device for multi-user detecting of an OFDM transmission signal are provided. The method includes: combining received signals, at corresponding time-frequency symbol positions in all of multiple repeated Block Units in relation to the same data symbol, into a received data sequence; determining a combined repeated channel response sequence array corresponding to the received data sequence; and detecting the received data sequence using the combined repeated channel response sequence array to obtain data symbols of multiple users. The technical solution can effectively restrain the multi-address interference and the interference between symbols during OFDM transmitting signal and improve the system performance greatly.