Abstract: Various embodiments relate to spread spectrum communication. A communication system may include a base station and a user equipment. The base station may be configured to: add a cyclic prefix (CP) to each block of a number of blocks of a first direct sequence spread spectrum (DSSS) signal to generate a first cyclic prefix-direct sequence spread spectrum (CP-DSSS) signal; add artificial noise to the first CP-DSSS signal; and transmit, via a channel, the first CP-DSSS signal. The user equipment configured to receive the first CP-DSSS signal. Associated methods and communications systems are also disclosed.

Abstract: A technology is described for moderating output confidence of output soft information associated with a MIMO detector. An example method can include generating output soft-information that is a measure of likelihood that a subset of bit sequence permutations correctly represents a bit sequence extracted from a radio signal received by the MIMO detector. Calculating a distance of the subset of bit sequence permutations to the bit sequence extracted from the radio signal. Determining that the output confidence of the output soft-information warrants adjustment of the output confidence of the output soft-information based in part on the distance of the bit sequence extracted from the radio signal to the subset of bit sequence permutations. And adjusting the output confidence of the output soft-information based in part on the distance of the bit sequence extracted from the radio signal to the subset of bit sequence permutations using an adjustment technique.

Abstract: A technology is disclosed and described for processing a radio signal using an excited Markov Chain Monte Carlo (MCMC) Gibbs sampler. An example method (200) may include calculating a distance (210) of a bit sequence from an estimated correct bit sequence, where the bit sequence may be extracted from a received radio signal received by a Multiple-Input and Multiple-Output (MIMO) detector. An excitation factor may be modified (220) based in part on the distance of the bit sequence from the estimated correct bit sequence, where the where the excitation factor may be used in part to calculate a probability of state transition of the bit sequence. A pseudo-convergence of the probability of state transition of the bit sequence may be detected (230) and a pseudo-convergence mitigation technique may be executed (240) that causes the probability of state transition of the bit sequence to increase.

Abstract: A multi-user network including a plurality of individual terminals, wherein each individual terminal includes a terminal receiver/transmitter, and a base station including a plurality of base station receiver/transmitters, wherein the number of base station receiver/transmitters is greater than the number of individual terminals. The base station is configured to communicate simultaneously with the plurality of individual terminals over a plurality of channels, filter the signal components, and combine the signal components. The plurality of channels each include a signal component. Each channel corresponds to an individual terminal. Combining the plurality of signal components results in a substantially flat gain.

Abstract: Log likelihood ratios for data bits transmitted in a multi-dimensional signal are estimated using multiple Markov chain Monte Carlo simulations (MCMC). The MCMC simulations can include constraining symbols based on a most-likely symbol to improve the likelihood of finding distances for non-most-likely symbols. The log likelihood ratios can be calculated based on distances of the most-likely symbol and the non-most-likely symbols.

Abstract: A technique for estimating channel data probability in a multi-user or multiple-input multiple-output communication system is disclosed. The technique uses parallel Markov Chain Monte Carlo simulation to select a plurality of hypothetical channel data patterns. Channel data bit probabilities are obtained by summing conditional bit probabilities, where the conditional bit probabilities are conditioned on an observation of the multi-channel signal and the hypothetical channel data patterns.

Abstract: A detector and method for estimating channel data probability in a multi-user or multiple-input multiple-output communication system includes summing conditional bit probabilities conditioned on hypothetical channel data patterns over stochastically selected hypothetical channel data patterns. Various detailed hardware structures and circuits are also described.

Abstract: A multi-carrier spread spectrum (MC-SS) technique is disclosed which includes non-linearly modifying the sub-carriers in the receiver. A method (600) and receiver (200, 300) for processing an MC-SS signal, a transceiver for MC-SS communications (700), and an MC-SS radar (800) are describe.

Abstract: A detector and method for estimating channel data probability in a multi-user or multiple-input multiple-output communication system includes summing conditional bit probabilities conditioned on hypothetical channel data patterns over stochastically selected hypothetical channel data patterns. Various detailed hardware structures and circuits are also described.

Abstract: A detector and method for estimating channel data probability in a multi-user or multiple-input multiple-output communication system includes summing conditional bit probabilities conditioned on hypothetical channel data patterns over stochastically selected hypothetical channel data patterns. Various detailed hardware structures and circuits are also described.

Abstract: Log likelihood ratios for data bits transmitted in a multi-dimensional signal are estimated using multiple Markov chain Monte Carlo simulations (MCMC). The MCMC simulations can include constraining symbols based on a most-likely symbol to improve the likelihood of finding distances for non-most-likely symbols. The log likelihood ratios can be calculated based on distances of the most-likely symbol and the non-most-likely symbols.

Abstract: A multicarrier spread spectrum (MC-SS) technique is disclosed which includes non-linearly modifying the sub-carriers in the receiver. A method (600) and receiver (200, 300) for processing an MC-SS signal, a transceiver for MC-SS communications (700), and an MC-SS radar (800) are describe.

Abstract: A detector and method for estimating channel data probability in a multi-user or multiple-input multiple-output communication system includes summing conditional bit probabilities conditioned on hypothetical channel data patterns over stochastically selected hypothetical channel data patterns. Various detailed hardware structures and circuits are also described.

Abstract: A method and system for canceling echo signals originating from a transmitter at a predetermined data rate. The echo signals are received by a receiver at a different data rate. The echo system is configured to manipulate data rates of transmitted signals, and reconstruct echo signals for consideration by the receiver. In view of the band-limited nature of these echo signals, the invention intelligently reduces the computational complexity of reconstructing and canceling echo signals.

Abstract: An acoustic echo canceller (AEC) is devised and tested in a real environment. The devised AEC puts together a number of available digital signal processing methods to make a real-time implementation of the AEC possible. The echo length coverage of the devised AEC can be as large as several hundred milliseconds. The devised AEC is based on a frequency domain implementation of the least-mean square (LMS) determination method. The fast Fourier transforms required for the implementation have been carefully selected and optimized so that a realtime implementation of the AEC is possible. In addition, two novel techniques are invented and added to the AEC to overcome two annoying serious problems commonly encountered in AEC systems. The first technique is a special howling suppressor which can successfully prevent the oscillation of the AEC under all possible practical conditions. The second proposed technique is a very simple, but yet very effective, double-talk detector.

Abstract: A method of designing an equalizer having a target response suited to a particular subclass of communication channels to shorten the duration of the impulse response of the overall transmission system, a class of channels being divided into a number of subclasses, each subclass having a fixed set of parameters selected to achieve the target response of the equalizer for that particular subclass of channel, the method comprising the steps of recognizing the subclass of the channel; and identifying the fixed set of parameters for the equaliser to achieve the target response by reference to a look-up table based on the subclass of the channel.