Systems, apparatuses, and methods for enhancement for amplify-and-forward relay. Instead of merely passing received signal from a source, relay may equalize the received signal based on reference signal contained in the received signal, before amplifying and transmitting the signal to a destination. Compared to amplify-and-forward, equalize-and-forward may compensate the received source signal for various imperfections such as channel distortions and phase errors, using demodulation reference signal and phase tracking reference signal. The relay may apply Fast Fourier Transform (FFT) to equalize the signal in tone domain.

Methods, systems, and devices for wireless communications are described. A repeater may apply a frequency translation and a phase rotation adjustment to a transmitted signal to avoid radio frequency interference. For instance, wireless repeater may receive a signal from a first device on a first carrier frequency. The wireless repeater may identify one or more interfering signals affecting the reception or transmission of the signal. The wireless repeater may then perform a frequency translation from the first carrier frequency to the second carrier frequency, and may also apply a phase rotation adjustment corresponding to the frequency translation. The wireless repeater may retransmit the signal including the phase rotation adjustment over the second carrier frequency to a second device in the wireless network.

A receiver includes a continuous-time equalizer, a decision-feedback equalizer (DFE), data and error sampling logic, and an adaptation engine. The receiver corrects for inter-symbol interference (ISI) associated with the most recent data symbol (first post cursor ISI) by establishing appropriate equalization settings for the continuous-time equalizer based upon a measure of the first-post-cursor ISI.

A transceiver of a user equipment includes a receiving stage, a frontend channel estimator, a frontend channel equalizer, a backend channel estimator, and a backend channel equalizer. The receiving stage is configured to receive an inbound signal from a SUDAC, which enables a relay communication including a frontend communication using extremely-high frequencies and a backend communication using ultra-high frequencies. The inbound signal includes a data portion, a backend control portion and a frontend control portion, the frontend control portion including a frontend evaluation signal and a configuration signal. The frontend and the backend channel estimators are configured to perform channel estimations based on the frontend evaluation signal and the backend control portion, respectively, wherein the frontend and backend channel equalizers are configured to equalize distortions, caused by using the extremely-high and ultra-high frequencies, respectively, based on the channel estimation of the frontend and backend channel estimators, respectively.

A communications device comprising receiver circuitry, transmitter circuitry and controller circuitry controlling the transmitter circuitry and the receiver circuitry to receive data in accordance with an automatic repeat request (ARQ) type protocol in which the data is received as a plurality of encoded data packets encoded with an error correction code and the transmitter circuitry transmits a feedback signal depending on whether each of the data encoded packets is estimated as having been decoded successfully by the receiver circuitry. The controller circuitry is configured to evaluate a quality measure of each encoded data packet and in response to the evaluated quality measure to transmit an early indication of the feedback signal to the wireless communications network, before the encoded data packet has been decoded by the error correction decoder.

Systems and methods for canceling carrier frequency offset (CFO) and sampling frequency offset (SFO) in a radio receive chain are disclosed. In one embodiment, a method is disclosed, comprising: receiving a sub-frame via a radio receive chain in a time domain; performing per-user filtering on the sub-frame to obtain a signal for a particular user; obtaining a CFO correction signal; adding the CFO correction signal in the time domain to perform a CFO correction step on the signal for the particular user; performing an FFT on the output of the CFO correction step to obtain samples in a frequency domain; adding an SFO correction signal in the frequency domain to perform an SFO correction to the output of FFT step; and demodulating the output of SFO correction step, thereby performing CFO and SFO correction while reducing inter-carrier interference (ICI).

A random access memory (RAM) including a deserializer is disclosed. The RAM further comprises a continuous-time linear equalizer (CTLE) including a first input terminal that receives an input signal for the RAM and a first output terminal communicatively connected to the deserializer, the CTLE configured to perform a channel gain compensation on the input signal received by the first input terminal and to transmit the compensated input signal to the deserializer. The RAM may further comprise a decision feedback equalizer (DFE) including a second input terminal communicatively connected to the CTLE and a second output terminal communicatively connected to the deserializer, the DFE configured to reduce an inter-symbol interference (ISI) of the input signal.

Embodiments of the present disclosure provide a method, device, and computer readable medium for channel equalization. The method comprises receiving, at a first device, a first signal from a second device via a plurality of subcarriers over a communication channel; sampling the first signal to obtain sampled symbols; and generating a second signal based on the obtained sampled symbols using a direct association between sampled symbols and payloads, the second signal indicating a payload of the first signal carried on an effective subcarrier of the plurality of subcarriers. Through the use of the direct association between sampled symbols and payloads, it is possible to achieve channel equalization in a less complicated, more reliable, and cost-effective manner, so as to extract the payload in the received signal.

A method and structure for tap centering in a coherent optical receiver device. The center of gravity (CG) of the filter coefficients can be used to evaluate a proper convergence of a time-domain adaptive equalizer. However, the computation of CG in a dual-polarization optical coherent receiver is difficult when a frequency domain (FD) adaptive equalizer is adopted. In this case, the implementation of several inverse fast-Fourier transform (IFFT) stages is required to back time domain impulse response. Here, examples of the present invention estimate CG directly from the FD equalizer taps and compensate for an error of convergence based off of the estimated CG. This estimation method and associated device architecture is able to achieve an excellent tradeoff between accuracy and complexity.

A method and structure for signal propagation in a coherent optical receiver device. Asynchronous equalization helps to reduce complexity and power dissipation, and also improves the robustness of timing recovery. However, conventional devices using inverse interpolation filters ignore adaptation algorithms. The present invention provides for forward propagation and backward propagation. In the forward case, the filter input signal is forward propagated through a filter to the adaptation engine, while, in the backward case, the error signal is backward propagated through a filter to the asynchronous domain. Using such forward and backward propagation schemes reduces implementation complexity while providing optical device performance.