Patent application number | Description | Published |
20080317102 | Method and Apparatus for Interference Suppression in a Wireless Communication Receiver - According to methods and apparatus taught herein, a parametric model of received signal impairment correlations includes a parametric model term that accounts for a dominant receiver but does not result in any significant increase in parametric modeling complexity. In more detail, the parametric model models the dominant interferer as a spatial interferer, which is hypothesized as a point source of interference emanating along single-path channels to each of two or more receiver antennas. The dominant interferer thus is represented in terms of its spatial correlation across receiver antennas. The dominant interferer model term may be included in an overall model fitting process, or it may be fitted separately. Regardless, the spatial modeling approach taught herein may be used for WCDMA and other systems, and may be embodied in essentially any type of linear equalizer receiver structure. | 12-25-2008 |
20090003301 | HS-PDSCH BLIND DECODING - The number of blind decoding operations in a wireless communication receiver is reduced. In one embodiment, a candidate set of transport formats is formed by eliminating one or more allowed transport formats, thus reducing the number of decode operations to be performed. In another embodiment, a received data transmission is partially decoded according to each of a plurality of transport formats, and decode quality metrics associated with each transport format are inspected. Only the transport formats yielding sufficiently high quality metrics are utilized to fully decode the transmission. In other embodiments, upon failure to successfully decode a received transmission, it is assumed to be a retransmission with a missed control transmission, and one or more transport formats specifying the position of a previous transmission in a buffer are added to the candidate set of transport formats. The received retransmission and previously received transmission are then HARQ combined and decoded. | 01-01-2009 |
20090003377 | Reliable Decoding of a High-Speed Shared Control Channel - Methods and apparatus are disclosed for detecting a control channel message transmitted on one of a plurality of shared control channels and targeted to a wireless receiver. In an exemplary method, messages transmitted over a plurality of shared control channels are decoded, and at least one likelihood metric is determined for each of the decoded messages. A best candidate is selected from the decoded messages, based on the likelihood metrics, and the at least one likelihood metric for the best candidate is compared to corresponding likelihood metrics for the messages other than the best candidate to determine whether the best candidate is a valid message. Wireless communication receivers configured correspondingly are also disclosed. | 01-01-2009 |
20090034666 | IQ Imbalance Image Suppression - A WCDMA receiver performs baseband suppression of the image signal component caused by IQ imbalance. An IQ imbalance image scaling factor is computed from conventional channel estimates and estimates of the IQ imbalance image channel, the latter computed using a conjugated scrambling sequence as the reference sequence for despreading. An IQ imbalance image estimate is obtained by scaling the complex conjugate of the received signal by the IQ imbalance image scaling factor, and is subtracted from the input signal prior to applying traditional baseband demodulation algorithms. | 02-05-2009 |
20090036079 | IQ Imbalance Image Suppression in Presence of Unknown Phase Shift - A wireless communication system receiver compensates a received signal containing an IQ gain imbalance prior to performing frequency correction. The IQ gain imbalance in the signal is estimated after frequency correction, providing an IQ gain imbalance estimate for subsequent IQ gain imbalance compensation. The IQ gain imbalance estimation includes formulating a plurality of hypotheses of phase error between I and Q signal components, and taking as the actual phase error the hypothesis that yields the maximum power ratio between I and Q signal components. The maximum power ratio is differentiated with respect to the IQ imbalance estimate. The IQ gain imbalance estimate is updated as a function of its prior value(s), the maximum power ratio, and the derivative of the maximum power ratio. | 02-05-2009 |
20090080557 | Quality of Service Based Antenna Mapping for Multiple-Input Multiple-Output Communication Systems - The teachings presented herein provide methods and apparatus for use in a multiple-input multiple-output (MIMO) system transmitting a plurality of data substreams to a receiver employing ordered successive interference cancellation detection according to a predetermined sequence for decoding the data substreams. In an exemplary method, a quality of service (QoS) requirement is determined for each of two or more application-specific data streams, and the application-specific data streams are assigned to the data substreams according to the determined QoS requirements and the predetermined sequence, so that application-specific data streams having more stringent QoS requirements are decoded earlier than application-specific data streams having less stringent QoS requirements. In some embodiments, the determined QoS requirements comprise maximum delay requirements, and application-specific data streams requiring shorter maximum delays are assigned to earlier-decoded data substreams than application-specific data streams having less stringent maximum delay requirements. In other embodiments, the determined QoS requirements comprise an application-specific robustness, wherein application-specific data streams corresponding to less robust applications are assigned to earlier-decoded data substreams than application-specific data streams corresponding to more robust applications. | 03-26-2009 |
20090268787 | Method and Apparatus for Compensating for Processing Timing Misalignment in a Communication Receiver - According to the teachings presented herein, a wireless communication apparatus compensates for timing misalignment in its received signal processing. In at least one embodiment, the apparatus estimates a set of path delays for a received signal and sets processing delays on the estimated path delays. The apparatus jointly hypothesizes combinations of fractional timing offsets for two or more paths, and computes a decision metric for each joint hypothesis that indicates the accuracy of the joint hypothesis. As non-limiting examples, the decision metric may be a signal quality metric, or a distance metric (such as between a measured net channel response and an effective net channel response reconstructed as a function of the combination of fractional timing offsets included in the joint hypothesis). The apparatus evaluates the decision metrics to identify a best estimate of timing misalignment, and correspondingly compensates coherent processing of the received signal. | 10-29-2009 |
20090316591 | Method and Apparatus for Generating Channel Quality Estimates - A base station receives channel quality reports from a plurality of mobile terminals. The channel quality reports from the mobile terminals indicate the signal power of the signals received by the mobile terminals from the base station and one or more interference parameters relating to the power of impairment components contributing to the total impairment of the received signal during a first time interval. The base station computes an estimated channel quality indication for a second time interval subsequent to the first time interval based on expected variations in the powers of the impairment components. The estimated channel quality indication for the second time interval is used by the base station to schedule the mobile terminals and to determine the transmission format. | 12-24-2009 |
20100054309 | NONPARAMETRIC MIMO G-RAKE RECEIVER - With a nonparametric G-Rake receiver, combining weights may be determined using a nonparametric mechanism in multiple-input, multiple-output (MIMO) scenarios. In an example embodiment, a method for a receiving device having a nonparametric G-Rake receiver entails calculating an impairment covariance matrix and determining combining weights. More specifically, the impairment covariance matrix is calculated based on a pilot channel using a nonparametric mechanism in a MIMO scenario in which a code-reuse interference term exists. The combining weights are determined for the nonparametric G-Rake receiver responsive to the impairment covariance matrix and by accounting for the code-reuse interference term. | 03-04-2010 |
20100054373 | Method and Apparatus for Low-Complexity Interference Cancellation in Communication Signal Processing - The teachings herein disclose interference cancellation processing that uses hard decision logic for simplified estimation of interfering signals, in combination with soft scaling of the hard decisions for better interference cancellation performance, particularly in low signal quality conditions. In one aspect, the soft scaling may be understood as attenuating the amount of interference cancellation applied by a receiver, in dependence on the dynamically changing received signal quality at the receiver. More attenuation is applied at lower signal quality because the hard decisions are less reliable at lower signal qualities, while less (or no) attenuation is applied at higher signal qualities, reflecting the higher reliability of the hard decisions at higher signal qualities. Signal quality may be quantized into ranges, with a different value of soft scaling factor used for each range, or a soft scaling factor may be calculated for the continuum of measured signal quality. | 03-04-2010 |
20100056170 | Methods and Apparatus for Improving Cell-Edge Data Throughput in a Wireless Communications System - Methods and apparatus for adaptively transmitting data in a wireless communication network are disclosed, in which channel conditions between a mobile terminal and two or more base stations in an active set are evaluated and used to select a transmission mode from a set of available downlink transmission modes including a non-interference-coordinated point-to-point transmission mode as well as at least one of a multi-cell single-frequency-network transmission mode and an interference-coordinated point-to-point transmission mode. Using the dynamic transmission mode selection described herein, a higher cell-edge throughput in HSDPA systems may be achieved. | 03-04-2010 |
20100081403 | Rake Receiver and a Method of Allocating Fingers in a RAKE Receiver - A RAKE receiver is adapted to receive input from at least a first and a second antenna ( | 04-01-2010 |
20100088578 | Parity Bit Soft Estimation Method and Apparatus - The systematic and parity bits of a symbol are tightly coupled to each other based on the way in which the symbol is encoded. The relationship between the systematic and parity bits can be exploited to improve the accuracy of soft bit estimation for both the systematic bits and parity bits. In one embodiment, a received symbol is processed by demodulating the received symbol to determine an initial soft estimate of each systematic bit and corresponding one or more parity bits in the sequence. The systematic bit sequence is iteratively decoded to revise the soft estimate of the systematic bit. The initial soft estimate of the one or more parity bits associated with each systematic bit is revised based on the revised soft estimate of each systematic bit. The received symbol can be decoded or regenerated based on the revised soft estimate of each systematic bit and corresponding one or more parity bits. | 04-08-2010 |
20100098194 | Method and Apparatus for Simplified Expected Symbol Value Computation and Interference Cancellation in Communication Signal Processing - A computationally-simplified approach to expected symbol value determination is based on classifying soft bit information corresponding to symbols in a received communication signal as being reliable or unreliable, and computing expected symbol values for the symbols based on the classified soft bit information. Classification can be carried out by “quantizing” the soft bit information to coarsely indicate whether individual symbol bits are known with high or low probability. Using quantized soft bit information greatly simplifies expected symbol value calculation, yet the calculated values still reflect a scaling corresponding to the underlying reliability of the soft bit information. Where the expected symbol values are computed for interfering symbols in a composite signal that also includes desired signals, preserving the underlying reliability knowledge in this manner effectively scales the amount interference cancellation applied to the composite signal in dependence on the reliability to which the interfering signal values are known. | 04-22-2010 |
20100159862 | Method and Apparatus for Frequency Control in Wireless Communications - The automatic frequency correction value applied by a receiver is altered to minimize long-term drift of a path delay profile. In one embodiment, the phase or timing error resulting from constant frequency corrections is accumulated, and an estimated frequency correction value is selectively quantized into an actual frequency correction value in response to the accumulated phase/timing error. The quantized value above or below the estimate is selected to minimize the accumulated phase/timing error that gives rise to path delay profile drift. In another embodiment, a timing circuit measures the instantaneous path delay profile drift incurred with each frequency correction, and integrates the instantaneous drift measurements over time to yield a path delay profile drift. The drift (or its rate of change) is then used to adjust a frequency correction value so as to minimize the drift. | 06-24-2010 |
20100208847 | OFDM Receiver for Dispersive Environment - A received OFDM signal is processed to determine a plurality of reference delays, which may include the path delays of a multipath channel. The effective channel estimates corresponding to each reference delay are determined, as is the covariance of the ISI and noise components observed at each delay. Combining weights resulting in maximum post-combining SINR are determined for all subcarriers. A corresponding plurality of FFTs is applied to the incoming sample stream, one at each of the reference delays. The individual subcarriers from each FFT output are then combined using the combining weights. This produces a single FFT output with suppressed ISI, which is used in further processing. | 08-19-2010 |
20100284443 | Channel Estimation - A user terminal is configured to generate supplemental pilot symbols from data symbols transmitted to other user terminals meeting a predetermined reliability criterion. The supplemental pilot symbols can be used for channel estimation, covariance estimation, CQI estimation, or other purposes. | 11-11-2010 |
20110007793 | JOINT TIME/FREQUENCY PROCESSING FOR WIRELESS RECEIVERS - Channel estimation and/or equalization processing is performed in a wireless receiver in two stages. The first stage involves pre-filtering in the frequency domain to compact a grid-based representation of the net channel. The second stage involves implementing reduced-complexity time domain channel estimation and/or equalization. According to one embodiment, a received signal transmitted over a net channel is processed by pre-filtering the received signal in the frequency domain. The frequency domain pre-filtering compacts an N-tap effective grid-based representation of the net channel into a K-tap compacted grid-based representation of the net channel where K01-13-2011 | |
20110188591 | Method and Apparatus for Impairment Correlation Estimation in MIMO Systems - The teachings herein disclose methods and apparatus that simplify impairment correlation estimation for received signal processing, based on determining, for any given processing interval, which impairment contributors should be considered in the estimation of overall received signal impairment correlations. These simplifications reduce computational processing requirements, allowing reduced circuit complexity and/or reduced operating power, and improve receiver performance. A corresponding transmitter and transmission method include transmitting multiple information streams to targeted receivers according to ongoing scheduling, and controlling the ongoing scheduling to reduce the number of impairment contributors considered in impairment correlation estimation at the targeted receivers. In one embodiment, a receiver identifies which impairment contributors to consider based on receiving control information. In another embodiment, the receiver identifies the impairment contributors to consider based on background processing, e.g., background determination of parametric model fitting parameters for a plurality of impairment contributors, and observing those model fitting parameters over time. | 08-04-2011 |
20110206107 | Blind SIR Estimation Using Soft Bit Values - An SIR estimate of a communication signal in a wireless communication system receiver is calculated based on soft bit values output by a nonlinear detector. The average amplitude of the detector output soft bits is estimated. The average power of the detector output soft bits is estimated, e.g., as a mean-square or variance. An SIR of the communication signal is estimated based on the soft bit amplitude and power estimates. In particular, the SIR is estimated as the ratio of the square of soft bit amplitude to the difference between the mean square soft bit power and the square of soft bit amplitude, or the ratio of the square of soft bit amplitude to the variance. In either case, the SIR estimate may be scaled to obtain the desired units. The communication signal may be a received signal, or a simulated signal generated using channel estimates obtained from, e.g., a pilot channel. | 08-25-2011 |
20110206167 | Data-Aided SIR Estimation - A signal-to-interference estimate is generated using unknown data symbols in place of or in addition to pilot symbols. Data received over a data channel (traffic channel or control channel) are collected. The data symbols are then used to compute an observation metric based on deviations of the data symbols from a predetermined set of possible data symbols, wherein one of the data symbols and symbol constellation is normalized. A data channel signal-to-interference ratio is then computed based on the observation metric. | 08-25-2011 |
20110250857 | Interference Avoidance in White Space Communication Systems - Mobile communication system equipment avoids interfering with another transmitter's operation. Sensing information indicating whether the other transmitter's signal has been detected is received from remote sensors, wherein each of the remote sensors is situated at a respective one of two or more sensor locations. The sensing information and information about the sensor locations is used to ascertain one or more exclusion boundaries needed to avoid interfering with the other transmitter's use of the spectral resource. Beamforming parameters are ascertained that will enable the main node to transmit within one or more predefined geographical areas except for any portion of a predefined area located on a far side of the one or more exclusion boundaries. Two or more adjusted signals are produced as a function of the beamforming parameters and one or more signals to be transmitted. The adjusted signals are transmitted from respective ones of two or more antennas. | 10-13-2011 |
20110250921 | Omni-Directional Sensing of Radio Spectra - Multiple antennas used for data transmission and/or reception are also used to achieve omni-directional antenna functionality. Signals from the antennas are converted to baseband and stored. Phase shifts are applied to the stored signals to steer the effective reception beam in one of a number of directions. A process of interest (e.g., white space sensing) is applied to the beam to produce a result for the given beam direction. By scanning the beam over a number of representative directions, a spatial receiver range equivalent to that of an omni-directional antenna is achieved. | 10-13-2011 |
20120188951 | Preferential Allocation of Different Length Scrambling Codes - A base station herein assists a radio network controller (RNC) to allocate scrambling codes in a cell. The base station's assistance advantageously permits the RNC to allocate different length scrambling codes to different mobile terminals (or downlink carriers) in the cell. Specifically, the base station determines a preference for whether the length of a scrambling code to be allocated to each terminal or carrier should be short or long, based on whether uplink communications transmitted by the terminal, or downlink communications transmitted over the carrier, are to be processed with a high-complexity receiver or a low-complexity receiver. The RNC receives these preferences from the base station and takes them into account in order to allocate either a short scrambling code or a long scrambling code to each terminal or downlink carrier in the cell. The RNC then propagates the scrambling code allocations throughout the cell. | 07-26-2012 |
20120189083 | Interference Cancellation Based On Interfering Link IL Signal Quality And Related Methods And Devices - A target link signal may be received at a receiving device with the target link signal being received in a received signal also including an interfering link signal. A quality of the interfering link signal in the received signal may be estimated at the receiving device to provide an estimated interfering link signal quality. One of a plurality of interference cancellation techniques may be selected responsive to the estimated interfering link signal quality, and an interference cancellation signal may be generated using the selected one of the plurality of interference cancellation techniques. Information of the interference cancellation signal may be incorporated in the received signal. Responsive to incorporating information of the interference cancellation signal in the received signal, the received signal may be demodulated to provide a demodulated target link signal, and the demodulated target link signal may be decoded to provide a target link bit stream. | 07-26-2012 |
20120201319 | METHOD AND ARRANGEMENT FOR POLARIZATION CONTROL IN A COMMUNICATION SYSTEM - Controlling the polarization state of signals to be transmitted from a MIMO capable radio base station node to a plurality of user equipment, which radio base station node comprises a precoder unit connecting a first and a second virtual antenna port to a respective first and second transmit antenna port, by the steps of controlling (S | 08-09-2012 |
20120219155 | METHODS AND DEVICES FOR ALLOCATING SCRAMBLING CODES - Methods and devices are provided whereby scrambling codes can be set in an improved way. In accordance with one embodiment a method is provided in a User Equipment for generating a second scrambling code or a second scrambling code group. The UE is configured for multi carrier operation receiving downlink transmission from a Universal Mobile Telecommunications System Terrestrial Radio Access Network on a set of at least two downlink carriers including an anchor carrier and at least a first secondary carrier. The method comprises determining a first scrambling code or a first scrambling code group associated with a first cell on the anchor carrier; and deriving a second scrambling code or a second scrambling code group associated with a second cell on said first secondary carrier using a predefined rule defining the relation between the second scrambling code or second scrambling code group and the first scrambling code or scrambling code group. Hereby interference suppression/cancellation processing is enabled in a receiver of a UE on secondary cells in multi-carrier scenarios that do not transmit the SCH, while minimizing the need for overhead in terms of signaling of the scrambling codes for neighbouring cells in a UTRAN system. Methods and devices for E-UTRAN are also described. | 08-30-2012 |
20120252446 | Fast Radio Access Technology Detection for Cell Search - Methods and apparatus are provided for detecting the radio access technology (RAT) employed in a received signal prior to performing a cell search. The RAT detection method may be used to identify the most likely RAT employed for each candidate frequency identified in an initial frequency scan. Once the most likely RAT is identified, the mobile communication device can then attempt synchronization according to the procedures for the most likely RAT. Identifying the RAT prior to the cell search reduces the number of synchronization attempts and, consequently, the time needed to perform the cell search. | 10-04-2012 |
20120263061 | Method and Apparatus for Generating Channel Quality Estimates - A base station receives channel quality reports from a plurality of mobile terminals. The channel quality reports from the mobile terminals indicate the signal power of the signals received by the mobile terminals from the base station and one or more interference parameters relating to the power of impairment components contributing to the total impairment of the received signal during a first time interval. The base station computes an estimated channel quality indication for a second time interval subsequent to the first time interval based on expected variations in the powers of the impairment components. The estimated channel quality indication for the second time interval is used by the base station to schedule the mobile terminals and to determine the transmission format. | 10-18-2012 |
20120300754 | Scheduling of Up-Link Transmissions of a Wireless Communication System - A method is disclosed of scheduling up-link transmissions for a number of terminals of a wireless communication system into a number of groups, wherein each group comprises terminals intended for simultaneous up-link transmission during a respective period of time. A subset metric may be calculated for each of a number of subsets of terminals based on transmissions received from the terminals of the subset. The subset metric is indicative of a simultaneous transmission suitability measure for the terminals of the subset. The subsets may be processed in subset metric order, starting with the subset having a subset metric indicating a least suitability metrics for of simultaneous transmission. During the processing, each terminal of the subset that is not already scheduled in a group may be scheduled in a group that does not already comprise another terminal of the subset. Information indicative of the period of time during which a scheduled terminal is intended to transmit may be transmitted to each of the scheduled terminals. Corresponding computer program product, scheduler and arrangement are also disclosed. | 11-29-2012 |
20130077578 | SIGNALING OF OTHER-CELL SIGNAL'S CONFIGURATION INFORMATION TO FACILITATE INTERFERENCE CANCELLATION AT A MOBILE TERMINAL - In MU-MIMO scenarios, a target mobile terminal can be exposed to data streams intended for other mobile terminals. If the target mobile terminal is capable of interference cancellation, then a serving base station can provide the target mobile terminal with interference information so that the target mobile terminal can efficiently cancel interferences due to these interfering data streams. The interference information includes one or more configuration information, each of which characterizes a related interfering data stream. The serving base station provides the interference information over one or more radio resources that are exclusive allocated to the target mobile terminal or are allocated for common listening. The serving base station exchanges configuration information with neighboring base stations over inter-BS links. The inter-BS links use resources that are different from the radio resources used between the base stations and the mobile terminals. | 03-28-2013 |
20130114429 | Method and Apparatus for Identifying Other User Equipment Operating in a Wireless Communication Network - The present invention includes a method and apparatus for autonomously determining by a first UE the identities (IDs) of one or more other UEs that are operating in or around the same network area as the first UE. More particularly, the first UE determines with a defined reliability the UE ID of an otherwise unknown UE based on receiving and processing an HS-SCCH transmission targeted to the unknown UE. By learning actual UE IDs for one or more other UEs operating in or around the same area as the first UE, the first UE can then properly decode HS-SCCH transmissions to those other UEs, and thereby gain knowledge of the signal structures used for data (HS-PDCH) transmissions to those other UEs. Advantageously, the first UE applies such knowledge in its desired-signal receiver processing, such as for enhancing channel estimation and/or performing structured-signal interference cancellation. | 05-09-2013 |
20130136087 | Method and Apparatus for Impairment Correlation Estimation in MIMO Systems - A method of transmitting communication signals to a plurality of targeted receivers includes transmitting one or more information streams for individual ones of the targeted receivers according to ongoing transmission scheduling, and controlling the ongoing transmission scheduling to reduce the number of impairment contributors that must be considered in received signal processing by scheduled ones of the targeted receivers. In one embodiment the controlling comprises scheduling the targeted receivers to avoid transmissions to more than one targeted receiver at a time. In the same or another embodiment, the controlling comprises at least one of using equal transmit power allocations for one or more information streams, and using fixed transmit power allocations for one or more of the information streams. | 05-30-2013 |
20130148699 | NON-REDUNDANT EQUALIZATION - Communication signal processing entails generating an overall signal correlation estimate that reflects overall impairment present in a received signal before despreading. Processing further includes parametrically constructing one or more component-specific correction terms as a function of one or more component signal correlation estimates, each estimate reflecting a particular component of the overall impairment. Combining weights are derived, as a function of this overall estimate and the correction term(s), so that they exclude the contribution of the impairment component(s) to the overall impairment. These weights are used to combine signal samples in an equalization process. As the combining weights exclude the contribution of the impairment component(s) to the overall impairment, the equalization process utilizing the weights exclusively suppresses impairment that is not attributable to the component(s). This advantageously avoids redundant suppression of the impairment component(s), since processing further includes despreading the received signal in a despreading process that suppresses the component(s). | 06-13-2013 |
20130195166 | Robust Frequency-Domain Equalization in Communications Receivers - MMSE equalization in the frequency domain is emulated by applying intermediate weights on a per-frequency-bin basis and re-scaling each bin output to recover proper MMSE scaling. Time-domain samples of a received signal are transformed into a frequency-domain representation of the received signal. A frequency-domain representation of a channel response for the radio channel is calculated, and a frequency-domain representation of impairments to the desired signal is generated, the frequency-domain representation of the impairments comprising an impairment covariance matrix for each of the frequency bins. A scaling factor for each of frequency bins is calculated, based on a bin-specific signal-quality estimate for each bin, and an equalized frequency-domain sample for each of the frequency bins is computed, as a function of the scaling factors, the frequency-domain representation of the channel response, and the generated frequency-domain representation of impairments. The equalized frequency-domain samples are transformed into an equalized time-domain sample sequence. | 08-01-2013 |
20130198591 | Method and Apparatus for Soft Information Transfer between Constituent Processor Circuits in a Soft-Value Processing Apparatus - In one or more aspects, the present invention improves the efficiency of soft information transfer within a soft-value processing apparatus, by reducing in some sense the “amount” of soft information transferred between constituent processor circuits within the apparatus, without forfeiting or otherwise compromising the transfer of “valuable” soft information. In one example, the soft values produced by a constituent processor circuit are identified as being reliable or unreliable according to a reliability threshold. Some or all of the unreliable values are omitted from a soft value information transfer to another constituent processor circuit, or they are quantized for such transfer. The reduction in memory requirements for soft information transfer advantageously allows the use of lower power, less complex, and less expensive circuitry than would otherwise be required in the apparatus, which may be, as a non-limiting example, a Turbo receiver in a wireless communication device. | 08-01-2013 |
20130202063 | Extending the Set of Addressable Interferers for Interference Mitigation - Techniques for expanding the set of addressable interfering signals in an interference cancelling receiver are described, where the task of control message detection from interfering cells is integrated in an iterative receiver process where increasingly better a priori information on the received data signals from the previous iteration is used to detect additional control messages and successively grow the set of interfering signals included in the receiver's interference mitigation processing. In an example method, first estimated symbols for a desired signal are generated. A control channel corresponding to a first interfering signal is detected, where said detecting is based on the first estimated symbols. Signal characteristics information for the first interfering signal is then derived from the detected control channel signal, and used to generate second estimated symbols for the desired signal, using an interference-mitigation technique to mitigate the effects of the interfering signal. | 08-08-2013 |
20130301686 | Chip-Level Processing for Joint Demodulation in CDMA Receivers - A CDMA multi-code joint demodulation solution in which impairment suppression and channel matching operations are performed prior to despreading. Embodiments include a linear front end that performs chip-level suppression of signal components that are not included in a subsequent joint demodulation process. The pre-processing stage also carries out metric preparation and provides a vector decision statistic that is processed by a joint demodulation stage to extract per-code soft values for the symbols of interest in the received signal. Both code-specific and code-averaged versions of the linear processing are disclosed, as are several front-end configurations with equivalent performance, but different complexity trade-offs. These new approaches use a block formulation, requiring a set of input chip samples as an input, and perform all operations as matrix-vector multiplications, which is an approach amenable to efficient DSP or hardware implementation. | 11-14-2013 |
20130301758 | Method and Apparatus for Turbo Receiver Processing - One aspect of the present invention concerns the management of processing resource allocations for a Turbo receiver, where such resources are consumed from a finite resource budget within a defined processing time interval. The contemplated Turbo receiver attempts to allocate more processing resources to those demodulation and/or Turbo decoding tasks that make more valuable contributions with respect to the ultimate goal of successfully decoding all data streams that are of interest in a received signal. The advantageous management approach allows the Turbo receiver to obtain better results for a given consumption of processing resources, and further permits the Turbo receiver to quit upon either achieving a successful outcome within a defined processing time interval or exhausting the budgeted resources. | 11-14-2013 |
20140092947 | Adaptive Smoothing of Channel Estimates - Techniques for directly adapting the parameters of a smoothing filter used for channel estimation to the current velocity and signal-to-noise ratio (SNR) situation. An example method begins with a plurality of channel response measurements. For each of a first subset of a set of pre-determined filter responses, the channel measurement samples are filtered to obtain a corresponding set of estimated channel response samples. Next, for each set of estimated channel response samples, a corresponding set of ordered residuals are calculated from the channel measurement samples. Each set of ordered residuals is evaluated to determine a measure of correlation among the ordered residuals, and an updated filter response is selected from a second subset of the set of pre-determined filter responses, based on this evaluation, for use in demodulating a received signal. | 04-03-2014 |
20140140454 | Coefficient-Specific Filtering of Initial Channel Estimates - Embodiments herein include a method of channel estimation in a wireless communication node. The method comprises generating, based on samples of a received signal, initial estimates of a plurality of channel coefficients forming a channel response. The method also entails, for each of the channel coefficients, dynamically calculating a coefficient-specific filter span for that channel coefficient. Notably, the coefficient-specific filter span for any given channel coefficient is calculated according to a closed-form function that minimizes aggregated estimation noise for the channel coefficient and estimation bias attributable to errors in tracking the channel coefficient. The method finally includes adapting filtering of the initial estimates independently for each of the channel coefficients to be performed over the coefficient-specific filter span calculated for that channel coefficient. | 05-22-2014 |
20140153499 | SIGNALING DATA CHANNEL'S CONFIGURATION INFORMATION TO FACILITATE INTERFERENCE CANCELLATION - In MU-MIMO scenarios, a target terminal can be exposed to data streams intended for other terminals. If the target terminal is capable of interference cancellation, then a network node, such as a base station or RNC, can provide the target terminal with interference information so that the target terminal can efficiently cancel interferences due to these interfering data streams. The interference information may include one or more interfering configuration, each of which characterizes a related interfering data stream. The interference information can also include the identity of the other terminal that is the intended recipient of the interfering stream. The network node may determine whether the target terminal can benefit from the interference information. If so, the network node can provide the interference information to the target terminal. | 06-05-2014 |
20140153678 | Estimating Optimal Linear Regression Filter Length for Channel Estimation - Techniques for obtaining smoothed channel response estimates in a communications receiver. An example method begins with obtaining ordered channel measurement samples for a current estimation interval and continues with the estimation of a short-term slope value for each of several sequential observation time intervals. A distortion metric is calculated for each of a plurality of candidate filter lengths, where each candidate filter length is an integer multiple of the uniform length. The distortion metric is based on the short-term slope values for observation time intervals falling within the candidate filter length, and characterizes the extent to which the candidate filter length will introduce tracking bias in subsequent signal processing. A filter length is then selected for use in demodulating a received signal from at least among the candidate filter lengths, based on the distortion metric values. | 06-05-2014 |
20140334579 | Method and Apparatus for Soft Symbol Generation in a Communication Receiver - A simplified but accurate soft-symbol determination process represents one of the advantages provided by the example embodiments disclosed herein. In this regard, a mapping function “maps” symbol estimates to corresponding soft symbol values, which may be used in interference mitigation, joint detection processing, etc. Whether the mapping function is implemented on-the-fly as a live calculation or is embodied in a look-up table, it advantageously operates on the symbol estimates directly, rather than requiring the derivation of corresponding soft bit values or the like, and it maps each symbol estimate to its “expected value,” i.e., the weighted sum of constellation point probabilities. Moreover, the mapping function may be changed dynamically—e.g., by using different look-up tables—to account for changing reception conditions and/or different modulation schemes or other signal parameters associated with the symbols being estimated and mapped to soft symbol values. | 11-13-2014 |
20140341260 | Robust, Fast Unused-Code Detection - Techniques for processing a received multi-code code-division multiple-access (CDMA) signal to detect unused spreading codes are disclosed. An example method includes, for each of a plurality of observation time intervals and for each of one or more candidate spreading codes, determining a detection threshold for use in detecting whether the candidate spreading code is unused in the received multi-code CDMA signal, based on a target detection sensitivity and at least one of an estimate of received signal quality and an estimate of channel estimation quality. Estimated signal power for the candidate spreading code is compared to estimated noise and interference power corresponding to a spreading code that is known to be unused or corresponding to a spreading code that carries known symbol values, using the calculated detection threshold. Whether or not the candidate spreading code is unused is then determined, based on the comparison. | 11-20-2014 |
20150029970 | Redundancy Version Selection Based on Receiving Quality and Transport Format - The embodiments herein relate to a method in a base station ( | 01-29-2015 |
20150078302 | System And Method For Providing And Using Radio Network Temporary Identifiers Signatures For Interference Cancellation - According to certain embodiments, methods and systems for providing device-specific radio network temporary identifiers (C-RNTI) signatures may be provided for interference cancellation. The methods and systems may include assigning a subset of C-RNTIs to a cell. A mapping may be defined between the subset of C-RNTI signatures and a set of C-RNTI indices. Each C-RNTI signature within the subset may be identifiable by a first wireless device via the mapping. The mapping between the subset of C-RNTI signatures and the set C-RNTI indices may be provided to the first wireless device. A C-RNTI indices indicating at least one currently scheduled wireless device may be provided to the first wireless device. | 03-19-2015 |