Class / Patent application number | Description | Number of patent applications / Date published |
375348000 | Intersymbol interference | 52 |
20080219388 | SUCCESSIVE INTERFERENCE CANCELLATION BASED ON THE NUMBER OF RETRANSMISSIONS - A method for processing a plurality of symbol streams is provided. The method includes receiving a first symbol stream, wherein the first symbol stream has a corresponding first number of retransmissions. The method further includes receiving a second symbol stream, wherein the second symbol stream has a corresponding second number of retransmissions. The method further includes selecting the first symbol stream for decoding, if the first number of retransmissions is greater than the second number of retransmissions. | 09-11-2008 |
20080219389 | Feed-forward cancellation in wireless receivers - A method of suppressing interference from remote transmitters operating to a first standard having frequencies overlapping those for a receiver operating to a second standard is provided. Such interference being increasingly common as a result of the deployment of multiple wireless transceivers within electronic devices either supporting multiple international standards, such as WiFi and WiMAX, or within typical wireless environments. Advantageously, the invention presents a means of actively cancelling interference from transmitters operating within the same frequency range as defined by the standard. The active cancellation accordingly allows improved performance for systems with very low received signal powers, such as GPS, in addition to wireless data communications standards. An exemplary embodiment providing active cancellation through delaying the portion of the received signal according to the first standard adjusting both the amplitude and phase by means of polar modulation prior to summing this signal with the received signal to provide a receive signal within which the first standard signal is nulled. Control of the polar modulator being determined in the exemplary embodiment by minimizing received power after passband limiting filters. | 09-11-2008 |
20080260080 | Narrowband Interference Cancellation Method and Apparatus - A Cartesian Feedback-loop Signal Canceller (CFSC) recovers a signal of interest from a composite signal by cancelling a narrowband interferer from the composite signal. According to one embodiment, narrowband interference cancellation is performed by destructively combining a composite signal including a narrowband interference signal and a signal of interest with an estimate of the narrowband interference signal to generate an interference-compensated signal. A feedback signal is generated having Cartesian components derived from the interference-compensated signal. Cartesian components associated with the signal of interest are removed from the feedback signal to generate the narrowband interference signal estimate. | 10-23-2008 |
20080292036 | Method and Device for Signal Processing | 11-27-2008 |
20080298524 | Interference Suppression in a Multicarrier Receiver - A receiver uses knowledge of pilot symbols transmitted by a neighboring sector to reduce interference in a received data symbol. The received data symbol is transmitted on one or more data subcarriers in a first sector. Overlapping pilot symbols transmitted on overlapping pilot carriers in a second sector are determined and used to generate channel estimates for the overlapping pilot carriers. The overlapping pilot symbols and pilot channel estimates are then used to reduce interference in the received data symbol. | 12-04-2008 |
20080310564 | Processing data in a digital communications system - A method of processing a signal in a wireless digital communications system, wherein a source of disturbance affects differently at least first and second portions of a received signal carrying user data and/or control data, the method comprising: identifying the second portion of the received signal, most affected by the source of disturbance; generating a first estimate of the disturbance (P | 12-18-2008 |
20080310565 | Dynamic optimization of overlap-and-add length - A method of adjusting overlap-and-add length for zero-padded suffixes. The method includes, based on a channel impulse response, estimating an effective channel length. When the effective channel length is less than a default overlap-and-add length and greater than a minimum length, the method includes setting the overlap-and-add length to the effective channel length. When the effective channel length is less than the minimum length, the method includes setting the overlap-and-add length to the minimum length. When the effective channel length is greater than the default overlap-and-add length, the method includes setting the overlap-and-add length to the default overlap-and-add length. | 12-18-2008 |
20080317179 | Method And Apparatus For Pipelined Joint Equalization And Decoding For Gigabit Communications - A method and apparatus for the implementation of reduced state sequence estimation is disclosed, with an increased throughput using precomputation (look-ahead), with only a linear increase in hardware complexity with respect to the look-ahead depth. The present invention limits the increase in hardware complexity by taking advantage of past decisions (or survivor symbols). The critical path of a conventional RSSE implementation is broken up into at least two smaller critical paths using pipeline registers. Various reduced state sequence estimation implementations are disclosed that employ one-step or multiple-step look-ahead techniques to process a signal received from a dispersive channel having a channel memory. | 12-25-2008 |
20090067558 | METHOD FOR ESTIMATING, IN A COMMUNICATION SYSTEM, THE LEVEL OF INTERFERENCE PLUS NOISE AFFECTING RECEIVED SIGNALS REPRESENTATIVE OF A SET OF RECEIVED PILOT SYMBOLS - The present invention concerns a method for estimating, in a communication system, a level of interference plus noise affecting received signals representative of a set of received pilot symbols, characterized in that the method comprises the steps of:
| 03-12-2009 |
20090067559 | SYSTEM AND METHOD FOR HIGH-SPEED DECODING AND ISI COMPENSATION IN A MULTI-PAIR TRANSCEIVER SYSTEM - A method and a system for providing ISI compensation to an input signal in a bifurcated manner. ISI compensation is provided in two stages, a first stage compensates ISI components induced by characteristics of a transmitter's partial response pulse shaping filter, a second stage compensates ISI components induced by characteristics of a multi-pair transmission channel. First stage ISI compensation is performed in an inverse response filter having a characteristic feedback gain factor K, during system start-up. Second stage ISI compensation is performed by a single DFE in combination with a MDFE operating on tentative decisions output from a Viterbi decoder. As the DFE of the second stage reaches convergence, the feedback gain factor K of the first stage is ramped to zero. | 03-12-2009 |
20090103670 | PSEUDO-ECHO CANCELLATION PROCESSING APPARATUS, PSEUDO-ECHO CANCELLATION METHOD AND DIGITAL-BROADCAST RECEIVING APPARATUS - Disclosed herein is a pseudo-echo cancellation processing apparatus including: a correlator for computing a complex mutual-correlation value, that is, the value of a mutual correlation between the real part of a complex baseband signal of a received input-signal sequence and a reference-signal sequence included in the input-signal sequence as well as the value of a mutual correlation between the imaginary part of the complex baseband signal and the reference-signal sequence; and a processing section configured to carry out processes of: pre-storing complex vectors each representing pseudo-echo components; detecting a complex mutual-correlation value having a peak of powers of the complex mutual-correlation values; delaying the detected complex mutual-correlation value by a delay time corresponding to successive symbols; carrying out a complex multiplication operation; and adding a complex mutual-correlation value to an original complex mutual-correlation value. | 04-23-2009 |
20090129522 | APPARATUS AND METHOD FOR PARALLEL SYMBOL CANCELLATION FOR SPATIAL MULTIPLEXING IN MULTIPLE INPUT MULTIPLE OUTPUT SYSTEM - An apparatus and method for parallel symbol cancellation in a Multiple Input Multiple Output (MIMO) system supporting spatial multiplexing. The method includes selecting one of four quadrants representing all points on a constellation having normalization distribution, selecting a single reference point in the selected quadrant and generating a reference value corresponding to the single reference point, generating addition values for representing other points than the single reference point using a difference of a size of each of the points having the normalization distribution, and summing up the reference value and the addition values. The apparatus includes modules configured for performing the parallel symbol cancellation with reduced complexity. | 05-21-2009 |
20090168931 | METHOD AND APPARATUS FOR JITTER COMPENSATION IN RECEIVER CIRCUITS USING NONLINEAR DYNAMIC PHASE SHIFTING TECHNIQUE BASED ON BIT HISTORY PATTERN - The present invention provides a simple, easy to implement method and apparatus to reduce jitter in a channel and expand the eye width and eye height of the eye pattern of the signal. The method and apparatus of the present invention reduces jitter specific to a channel in a high speed interface. The present invention utilizes a phasing shifting mechanism based on history of the incoming bits at the receiver. The input bits from the channel are shifted in time before getting to the receiver. This approach significantly reduces Intersymbol Interference (ISI) and deterministic jitter, thus opening up the eye width and eye height for a given interface. | 07-02-2009 |
20090290666 | METHOD AND APPARATUS FOR RECEIVER PULSE RESPONSE DETERMINATION - A pulse response for a receiver, as an array PR, is found from the receiver's symbol stream. For a continuous stream of arbitrary data, a value of the array PR[k] can be determined from the signal levels of the symbols received. The stream of received data is input to a FIFO. Between the first and last locations of the FIFO is the symbol referred to herein as D | 11-26-2009 |
20100040180 | Adaptive noise filtering and equalization for optimal high speed multilevel signal decoding - A Signal Conditioning Filter (SCF) and a Signal Integrity Unit (SIU) address the coupled problem of equalization and noise filtering in order to improve signal fidelity for decoding. Specifically, a received signal can be filtered in a manner to optimize the signal fidelity even in the presence of both significant (large magnitudes of) ISI and noise. The present invention can provide an adaptive method that continuously monitors a signal fidelity measure. Monitoring the fidelity of a multilevel signal can be performed by external means such as by the SIU. A received signal y(t) can be “conditioned” by application of a filter with an electronically adjustable impulse response g(t). A resulting output z(t) can then be interrogated to characterize the quality of the conditioned signal. This fidelity measure q(t) can be used to adjust the filter response to maximize the fidelity measure of the conditioned signal. | 02-18-2010 |
20100080329 | INFORMATION PROCESSOR AND INFORMATION PROCESSING METHOD, DISPLAY DEVICE, AND PROGRAM - Disclosed herein is an information processor, including: a receiving section configured to receive an OFDM signal transmitted in accordance with an OFDM system; a FFT arithmetically operating section configured to carry out FFT for a signal within a predetermined interval of the OFDM signal; a delay profile estimating section configured to estimate delay profiles from the OFDM signal received by the receiving section; an inter-symbol interference amount estimating section configured to estimate inter-symbol interference amounts for a plurality of candidates for the predetermined interval, respectively, by using the delay profiles estimated by the delay profile estimating section; and a searching section configured to search for the candidate having the minimum inter-symbol interference amount estimated by the inter-symbol interference amount estimating section from among the plurality of candidates in the predetermined interval, and supply data on the candidate thus searched for as the predetermined interval to the FFT arithmetically operating section. | 04-01-2010 |
20100080330 | RECEIVING APPARATUS, RECEIVING METHOD, AND PROGRAM - Disclosed herein is a receiving apparatus including: first to third position determination sections configured to determine the start position of an FFT interval which serves as a signal interval targeted for FFT by an FFT section; a selection section configured to select one of those start positions of the FFT interval which are determined by the first through the third position determination section; and the FFT section configured to perform FFT on the OFDM time domain signal by regarding the start position selected by the selection section as the start position of the FFT interval in order to generate the first OFDM frequency domain signal. | 04-01-2010 |
20100128828 | METHODS AND APPARATUS FOR ADAPTING ONE OR MORE EQUALIZATION PARAMETERS BY REDUCING GROUP DELAY SPREAD - Methods and apparatus are provided for adapting one or more equalization parameters in a communications system by reducing group delay spread. According to one aspect of the invention, one or more equalization parameters in a communications system are adapted by detecting one or more predefined run length patterns in a received signal, such as a plurality of consecutive same-valued bits; evaluating a transition latch value for each of the detected predefined run length patterns, wherein the transition latch value provides an indication of whether the received signal is under-equalized or over-equalized; and adjusting the one or more equalization parameters of the communications system based on the evaluation of the transition latch value. The adjusted equalization parameters may be employed to equalize intersymbol interference. A data eye monitor can be employed to evaluate the transition latch value. | 05-27-2010 |
20100142664 | RECEIVER, METHOD OF RECEPTION, RECEPTION PROGRAM, INTEGRATED CIRCUIT, AND DIGITAL TELEVISION - A receiver which allows suitable setting of the position of an FFT (Fast Fourier Transform) window (execution timing) when executing FFT to demodulate an OFDM (Orthogonal Frequency Division Multiplex) signal. The receiver estimates the transmission path property of a received OFDM signal and estimates an ISI (Inter Symbol Interference) amount in each case of a plurality of FFT window position candidates from the estimated transmission path property. An FFT window position candidate wherein the ISI amount is estimated to be the smallest among the FFT window position candidates is set as an actual FFT window posiion, and executes Fourier transformation. | 06-10-2010 |
20100220826 | INTER-SYMBOL INTERFERENCE CANCELLATION FOR WIRELESS MULTIPLE ACCESS - An interference-canceling receiver is configured for cancelling inter-symbol interference due to both inter- and intra-channel interference in coded, multiple-access, spread spectrum transmissions that propagate through frequency-selective communication channels. The receiver mitigates the effects of post-cursor inter-symbol interference using feedback of previously estimated symbols, and mitigates pre-cursor inter-symbol interference using an interference canceller, such as an iterative interference canceller. | 09-02-2010 |
20110069796 | Advanced Signal Processors for Interference Suppression in Baseband Receivers - A multi-mode receiver includes a channel decomposition module (e.g., a Rake receiver) for separating a received signal into multipath components, an interference selector for selecting interfering paths and subchannels, a synthesizer for synthesizing interference signals from selected sub channel symbol estimates, and an interference canceller for cancelling selected interference in the received signal. At least one of the channel decomposition module, the synthesizer, and the interference canceller are configurable for processing multi-mode signals. | 03-24-2011 |
20110150153 | Apparatus and Method for Inter-Carrier Interference Cancellation - A method for inter-carrier interference cancellation is provided. A time-domain received signal is detected to obtain information of an inter-symbol interference free region. Multiple cyclic useful symbols are obtained from the time-domain received signal according to the information of the inter-symbol interference free region and a set of multi-step windowing coefficients is generated. Adjusted cyclic useful symbols are obtained by multiplying the cyclic useful symbols by the set of multi-step windowing coefficients, respectively, and then combined in a time domain to obtain a time-domain combination signal. The inter-carrier interference of each of sub-carriers of the time-domain combination signal is centralized on neighboring D sub-carriers. The time-domain combination signal is transformed into a frequency-domain received signal. The frequency-domain received signal and its corresponding channel response matrix are divided into overlapped signal blocks according to D. Successive inter-carrier interference cancellation is performed on each signal block in parallel to obtain estimation data. | 06-23-2011 |
20120093272 | RECEIVING DEVICE, RECEIVING METHOD, AND PROGRAM - A receiving device includes a channel estimating section that performs a correlating process for a received reference signal in which a single carrier signal was transformed into a frequency domain signal and a pre-stored reference signal so as to obtain estimated channel values; a compensation coefficient computing section that computes compensation coefficients corresponding to residual multipath interferences based on a bit likelihood; a weight computing section that computes equalized weights based on the estimated channel values and the compensation coefficients; an equalizing filter that generates an equalized signal by equalizing process for the received signal that is the frequency domain signal based on the equalized weights; a residual interference replica generating section that generates residual multipath interference replicas based on frequency domain symbol replicas, the estimated channel values, and the equalized weights; and a subtracting section that subtracts the residual multipath interference replicas from the equalized signal. | 04-19-2012 |
20120183107 | METHOD AND SYSTEM FOR ADAPTIVE GUARD INTERVAL (GI) COMBINING - A method and system for combining a guard interval and a corresponding portion of a received symbol, whereby when receiving a signal that contains the symbol with a guard interval corresponding to the symbol, a portion of the guard interval that is free from inter-symbol interference may be extracted, and the extracted portion of the guard interval may be combined with the corresponding portion of the symbol. The extracting and combining may be done after a determining, based on a delay profile provided by the received signal, that a delay spread is smaller than a predetermined channel delay. The delay spread may be determined by filtering an instantaneous delay spread associated with the received signal. The filtering may be performed using a 1-tap infinite impulse response low-pass filter. The low-pass filter may include a time constant that is the inverse of a maximum Doppler frequency shift. | 07-19-2012 |
20120207257 | METHOD AND APPARATUS FOR OFFSET ESTIMATION IN MOBILE COMMUNICATION SYSTEM - A method and an apparatus for estimating an offset are provided. The method includes determining one of a frequency offset and a timing offset to be estimated first for pilot symbols detected from a received signal, estimating one of the frequency offset and the timing offset for the pilot symbols according to the determination, compensating for an offset of the pilot symbols based on the estimated offset, and estimating remaining one of the frequency offset and the timing offset which is not estimated for the offset compensated pilot symbols. | 08-16-2012 |
20130064335 | ADAPTIVE NOISE FILTERING AND EQUALIZATION - Processing a signal comprising signal distortions with filters. The filters comprise a first filter configured to a first time scale to compensate for signal distortions within respective symbols of the signal and a second filter configured to a second time scale to compensate for signal distortions among symbols of the signal. A probability estimate is produced based on an output of at least one of the first and second filters. At least one of the first and second time scales is adjusted according to the probability estimate. | 03-14-2013 |
20130329840 | SYSTEM AND ALGORITHM FOR MULTIPATH MITIGATION - A system and method for optimally combining multi-path signals is presented. A first signal is received that traveled a first path from a transmitter to a receiving location and a second signal is received that traveled a different second path from the transmitter to the same receiving location. The paths are different so that the first and second signals contain the same signal data but the first signal has a first distortion that is different than a second distortion in the second signal. According to an objective function, the method adaptively generates a first weight value and a second weight value. The first and second weight values are applied to the respective first and second signals to produce respective first and second weighted signals. The first and second weighted signals are linearly combined producing a combined signal with a combined signal degradation. | 12-12-2013 |
20140044223 | Rake Receiver - There is provided a rake receiver for a femtocell base station, the rake receiver being for use in receiving a multipath signal, the rake receiver comprising a plurality of fingers, and wherein the rake receiver is adapted to assign multiple fingers to the same path in the multipath signal. | 02-13-2014 |
20140098915 | ADAPTIVE NON-LINEAR MODEL FOR HIGHLY-SPECTRALLY-EFFICIENT COMMUNICATIONS - 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. | 04-10-2014 |
20140133611 | WIRELESS COMMUNICATION APPARATUS AND ONE-PATH STATE DETERMINATION METHOD - A wireless communication apparatus includes a wireless unit configured to receive a radio signal; and a signal processing unit configured to detect a phase shift between a detection timing of a path relevant to the received signal at the wireless unit and a path timing of the received signal, to calculate interference power by a first path having a maximum power value based on the phase shift, to calculate power of one or more second paths other than the first path based on the interference power, and to determine whether the received signal is received in a one-path state or a multi-path state based on the power value of the first path and the power values of the one or more second paths. | 05-15-2014 |
20140133612 | FREQUENCY DIVISION MULTIPLEXING SYSTEM WITH SELECTABLE RATE - An OFDM system uses a normal mode which has a symbol length T, a guard time TG and a set of N sub-carriers, which are orthogonal over the time T, and one or more fallback modes which have symbol lengths KT and guard times KTG where K is an integer greater than unity. The same set of N sub-carriers is used for the fallback modes as for the normal mode. Since the same set of sub-carriers is used, the overall bandwidth is substantially constant, so alias filtering does not need to be adaptive. The Fourier transform operations are the same as for the normal mode. Thus fallback modes are provided with little hardware cost. In the fallback modes the increased guard time provides better delay spread tolerance and the increased symbol length provides improved signal to noise performance, and thus increased range, at the cost of reduced data rate. | 05-15-2014 |
20140146928 | CONVOLUTIONAL DEINTERLEAVING APPARATUS AND ASSOCIATED METHOD - A convolutional deinterleaving apparatus includes a memory and a control module. The control module stores a plurality of sets of data into the memory according to a deinterleaving rule. The plurality of sets of data are of a same group. After determining a representative channel state indicator according to an N number of channel state indicators corresponding to an N number of sets of data in the group, the control module stores the representative channel state indicator into the memory. The N number of sets of data of the same group correspond to a same carrier frequency. | 05-29-2014 |
20140177767 | METHOD AND APPARATUS FOR JOINT EQUALIZATION AND DECODING OF MULTIDIMENSIONAL CODES TRANSMITTED OVER MULTIPLE SYMBOL DURATIONS - Techniques are provided for performing joint equalization and decoding of multidimensional codes transmitted over multiple symbol durations. A reduced state sequence estimation (RSSE) decoder is provided for a multidimensional code. A multidimensional code symbol comprises a number of symbol components of lower dimensionality. The RSSE decodes comprises at least one branch metric unit that calculates branch metrics for a received signal based on intersymbol interference and intrasymbol interference estimates, the at least one branch metric unit compensating for intrasymbol interference caused by symbol components within a current multidimensional code symbol; and a decision feedback unit that processes survivor symbols to calculate the intersymbol interference estimates for different code states of the multidimensional code and channels used to transmit the multidimensional code. | 06-26-2014 |
20140185722 | System and Method for Optimizing Use of Channel State Information - The present invention relates to a combiner, channel identifier, Orthogonal Frequency Division Multiplexing OFDM receiver and method for optimizing use of channel state information of a received signal. The method comprises analyzing a received signal in a time domain and extracting from the received signal characteristics of a communication channel. The method furthermore comprises determining a dynamic indicator of channel station information accuracy based on the characteristics of the received signal. Additionally, the method comprises applying a weight to the channel state information according to the dynamic indicator. | 07-03-2014 |
20140241477 | DECISION FEEDBACK EQUALIZER FOR HIGHLY SPECTRALLY EFFICIENT COMMUNICATIONS - One or more embodiments describe a decision feedback equalizer for highly spectrally efficient communications. A method may be performed in a decision feedback equalizer (DFE). The method may include initializing values of tap coefficients of the DFE based on values of tap coefficients of a partial response filter through which said transmitted symbols passed en route to said sequence estimation circuit. The method may include receiving estimates of transmitted symbols from a sequence estimation circuit, and receiving an error signal that is generated based on an estimated partial response signal output by the sequence estimation circuit. The method may include updating values of tap coefficients of the DFE based on the error signal and the estimates of transmitted symbols. The method may include generating one or more constraints that restrict the impact of the error signal on the updating of the values of the tap coefficients of the DFE. | 08-28-2014 |
20140247911 | Partial Response Receiver And Related Method - A multi-phase partial response equalizer circuit includes sampler circuits that sample an input signal to generate sampled signals in response to sampling clock signals having different phases. A first multiplexer circuit selects one of the sampled signals as a first sampled bit to represent the input signal. A first storage circuit coupled to an output of the first multiplexer circuit stores the first sampled bit in response to a first clock signal. A second multiplexer circuit selects one of the sampled signals as a second sampled bit to represent the input signal based on the first sampled bit. A second storage circuit stores a sampled bit selected from the sampled signals in response to a second clock signal. A time period between the second storage circuit storing a sampled bit and the first storage circuit storing the first sampled bit is substantially greater than a unit interval in the input signal. | 09-04-2014 |
20140247912 | Method and Apparatus for Correcting in-Phase Signal and Quadrature-Phase Signal - The present invention discloses a method for correcting an IQ signal. includes: saving an I signal of a last frame and a Q signal of the last frame that are output by a receiving front end; eliminating a direct-current offset of an I signal of a current frame and a direct-current offset of a Q signal of the current frame according to the I signal of the last frame and the Q signal of the last frame; and geometrically correcting an I signal of the current frame after direct-current offset elimination and a Q signal of the current frame after direct-current offset elimination according to an I signal of the last frame after direct-current offset elimination and a Q signal of the last frame after direct-current offset elimination to obtain a corrected I signal of the current frame and a corrected Q signal of the current frame. | 09-04-2014 |
20140294129 | SLOPE DETECTING RECEIVER - A receiver for receiving digital data after transmission through a channel which produces inter-symbol interference or other distortion. In one embodiment, a received signal is differentiated before being digitized to form an output digital bit stream, to reduce the effects of inter-symbol interference and other distortion in the channel. The differentiated signal is compared to two threshold values, a first threshold value, and a second threshold value, the first threshold value being greater than the second threshold value. When the differentiated signal exceeds the first threshold, the output bit is 1, when the differentiated signal is less than the second threshold value, the output bit is 0, and when the differentiated signal is between the first threshold value and the second threshold value, the output bit is the same as the previous output bit. | 10-02-2014 |
20140301510 | Method of Channel Cancellation, Radio Receiver, Cellular Communication Device and Computer Program - A method of channel cancellation for a cellular communication device is disclosed. The method comprises receiving ( | 10-09-2014 |
20140301511 | METHOD AND SYSTEM FOR MULTIPATH FINGERPRINTING BY MAXIMUM DISCRIMINATION TECHNIQUES - Discriminative methods for multipath fingerprinting, enabling single-site localization in rich multipath environments, are provided herein. In contrast to the existing descriptive method that uses only the data of each location for its fingerprint extraction, these methods use also the data of the other locations in the database, and leverage it to make the fingerprint as different as possible from the other fingerprints in the database. The performance of these methods, validated with both simulated and real data, is superior to the existing method, demonstrating localization accuracy of about 1 m in typical indoor environments. | 10-09-2014 |
20140328439 | METHOD TO INCREASE SIGNAL-TO-NOISE RATIO OF A CYCLIC-PREFIX ORTHOGONAL FREQUENCY-DIVISION MULTIPLEX SIGNASL - A method to decode an orthogonal frequency-division multiplex (OFDM) signal data block that includes symbol-data in a data interval, repeated-data in a cyclic-prefix (CP) guard interval, and noise. The signal is often called a CP-OFDM signal. The method includes determining a first data set based on data samples taken during a first time window of a data block. The method also includes determining a second data set based on data samples taken during a second time window of the data block, wherein the second time window is selected so that the second data set includes repeated-data not present in the first data set. The method also includes combining the first data set and the second data set in a manner effective to increase a signal-to-noise ratio of the signal. The combining process increases signal data energy more than noise data energy. | 11-06-2014 |
20140362958 | COMPUTING SYSTEM WITH INTERFERENCE CLASSIFICATION MECHANISM AND METHOD OF OPERATION THEREOF - A computing system includes: an antenna configured to receive a receiver signal for representing a serving signal and an interference signal; a communication unit, coupled to the antenna, configured to: calculate a decoding result based on the receiver signal, generate an interference modulation estimate based on the decoding result and the receiver signal, and calculate a content result based on the interference modulation estimate for representing the serving signal. | 12-11-2014 |
20150030109 | FREQUENCY DIVISION MULTIPLEXING SYSTEM WITH SELECTABLE RATE - An OFDM system uses a normal mode which has a symbol length T, a guard time TG and a set of N sub-carriers, which are orthogonal over the time T, and one or more fallback modes which have symbol lengths KT and guard times KTG where K is an integer greater than unity. The same set of N sub-carriers is used for the fallback modes as for the normal mode. Since the same set of sub-carriers is used, the overall bandwidth is substantially constant, so alias filtering does not need to be adaptive. The Fourier transform operations are the same as for the normal mode. Thus fallback modes are provided with little hardware cost. In the fallback modes the increased guard time provides better delay spread tolerance and the increased symbol length provides improved signal to noise performance, and thus increased range, at the cost of reduced data rate. | 01-29-2015 |
20150043686 | Methods and Systems for Channel Estimation - A method for channel estimation of a signal by a receiver, comprises the steps of: receiving a symbol of the signal, wherein the signal has a cyclic prefix (“CP”); combining a portion of the CP and an end portion of the symbol; and processing the combined symbol for channel estimation by the receiver. | 02-12-2015 |
20150063507 | FBMC RECEIVER WITH CARRIER FREQUENCY OFFSET COMPENSATION - The invention concerns a filter bank receiver (FBMC) effecting a carrier frequency offset compensation in the frequency domain. The receiver comprises an FFT module extended by the overlap factor ( | 03-05-2015 |
20150117576 | TIMING SYNCHRONIZATION APPARATUS AND METHOD FOR MULTI-CARRIER MODULATION SIGNALS - Embodiments of the present invention provide a timing synchronization apparatus and method for multi-carrier modulation signals. Wherein the apparatus includes: a predicting unit configured to denoise delay of symbols received before a currently received symbol, and to predict delay of the currently received symbol or of a symbol received after the currently received symbol according to the denoised symbol delay and a sampling clock frequency offset; and a timing synchronization unit configured to perform timing synchronization according to a predicted value of the delay of the currently received symbol or of the symbol received after the currently received symbol. With the apparatus and method, a signal to noise ratio of multi-carrier modulation signals may be effectively improved, and an effect of a timing error on a communication system may be lowered, thereby improving performance of the communication system. | 04-30-2015 |
20150296413 | METHODS AND APPARATUS FOR ADAPTING TRANSMITTER CONFIGURATION FOR EFFICIENT CONCURRENT TRANSMISSION AND RADAR DETECTION THROUGH ADAPTIVE SELF-INTERFERENCE CANCELLATION - Certain aspects of the present disclosure relate to adapting transmitter configuration for efficient concurrent primary user detection through adaptive self-interference cancellation. A wireless transmitting device may schedule a transmission in a shared spectrum. The device may scan at least a portion of the shared spectrum during the transmission to receive a signal. Interference caused by the transmission may he cancelled from the received signal using self-interference cancellation circuitry. The device may determine whether the received signal indicates usage by a primary user of the shared spectrum. In an aspect, the transmission may be a SISO transmission. In another aspect, carrier aggregation may be used for the transmission and a potential carrier may be subject to primary user detection. The device may determine a self-interference cancellation complexity for a combination of carriers including the potential carrier, and may select one or more carriers for aggregation based on the self-interference cancellation complexity. | 10-15-2015 |
20150304136 | Partial Response Receiver And Related Method - A multi-phase partial response equalizer circuit includes sampler circuits that sample an input signal to generate sampled signals in response to sampling clock signals having different phases. A first multiplexer circuit selects one of the sampled signals as a first sampled bit to represent the input signal. A first storage circuit coupled to an output of the first multiplexer circuit stores the first sampled bit in response to a first clock signal. A second multiplexer circuit selects one of the sampled signals as a second sampled bit to represent the input signal based on the first sampled bit. A second storage circuit stores a sampled bit selected from the sampled signals in response to a second clock signal. A time period between the second storage circuit storing a sampled bit and the first storage circuit storing the first sampled bit is substantially greater than a unit interval in the input signal. | 10-22-2015 |
20160065393 | METHOD FOR GENERATING A FILTER BANK FOR RECEIVING A SIGNAL MODULATED BY CONTINUOUS PHASE MODULATION, AND METHOD FOR RECEIVING SAID SIGNAL - A method for generating a filter bank for receiving a signal modulated by continuous phase modulation, the modulated signal being able to be broken down as a sum of a plurality of amplitude-modulated signals, each amplitude-modulated signal being expressed by a product between a complex pseudo-symbol and a temporal component with a waveform predefined according to the parameters of the modulation, comprises: evaluating, over a duration T that is equal to the duration of a symbol, all possible waveforms of the signal from the parameters of the continuous phase modulation and the breakdown in the form of a sum of a plurality of amplitude-modulated signals, retaining all evaluated waveforms that are different from one another, constructing a filter bank made up of a plurality of filters whose temporal responses are equal to the retained waveforms, which are limited to a duration equal to the duration of a symbol. | 03-03-2016 |
20160164702 | OPTIMIZED RECEIVERS FOR FASTER THAN NYQUIST (FTN) TRANSMISSION RATES IN HIGH SPECTRAL EFFICIENCY SATELLITE SYSTEMS - An approach is provided for increasing transmission throughput rates for a source signal transmitted over a wireless channel, applying faster-than-Nyquist (FTN) signaling rates combined with tight frequency roll-off to the a source signal. A receiver is provided that compensates for ISI effects induced by the FTN rate and tight frequency roll-off, where the complexity of the receiver grows only linearly with the interference memory. The receiver comprises an equalizer configured to compensate for the ISI effects, and a decoder configured to decode the output of the equalizer to determine and regenerate the source signal. The receiver processes the received signal via a plurality of processing iterations. For one processing iteration, the decoder generates a set of a posteriori soft information based on the output of the equalizer, and the equalizer uses the a posteriori soft information as a priori soft information for a subsequent processing iteration. | 06-09-2016 |
20160191174 | Soft Packet Combining for Superposition Coding - A method is proposed to enable a UE performing codeword level interference cancellation (CW-IC) to know whether an interfering transport block (TB) is a new transmission or retransmission. With this knowledge, the UE knows whether the soft channel bits stored in a soft buffer are to be discarded or combined with the soft channel bits newly obtained. | 06-30-2016 |
20160380658 | RECEIVER CIRCUIT AND ASSOCIATED METHOD CAPABLE OF CORRECTING ESTIMATION OF SIGNAL-NOISE CHARACTERISTIC VALUE - A receiver circuit capable of correcting an estimation of a signal-noise characteristic value (e.g., SNR) is provided. The receiver circuit includes an equalizer, a slicer, an estimation circuit and a correction circuit. The equalizer provides an equalized signal according to a received signal. The slicer interprets digital information in the equalized signal and accordingly provides a sliced signal. The estimation circuit provides an initial signal-noise characteristic value according to a difference between the equalized signal and the sliced signal. The correction circuit provides a corresponding correction value according to the initial signal-noise characteristic value, and corrects the initial signal-noise characteristic value according to the corresponding correction value to generate a corrected signal-noise characteristic value. | 12-29-2016 |