Abstract: In one aspect, the present disclosure provides an advantageous generalization of a SLIC receiver structure, by allowing multiple solutions to survive at any one or more of the serial stages included in the SLIC receiver. Where any given stage produces multiple solutions, the next stage of the SLIC receiver processes those multiple input solutions to produce multiple output solutions. Consequently, the contemplated SLIC receiver effectively builds a tree structure with as many levels as there are stages in the SLIC receiver. Such operations allow the SLIC receiver to form two or more solution threads spanning the stages, and to make an improved overall demodulation decision for a received symbol vector by selecting the best solution thread. Further, the additional complexity of allowing multiple survivor solutions at one or more SLIC stages is controlled in one or more embodiments, using survivor pruning for example.

Abstract: In one aspect, the present disclosure provides an advantageous generalization of a SLIC receiver structure, by allowing multiple solutions to survive at any one or more of the serial stages included in the SLIC receiver. Where any given stage produces multiple solutions, the next stage of the SLIC receiver processes those multiple input solutions to produce multiple output solutions. Consequently, the contemplated SLIC receiver effectively builds a tree structure with as many levels as there are stages in the SLIC receiver. Such operations allow the SLIC receiver to form two or more solution threads spanning the stages, and to make an improved overall demodulation decision for a received symbol vector by selecting the best solution thread. Further, the additional complexity of allowing multiple survivor solutions at one or more SLIC stages is controlled in one or more embodiments, using survivor pruning for example.

Abstract: The present disclosure provides an apparatus and method for advantageously simplifying joint detection processing in one or more demodulation stages of a multi-stage receiver by configuring at least one stage to use a constrained multi-user search, such as a constrained tree search. For example, a multi-stage receiver includes at least two stages configured to successively process a received composite signal that includes signal contributions from two or more “users”, which, for example, means that the received signal includes two or more symbol streams. In a non-limiting example, particular embodiments of the present invention combines constrained tree searching with Serial Localized Indecision (SLIC) processing in a multi-stage receiver, where each stage includes a joint processing unit. At least one of those stages is configured to use a constrained multi-user search, rather than a full search, for jointly detecting symbols in the stage input signal.

Abstract: A constellation processing module of a receiver groups points of a constellation associated with a transmitted signal into a plurality of subsets. At least two adjacent ones of the subsets have one or more common constellation points so that the at least two adjacent subsets overlap. The constellation processing module also determines a centroid-based value for each of the subsets of constellation points. A non-final equalization stage localizes a search for a final symbol decision using a set of the centroid-based values as constellation points. An interference suppresser suppresses residual self-interference which arises from using the set of centroid-based values as constellation points to localize the search for the final symbol decision instead of the constellation points used to modulate the transmitted signal. A final equalization stage determines the final symbol decision using a subset of the constellation points used to modulate the transmitted signal.

Abstract: A receiver for a mobile communication device comprises an primary detector for generating an initial sequence estimate comprising a plurality of initial symbol estimates from a received symbol sequence corrupted by intersymbol interference, and a secondary detector to receive said initial sequence estimate and to output a final sequence estimate comprising a plurality of final symbol estimates. The secondary detector comprises a sequence generator configured to generate one or more revised sequence estimates by replacing at least one initial symbol estimate in said initial sequence estimate with a corresponding nearest neighbor symbol in each of said revised symbol estimates; an error calculator to compute error metrics for said revised sequence estimates; and a selection circuit to compare error metrics for said initial and revised sequence estimates and to output one of said initial or revised sequence estimates as said final sequence estimate based on said error metrics.

Abstract: The present disclosure provides an apparatus and method for advantageously simplifying joint detection processing in one or more demodulation stages of a multi-stage receiver by configuring at least one stage to use a constrained multi-user search, such as a constrained tree search. For example, a multi-stage receiver includes at least two stages configured to successively process a received composite signal that includes signal contributions from two or more “users”, which, for example, means that the received signal includes two or more symbol streams. In a non-limiting example, particular embodiments of the present invention combines constrained tree searching with Serial Localized Indecision (SLIC) processing in a multi-stage receiver, where each stage includes a joint processing unit. At least one of those stages is configured to use a constrained multi-user search, rather than a full search, for jointly detecting symbols in the stage input signal.

Abstract: Probability information generated by a decoder as part of the symbol decoding process is fed back for use by a multi-stage demodulator that employs serial localization with indecision so that the accuracy of the final symbol decision generated by the multi-stage demodulator is improved. The multi-stage demodulator has one or more non-final stages operable to localize a search for the final symbol decision of a received signal using centroid-based values as constellation points instead of modulation symbols associated with the received signal. A final stage of the multi-stage demodulator is operable to determine the final symbol decision using a subset of the modulation symbols as constellation points. The decoder is operable to decode the final symbol decision, including generating probability information related to the modulation symbols. The multi-stage demodulator is operable to revise the final symbol decision based on the probability information related to the modulation symbols.

Abstract: A receiver and method are described herein that address inter-symbol interference in a received signal by using a two-stage equalizer which includes a first demodulation stage that processes the received signal and produces initial symbol decisions, and a non-linear equalization second stage that uses the received signal to perform a sequential search in an attempt to improve upon the initial symbol decisions where if able to improve upon the initial symbol decisions then an output sequence is obtained from the sequential search and if not able to improve upon the sequence metric threshold then the output sequence is the initial symbol decisions.

Abstract: Probability information generated by a decoder as part of the symbol decoding process is fed back for use by a multi-stage demodulator that employs serial localization with indecision so that the accuracy of the final symbol decision generated by the multi-stage demodulator is improved. The multi-stage demodulator has one or more non-final stages operable to localize a search for the final symbol decision of a received signal using centroid-based values as constellation points instead of modulation symbols associated with the received signal. A final stage of the multi-stage demodulator is operable to determine the final symbol decision using a subset of the modulation symbols as constellation points. The decoder is operable to decode the final symbol decision, including generating probability information related to the modulation symbols. The multi-stage demodulator is operable to revise the final symbol decision based on the probability information related to the modulation symbols.

Abstract: A wireless communication device includes at least two antennas with at least two corresponding receive chains. Selectively activating and deactivating the receivers as needed for a desired quality of reception controls the performance and power consumption of the wireless communication device. The wireless communication device may operate in a single receiver mode or a dual receiver diversity mode. In the dual receiver diversity mode, the wireless communication device may selectively control the gain of one or more antennas and/or reconfigure one or more receive chains to minimize power consumption while maintaining a desired performance.

Abstract: A receiver for a mobile communication device comprises an primary detector for generating an initial sequence estimate comprising a plurality of initial symbol estimates from a received symbol sequence corrupted by intersymbol interference, and a secondary detector to receive said initial sequence estimate and to output a final sequence estimate comprising a plurality of final symbol estimates. The secondary detector comprises a sequence generator configured to generate one or more revised sequence estimates by replacing at least one initial symbol estimate in said initial sequence estimate with a corresponding nearest neighbor symbol in each of said revised symbol estimates; an error calculator to compute error metrics for said revised sequence estimates; and a selection circuit to compare error metrics for said initial and revised sequence estimates and to output one of said initial or revised sequence estimates as said final sequence estimate based on said error metrics.

Abstract: A constellation processing module of a receiver groups points of a constellation associated with a transmitted signal into a plurality of subsets. At least two adjacent ones of the subsets have one or more common constellation points so that the at least two adjacent subsets overlap. The constellation processing module also determines a centroid-based value for each of the subsets of constellation points. A non-final equalization stage localizes a search for a final symbol decision using a set of the centroid-based values as constellation points. An interference suppresser suppresses residual self-interference which arises from using the set of centroid-based values as constellation points to localize the search for the final symbol decision instead of the constellation points used to modulate the transmitted signal. A final equalization stage determines the final symbol decision using a subset of the constellation points used to modulate the transmitted signal.

Abstract: A receiver and method are described herein that address inter-symbol interference in a received signal by using a two-stage equalizer which includes a first demodulation stage that processes the received signal and produces initial symbol decisions, and a non-linear equalization second stage that uses the received signal to perform a sequential search in an attempt to improve upon the initial symbol decisions where if able to improve upon the initial symbol decisions then an output sequence is obtained from the sequential search and if not able to improve upon the sequence metric threshold then the output sequence is the initial symbol decisions.

Abstract: A spread spectrum signal is processed by correlating the spread spectrum signal with a spreading sequence at a first plurality of correlation times to produce a first plurality of time-offset correlations. The first plurality of time-offset correlations is processed to produce a first symbol representation for a symbol. A first quality is determined for the first symbol representation. Responsive to the determined first quality, it is determined whether to further process the first symbol representation or to process a second symbol representation for the symbol generated from the spread spectrum signal. The first quality may be determined, for example, by decoding the first symbol representations to generate a decoding metric or error check indicator, such as a CRC result. The symbol representations may be generated and/or evaluated for quality in a serial fashion or a parallel fashion.

Abstract: A flexible Fast Walsh Transform circuit provides configurable FWT sizes, and is suitable for use in radio receivers where the received signal may be generated using varying spreading codes and/or varying numbers of multi-codes. Such signal types are commonly encountered in wireless communication systems like those based on the Wideband CDMA (W-CDMA) or IS-2000 (cdma2000) standards, and particularly with the higher data rate provisions of those standards. In one application, a RAKE receiver includes RAKE fingers that each include one of the flexible FWT circuits, such that each finger despreads the received signal using variably sized FWTs in accordance with the characteristics of the received signal. The flexibility in FWT sizing may derive from, for example, the inclusion of separately selectable but differently sized FWT circuits, or from the inclusion of a configurable FWT circuit capable of generating different sizes of FWTs.

Abstract: According to a method and apparatus taught herein, a decoding circuit and method decode linear block codes based on determining joint probabilities for one or more related subsets of bits in received data blocks. The use of joint probabilities enables faster and more reliable determination of received bits, meaning that, for example, joint probability decoding requires fewer decoding iterations than a comparable decoding process based on single-bit probabilities. As a non-limiting example, the decoding circuit and method taught herein provide advantageous operation with Low Density Parity Check (LDPC) codes, and can be incorporated in a variety of communication systems and devices, such as those associated with wireless communication networks.

Abstract: A system and method for adapting a broadcast service in a cellular communication network. A base station receives indications of channel quality from registered users of the broadcast service, and adapts broadcast transmission parameters to improve channel quality for the broadcast users if at least one of the broadcast users indicates that channel quality needs to be improved. If none of the broadcast users indicates that channel quality needs to be improved, the base station adapts the transmission parameters to decrease channel quality for the broadcast users. The transmission parameters may be adapted by techniques such as changing the broadcast transmit power, changing the level of FEC encoding and modulation, changing the number of channel resources allocated, or changing the transmission data rate for the broadcast service.

Abstract: A front-end architecture and processing method for a receiver in a multi-antenna, multi-band radio. Band-dependent components for multiple frequency bands are not duplicated in each receive chain. In one embodiment, a first receive chain includes band-dependent components for the first frequency band only. A second receive chain includes band-dependent components for the second frequency band only. The receive chains may be dedicated to particular antennas, or a switch may be utilized to route signals from different antennas to the different band-dependent components. Each receive chain may include band-independent components, or a single set of band-independent components may be utilized for the different receive chains by multiplexing the output of the band-dependent component sections.

Abstract: A CDMA communication system uses a set of quasi-orthogonal codes to supplement the standard set of Walsh codes used in conventional systems. Users are assigned a code selected from the set of Walsh codes, if available. If the number of users exceeds the number of available Walsh codes, selected users are assigned to quasi-orthogonal codes. The users assigned quasi-orthogonal codes are chosen based on user mobility.

Abstract: A method and apparatus in a radio receiver for canceling interference from a high power, high data rate signal received in a combined signal that includes a contribution from the high power signal and a contribution from a lower power signal. It is first determined whether the high power signal was correctly received. A CRC checksum may be used to determine whether the high power signal was received with a good reliability. Thereafter, the contribution of the high power signal is removed from the received signal only if the high power signal was correctly received. The contribution of the high power signal may be removed by hard-subtracting the contribution of the high power signal from the received signal if all of the bits of the checksum are correct, and soft-subtracting the contribution of the high power signal from the received signal if most, but not all, of the bits in the checksum are correct.