Abstract: Disclosed herein are a method and apparatus for iterative interference cancellation and channel estimation in a system based on FTN communication including a pilot. Interference of a pilot symbol on a data symbol is estimated, and the estimated interference is eliminated from a sequence of data symbols. When demodulation and channel decoding are performed on the sequence of data symbols, interference between data symbols and interference of a data symbol on a pilot symbol are estimated. Such estimation is repeatedly performed, and as FTN interference is repeatedly estimated and eliminated, channel estimation performance is improved, and through the improved channel estimation performance, the reception performance of the entire system is improved.

Abstract: This application discussed trajectory modification techniques for polar transmission architectures. In an example, a method can include receiving a first sample, determining an absolute phase angle change between the first sample and a third sample, and if the first angle change is greater than a threshold phase angle, adjusting phase information of a second sample to provide a modified second sample such that a trajectory associated with the first sample, the modified second sample and the third sample passes through an origin. In an example, the second sample can be received prior to receiving the first sample, and the third sample can be received prior to receiving the second sample.

Abstract: Aspects of the subject disclosure may include, for example, determining a target position of a particular physical location, accessing an image system that provides a number of images based on physical locations including the particular physical location, and obtaining a target image from the image system based on the particular physical location. The target image includes imaged features based on physical features of the particular physical location. Image processing is applied to the target image, and a particular physical feature is identified as a candidate deployment site based on the applying of the image processing, wherein the candidate deployment site is configured to accommodate equipment of a distributed communication network that facilitates transmission of electromagnetic waves along a surface of a transmission medium. Other embodiments are disclosed.

Abstract: A phase detection system includes first and second phase mixing circuits in signal communication with a signal phase adjuster module. The first mixing circuit generates a first digital modulated frequency signal based on an input signal and a first reference phase signal. The second mixing circuit generates a second digital modulated frequency signal based on the input signal and a second reference phase signal, which phase shifted with respect to the first reference phase signal. The phase detection system further includes a phase identification (ID) module in signal communication with the first mixing circuit and the second mixing circuit. The phase ID module generates a phase signal based on the first digital modulated frequency signal and the second digital modulated frequency signal. The phase signal indicates a phase of the input signal.

Abstract: A method for frequency- and time-selective interference suppression for a communication system based on OFDM, and a receiver therefor. To achieve a much lower bit error rate at the output of the receiver or to permit greater interference or a lower signal-to-noise ratio (in a prior art L-DACS1 receiver, at least 45 nautical miles) for the same transmission power, the invention provides: a filter bank pulse blanking method FBPB in which the sampled received signal is applied to a blanking unit for frequency-selective pulse blanking, which blanking unit consists of an analysis filter bank having M sub-bands; a module for frequency-selective pulse blanking of the sub-band signals; and a synthesis filter bank, which reassembles the signal. The analysis filter bank, which breaks down the received signal into multiple sub-bands on a frequency-selective basis, is used before OFDM windowing, such that the sub-band breakdown applies pulse blanking on a sub-band-selective basis.

Abstract: Apparatuses, methods, and systems for precoding multi-carrier signals are disclosed. One method includes obtaining a transmission channel matrix between a terminal and a plurality of separate users, wherein the transmission channel matrix includes channel estimates for a plurality of subcarriers of the multi-carrier signal. A channel dimension reduction matrix is determined based upon a composite of the channel estimates for the plurality of subcarriers, wherein dimensions of the channel dimension reduction matrix are less than dimensions of the transmission channel matrix. The method further includes determining a precoding matrix for the terminal based on the channel dimension reduction matrix, wherein the precoding matrix is multi-carrier signal independent, determining an effective channel based on a channel estimate of the transmission channel and based on the precoding matrix of the terminal, and determining a precoding matrix for the central processing unit based on the effective channel.

Abstract: The present disclosure provides system and methods for calibrating a tunable metamaterial device. A sequence of port impedance vectors, (z(m), m), may be generated. Each of the port impedance vectors may be applied to the tunable metamaterial device, and measuring at least one S-parameter. A simulated S-Matrix may be generated by associating each of the port impedance vectors, z(m), with the unknown admittance matrix. The unknown admittance matrix may be solved for by determining a plurality of optimization variables by comparing each of the S-parameters, S(m), to the simulated S-Matrix for each port impedance vector, z(m), and generating an estimated admittance matrix by associating each of the optimization variables with the unknown admittance parameters. The estimated admittance matrix may be used for more accurate radiation patterning.

Abstract: Multiplexing circuitry and method for driving multiplexing circuits are provided. A circuit includes a multiplexer circuit having symmetrical data input paths driven by a half-rate clock signal and a first stage multiplexing circuit configured to provide input signals to the multiplexer circuit. The first stage multiplexing circuit is driven by quadrature clocks to generate time-shifted data.

Abstract: A transmission and reception circuit includes a transmission circuit, a reception circuit, and a signal feedback path. The transmission path includes an output section, a signal generating circuit generating an in-phase component signal and an orthogonal component signal, and a transmission analog baseband circuit configured to perform digital to analog conversion of the generated in-phase component signal and orthogonal component signal. The reception circuit includes an input section, a reception analog baseband circuit performing analog to digital conversion of the transmitted in-phase component signal and orthogonal component signal, and a signal detection circuit that detects the analog-to-digital converted in-phase component signal and orthogonal component signal converted by the reception analog baseband circuit.