| Patent application number | Description | Published |
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| 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 K| 01-13-2011 | |
