Abstract: A high speed add-compare-select (ACS) circuit for a Viterbi decoder or a turbo decoder has a lower critical path delay than that achievable using a traditional ACS circuit. According to one embodiment of the invention, the path and branch metrics are split into most-significant and least-significant portions, such portions separately added in order to reduce the propagation delay.

Abstract: A resynchronization method for use in a data communication system having a first device configured to transmit data at a symbol rate to a second device. The second device includes a Reed Solomon (RS) decoder having a RS lock indicator and a Moving Picture Experts Group (MPEG) Protocol Interface (MPI) having a MPI lock indicator, wherein the RS and MPI lock indicators are monitored. Four different states, defined by the values of the RS and MPI lock indicators, determine whether the data communication system will wait for the RS decoded and the MPI hardware block to resynchronize, whether an intermediate-subset of the channel acquisition algorithm is performed or whether the entire channel acquisition algorithm is performed. The method of resynchronization described herein recovers synchronization within a predetermined time without the layers above the physical link layer having knowledge.

Abstract: A system for synchronizing a wireless receiver is provided. The system includes a first antenna and a second antenna to receive independent wireless signals containing different combination of data packets. The system includes one or more analyzer components operable to determine correlation metrics based on at least a portion of the first received signal and a portion of the second received signal. The system further includes a synchronization component operable to use the correlation metrics to determine a preferred correlation metric for synchronization by the wireless receiver of the first and second received signals to decode the data packet. A method for synchronizing a receiver of two wireless signals is also provided.

Abstract: A system for synchronizing a wireless receiver is provided. The system includes a first antenna (101a) and a second antenna (101b) to receive wireless signals containing data packets. The system includes one or more analyzer components (156) operable to determine correlation metrics based on at least a portion of the first received signal and a portion of the second received signal. The system further includes a synchronization component (158) operable to use the correlation metrics to determine a preferred correlation metric for synchronization by the wireless receiver of the first and second received signals to decode the data packet. A method for synchronizing a receiver of two wireless signals is also provided.

Abstract: A system and process that are a hybrid of distillation and membrane separations offers a highly efficient means of separating a fluid feed mixture into organic, solid, and aqueous components. The distillation section is followed by two membrane separation sections operated in parallel, with the distillation section separating the feed mixture into an organics-rich fraction and an organics-depleted and solids-rich fraction. One membrane section operates on the organics-rich fraction and separates it into a more organics-rich sub-fraction and a water-rich, organics-depleted sub-fraction, while the other membrane section operates on the organics-depleted, solids-rich fraction from the distillation section and separates it into a solids-rich sub-fraction and a solids-depleted, water-rich sub-fraction.

Abstract: In some embodiments, a device includes a multiple-input multiple-output (“MIMO”) decoder module coupled to a first log-likelihood-ratio (“LLR”) computing unit. The decoder module includes at least one processing unit and at least one sorting unit. The decoder module preferably uses a K-best breadth-first search method to decode data from MIMO sources. In some embodiments, a method includes receiving data representing a vector of receive signal samples detected by multiple receive transceivers. The method further includes performing a K-best breadth-first search on the data to obtain an estimated constellation point. The method further includes providing a user data stream based at least in part on the estimated constellation point.

Abstract: The problem outlined above may at least in part be addressed by N-Candidate Depth-First Decoding methods and systems that employ such methods. In some embodiments, the method includes receiving data representing a vector of receive signals detected by multiple receive transceivers; performing an N-candidate, depth-first search on the data to obtain an estimated constellation point; and providing a user data stream based at least in part on the estimated constellation point. In some embodiments the system includes a multiple-input multiple-output decoder. The decoder is configured to perform an N-candidate, depth-first search as part of converting a receive signal into a data stream.

Abstract: The equivalence of two or more constraint files of an integrated circuit (IC) design are checked. The comparison is performed between files at the same stage of design, files that correspond to different stages of the design flow, or between top-level and block-level constraint files.

Abstract: The present invention provides a gain training generator for use with a multiple-input, multiple-output (MIMO) transmitter employing N transmit antennas where N is at least two. In one embodiment, the gain training generator includes a fundamental training encoder configured to provide a basic gain training sequence to one of the N transmit antennas during a time interval to produce a basic gain training waveform having a basic peak-to-average ratio (PAR). Additionally, the gain training generator also includes a supplemental training encoder coupled to the fundamental training encoder and configured to further provide (N?1) supplemental gain training sequences to (N?1) remaining transmit antennas, respectively, during the time interval to produce supplemental gain training waveforms wherein each has a supplemental PAR substantially equal to the basic PAR.

Abstract: A preamble frequency switching design technique for frequency switching the training symbols within the preamble associated with a MIMO communication system ensures that data throughput is optimized.

Abstract: The present invention provides a concurrent gain generator for use with a MIMO transmitter havi'ng an N of two or more transmit antennas. In one embodiment, the concurrent gain generator includes a first sequence formatter that provides one of the N transmit antennas with a gain training sequence during an initial time interval, and a second sequence formatter that further provides (N?1) remaining transmit antennas with (N?1) additional gain training sequences during the initial time interval to train receive gains. The present invention also provides a non-concurrent gain adjuster for use with a MIMO receiver employing an M of two or more receive antennas. In one embodiment, the non-concurrent gain adjuster includes a gain combiner that computes a common receive gain as a function of M independent receive gains, and a gain applier that applies the common receive gain to receivers associated with the M receive antennas.

Abstract: In a wireless MIMO system with interference cancellation, compensate for decision errors in the cancelled symbols by adjustments to the scaling of the soft estimates with additive interference-proportional to estimates of the decision error probability.

Abstract: A branch metric duplication method substantially reduces interconnection delays. The branch metric duplication method is particularly useful to implement a high speed radix-4 Viterbi decoder targeted for FPGA applications. The decoder includes a plurality of branch metric computation units (BMCUs), at least one add-compare-select unit (ACSU) having a plurality of cells, and a survivor path memory unit (SMU). The plurality of BMCUs, the at least one ACSU, and the SMU are configured to implement the decoder.

Abstract: A Hybrid IMMSE-LMMSE receiver processing technique predicts performance of and selects between iterative and non-iterative decoding of symbols based on an intelligent metric. Based on a pre-specified criterion, the receiver determines if a correct first-stage decision is made or not. If a correct decision is made, then it follows iterative processing like in BLAST. Alternatively, if a wrong decision is found to have occurred, the receiver resorts to LMMSE estimation processing.

Abstract: A method and systems for reducing the complexity of a parity checker are described herein. In at least some preferred embodiments, a parity-check decoder includes column store units and one or more alignment units, which are coupled to the column store units. The column store units outnumber the alignments units.

Abstract: An electronic circuit (300) includes a signal processing circuit (310) including first and second signal processing blocks (310.1, 310.3) coupled in cascade, a memory circuit (320) coupled to and adjustable between the first and second signal processing blocks (310.1, 310.3), the memory circuit (320) having memory spaces, the memory circuit (320) configurable to establish a trade-off of the memory spaces between the first and second signal processing blocks (310.1, 310.3), and a configuring circuit (330) operable to configure the trade-off of the memory spaces of the memory circuit (320).

Abstract: A methods and apparatus for synchronizing a de-interleaver are disclosed. One example method includes fixing a phase of a de-interleaver in a first state; de-interleaving symbols in the signal while the phase of the de-interleaver is in the first state; processing the de-interleaved symbols; detecting if the known information is present in the processed de-interleaved symbols; and switching the phase of the de-interleaver between the first state and a second state when the known information is detected in the processed de-interleaved symbols.

Abstract: A Viterbi decoder includes a branch metric unit for generating branch metrics between two states at two different time periods, a traceback unit, a traceback memory and an add-compare-select circuit. The add-compare-select circuit includes a plurality of cascaded add-compare-select sub-circuits, each add-compare-select sub-circuit calculating a path metric responsive to a plurality of branch metrics from the branch metric unit and a plurality of pre-calculated path metrics, where at least one of the add-compare-select sub-circuits receives a set of pre-calculated path metrics from another one of the add-compare-select sub-circuits.

Abstract: A resynchronization method for use in a data communication system having a first device configured to transmit data at a symbol rate to a second device. The second device includes a Reed Solomon (RS) decoder having a RS lock indicator and a Moving Picture Experts Group (MPEG) Protocol Interface (MPI) having a MPI lock indicator, wherein the RS and MPI lock indicators are monitored. Four different states, defined by the values of the RS and MPI lock indicators, determine whether the data communication system will wait for the RS decoded and the MPI hardware block to resynchronize, whether an intermediate-subset of the channel acquisition algorithm is performed or whether the entire channel acquisition algorithm is performed. The method of resynchronization described herein recovers synchronization within a predetermined time without the layers above the physical link layer having knowledge.

Abstract: A method of correctly estimating the frequency offset when the CPE modem has already acquired and is tracking the OFDM burst boundaries in an OFDM-based, wireless communication system. CPS data in an OFDM-based, wireless communication system is modulated as QPSK data in the training tones of the data burst. As long as some bursts have the CPS data modulation and some bursts do not have the CPS data modulation, the CPS data can be recovered. A slip results when there is a linear phase difference across the tones (after the FFT) between the current and the previous burst. This linear phase difference is generally taken care of by the channel estimation obtained using the pilot tones. This phase difference is however, now compensated for correct frequency offset estimation which occurs before the channel estimation and CPS decoding steps.