L-3 Communications Corporation

L3harris Technologies, Inc.

Future Wei Technologies, Inc.

University of Alberta

L3 Corrections Corporation

Christian B Schlegel

Thomas R Giallorenzi

Zachary C Bagley

L Andrew Gibson

Samuel Charles Kingston

David G Landon

June Y Sun

Michael Rice

Alexander Kimani

Young Hoon Kwon

Tao Wu

Carmela Cozzo

Eric K Hall

Richard B Ertel

Anthony Charles Rapley

David M Arnesen

Bruce F Cockburn

Yajun Kou

Lance R Lindsay

Stephen Bates

Christopher L Brown

Vincent Gaudet

Robert Hang

Chris J Winstead

Paul Andrew Goud

Sheryl Howard

Systems and methods for mitigating the effect of in-band interference. The methods comprise: receiving a signal comprising at least one interfering signal component; generating a soft value for each symbol in at least one interfering signal component; and using the soft values to cancel at least one interfering signal component from the signal to mitigate the effect of interference. The soft value represents a most likely value for the symbol which is obtained by: determining a probability metric between an actual value of the symbol and each of a plurality of possible symbol values using a scaling value representing an estimate of the noise level in the signal received by the device; generating current local probabilities for the plurality of possible symbol values using the probability metric; and using the current local probabilities to determine the soft value.

System and method implementing soft-decision based excision cancellation technology

A multipoint relay (MPR) wireless network may include spaced apart nodes, with each node including wireless transceiver circuitry, beacon circuitry, and a controller coupled to the wireless transceiver circuitry and beacon circuitry. The controllers may be configured to operate the beacon circuitry to determine a respective link strength metric for each potential link between nodes, assign a set of nodes from among the plurality of nodes to function as gateway nodes and assign other individual nodes to communicate via respective gateway nodes based upon the respective link strength metrics to define the MPR network so that one-hop links have a strongest link strength metric, and operate the wireless transceiver circuitry for communications over the MPR network.

Multipoint relay (MPR) network and related methods

Systems and methods for mitigating an effect interference. The methods comprise: receiving, by a device, a signal comprising a plurality of signal components; determining whether each signal component has a sufficient reconstructability; reconstructing each said signal component that was determined to have sufficient reconstructability using the received signal or an at least partially clean signal with other signal component(s) removed from the received signal; and using the reconstructed signal components to generate a modified received comprising the received signal with the signal components removed therefrom that (i) are devoid of a signal of interest and (ii) have sufficient reconstructability.

System and method implementing excision cancellation technology

A Radio Frequency (RF) receiver may include a lower-order phase shift keying (PSK) demodulation circuit configured to generate at least one locking parameter when performing a lower-order PSK demodulation of an RF receive signal having an interfering PSK signal component. A higher-order PSK demodulation circuit has a higher order than the lower-order PSK demodulation circuit, and locks to the RF receive signal using the at least one locking parameter from the lower-order PSK demodulation circuit. The higher-order PSK demodulation circuit performs the higher-order PSK demodulation of the RF receive signal based upon locking to the RF receive signal to determine the interfering PSK signal component.

Radio frequency (RF) receiver that determines an interfering phase shift keying (PSK) signal and associated methods

A system and method for iteration scheduling in joint equalization and turbo decoding are provided. A method for processing received information includes cancelling interference in a received signal bearing received information, decoding the interference cancelled received signal to produce information, and processing the received information. The cancelling comprises an iterative processing of the received signal based on soft information produced by a decoding the received signal.

System and method for iteration scheduling in joint equalization and turbo decoding

A system and method for signaling and detecting in wireless communications systems are provided. A method for processing information includes operating in a first phase, operating in a second phase, and processing the detected information. The first phase includes iteratively inverting a first filtering operation on received signals, and the second phase includes iteratively inverting a second filtering operation on received signals with consideration given to a first estimation error of symbols of the first user and a second estimation error of symbols of the second user.

System and method for signaling and detecting in wireless communications systems

A method and apparatus for mitigating multi-user interference in reception of a code division multiple access (CDMA) signal is described. The CDMA signal has a plurality of spread user symbol streams, each spread by a corresponding one of a plurality of spreading codes. Estimated symbols are iteratively improved by forming a reconstructed signal from the estimated symbols, subtracting the reconstructed signal from the CDMA signal to create a difference signal, and adjusting the estimated symbols based on a combination of the difference signal and the estimated symbols.

Method and device for mitigation of multi-user interference in code division multiple access

An architecture and a method are provided for decoding codewords for codes such as low density parity check (LDPC) codes. An iterative decoding algorithm such as the Belief Propagation Algorithm (BPA) is employed that attempts to correct errors in an input block of symbols via a structure containing two sets of nodes through node processing and the passing of messages between nodes. Message passing and node processing is performed in a digit-serial manner instead of a bit-parallel manner.

Method and apparatus for digit-serial communications for iterative digital processing algorithms

A method for acquiring signals received from multiple users in a single burst groups signals by power and sequentially processes the signal groups. A received sum of a plurality of user signals received in a burst is stored, and the transmitted symbols for each signal within a first group of the stored signals is estimated. A modified set of signals is then determined that excludes the signals of the first group. From the modified set of signals, the method continues by canceling multiuser interference among signals within a second group, and estimating transmitted symbols for each signal within the second group. The first and second groups includes all signals within a power band that defines the group, and the first band represents a higher power band than the second. Such iterative processing may continue for sequentially lower power bands until all signals are processed. A receiver is also detailed.

Multi-user receiver and method for successive acquisition

Communication of data over a multiple-input multiple-output (MIMO) channel includes allocating transmission power unequally to the different data streams. The transmission power allocation is performed without regard to a state of a changing channel response of the MIMO channel. A relatively low complexity interference cancelling receiver can therefore decode the data streams.

MIMO communication using interference cancellation and unequal transmit power distribution

Disclosed is a method for acquiring a user signal from among several received from multiple users in a single burst. The method includes receiving a plurality of user signals in a single transmission burst, suppressing multiuser interference among at least some of the plurality of received signals, and determining a carrier frequency of at least one signal from among the interference suppressed plurality of received signals. Said signals may rotate due to a lack of synchronization while being equalized. Also described is a multiuser receiver for acquiring at least one user signal from among several user signals received from multiple users in a single burst. An antenna is for receiving a plurality of user signals in a single spread spectrum transmission burst, a matched filter is for despreading the signals, a multiuser equalizer is for suppressing mutual interference among at least a portion of the plurality of user signals, and a carrier lock circuit is for determining a carrier frequency of at least one user signal of the portion.

Non-coherent multiuser receiver and method for aiding carrier acquisition in a spread spectrum system

A receiver () for performing timing recovery over at least one complex channel at low or less than zero SNR (signal power to noise power, in dB) has at least one receive element such as an antenna, an analog-to-digital converter(ADC), a fractional interpolation filter, a matched filter, and a timing correction loop. The timing correction loopselects a minimum mean square error from the output of the matched filterto determine a timing signal output to the interpolation filter, and provides one-bit weights to the matched filter. Preferably, the timing correction loopincludes a magnitude detector, a moving average filter, and a timing error detectorthat outputs an integer m and fractional &#x3bc; timing factor to the interpolation filter. Within a phase correction loopis a maximum likelihood channel estimatorand a phase error detectorthat controls a phase rotatordisposed between the ADCand the interpolation filter

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Low-voltage CMOS (Complementary Metal Oxide Semiconductor) circuits, suitable for analog decoders, for example, are provided. The circuits include multiplier modules that receive first input signals and respective ones of a plurality of second input signals. Each multiplier module generates as output signals products of the first input signals and its respective second input signals. Dummy multiplier modules that respectively correspond to the multiplier modules receive the second input signals, and each dummy multiplier module forms products of the second input signal of its corresponding multiplier module and the other second input signals. The dummy multiplier modules reduce the overall voltage requirements of the circuit, thereby providing for low-voltage operation. In some embodiments, a connectivity module receives output signals from the multiplier modules and generates as output signals sums of predetermined ones of the output signals, and a renormalization module receives and normalizes the output signals from the connectivity module to generate output signals that sum to a predetermined unit value.

Low-voltage CMOS circuits for analog decoders

A method is disclosed for operating a synchronous space division multiple access, code division multiple access communications system. The method includes steps of, within a coverage area of a base station (BS), (a) assigning the same spreading code to a plurality of subscriber stations (SSs); and (b) beamforming using an antenna array at the BS so as to maximize the signal to interference plus noise ratio for a signal transmitted from a desired SS, The beamforming operates to steer a null towards another same-code SS to minimize interference from the same-code SS. Assuming that the antenna array has M-elements (M&#x3e;1), then individual ones of P orthogonal spreading codes can be reused &#x3b1;M times within the coverage area, where 1/M&#x3c;&#x3b1;&#x2266;1. The step of beamforming includes an initial step of despreading the signal received from the desired SS, followed by a step of spatial filtering.

Growing community of inventors

Park City, UT, United States of America

Christian B Schlegel