Methods and systems for obtaining improved joint channel estimates for a multi-user, frequency-multiplexed data transmission such as SC-FDMA or OFDM begins by estimating separate contributions of users (and/or other signal sources) to the received signal based on joint frequency domain channel estimates. A reduced data set is obtained by subtracting contributions of one or more users from the received data, leaving only the estimated contributions of the remaining users, with noise and residual estimation error signal. Time domain joint channel estimation is then performed on the reduced data set, which is feasible because the number of users has been reduced. In exemplary embodiments, the reduced data set includes only one estimated user contribution. This process is repeated to obtain time domain estimates for all of the users. The method can be repeated by using the TD channel estimates to re-estimate the user contributions and calculate revised TD channel estimates.

Embodiments of the present disclosure provide a method and apparatus for determining a nonlinear characteristic and a system. The method for determining a nonlinear characteristic includes: determining a correction factor of a nonlinear item of a nonlinear model of a system to be measured according to an input and/or a parameter of the system to be measured; correcting the nonlinear item of a nonlinear model of the system to be measured by using the correction factor; and obtaining a nonlinear characteristic of the system to be measured according to the corrected nonlinear model. The nonlinear characteristic allows the input and/or the parameter of the system to be corrected to produce a corrected output. With the embodiments of the present disclosure, the nonlinear characteristic of the system to be measured under different inputs and/or parameters may be estimated, and accuracy of the estimation and applicability are improved.

A downlink channel estimation method based on a co-prime array in asymmetric massive MIMO architecture is provided. First, an uplink and downlink asymmetric receiving and transmitting system model based on a co-prime array is established, and a deviation of the frequency domain direction caused by array broadband signals is observed; then, uplink receiving is performed to estimate an uplink channel, and channel parameters such as the number of paths, the angle of arrival and the path gain are recovered; and finally, a downlink channel is reconstructed based on the channel parameters recovered according to the uplink channel. By means of the high angular resolution of the co-prime array, the problem that a recovered uplink channel cannot be directly used for pre-coding of a downlink channel is solved.

Methods, systems, and devices that support channel estimation reference signals for pre-equalization are described. In some examples, channel state information (CSI) for a link between a user equipment (UE) and another wireless device may be acquired by the UE based on samples of a downlink reference signal transmitted from the UE to the wireless device. Specifically, the wireless device (e.g., an extended reality (XR) device) may obtain samples of the downlink reference signal (e.g., a channel estimation reference signal) and report or indicate (e.g., transmit) the samples to the UE via an uplink transmission. For example, the reference signals may be sampled at the wireless device side, and CSI may be obtained using the samples signaled back to the UE by the wireless device. The UE may perform channel estimation based on the received samples, which may enable transmit pre-equalization of signals sent to the wireless device.

A communications device for Multi-Tone Mask (MTM) mode communications at a first router on a powerline communications (PLC) channel in a PLC network including a subnetwork including at least said first router associated with a plurality of nodes, comprising. A memory which stores a broadcast transmission MTM (BT-MTM) communications algorithm. A modem with processor is coupled to the memory. The processor is programmed to implement said BT-MTM communications algorithm, said BT-MTM communications algorithm.

An apparatus and a method of channel estimation and equalization based on pilot signals, which acquire a channel estimation vector and effectively perform channel equalization by using scattered pilots and continuous pilots in a communication system to which an OFDM symbol is applied, such as a DOCSIS 3.1 Down stream PHY system using multiple carriers.

A method and device for self-tuning scales of variables for processing in fixed-point hardware. The device includes a sequence of fixed-point arithmetic circuits configured to receive at least one input signal and output at least one output signal. The circuits are preconfigured with control scales associated with each of the input and output signals. A first circuit in the sequence is configured to receive a first input signal having a dynamic true scale that is different from the control scale associated with the first input signal. Each of the circuits is further configured to determine, for each of the output signals, an adaptive scale from the control scale associated with the output signal based on the true scale of the first input signal and the control scale associated with the first input signal, and generate, from the input signal, the output signal having the associated adaptive scale.

Methods and apparatus for monitoring wideband GHz spectrum for wireless communication, and sensing and decoding respective frequency components of a time-varying signal corresponding to the monitored spectrum. Concepts relating to sparse Fast Fourier Transform (sFFT) techniques facilitate identification of one or more frequency components of a sparsely occupied spectrum by sub-sampling the signal corresponding to the monitored spectrum at a sampling rate below the Nyquist criterion. The disclosed methods and apparatus may be implemented using conventional relatively low-power wireless receivers and using off-the-shelf relatively inexpensive low-speed and low-power analog-to-digital converters (ADCs) typically employed in WiFi devices or cellular phones, in tandem with unique processing techniques based on sFFTs and sub-Nyquist criterion sampling, and have demonstrated efficacy even in scenarios where the monitored spectrum is not sparse.

An apparatus includes a transceiver configured to receive, over a wireless communication channel, at least one controlled-noise signal. The apparatus also includes a processor, operatively coupled to the transceiver. The processor is configured to train, based on the at least one controlled-noise signal, a noise prediction model for the wireless communication channel, and generate, based on the trained noise prediction model, a noise prediction for the wireless communication channel. The processor is also configured to determine, based on the received at least one controlled-noise signal and the noise prediction, a score function for the wireless communication channel.

A system and a method are disclosed for decoding in wireless communications. In some embodiments, a method includes receiving a reference signal; generating a channel estimate, based on the reference signal; determining a channel estimation error metric for the channel estimate; receiving a transmission; calculating a log likelihood ratio, based on the channel estimation error metric, for each of a plurality of bit positions of the transmission; and decoding the transmission based on the log likelihood ratio. The calculating of the log likelihood ratio may include calculating a corrected log likelihood ratio based at least on an uncorrected log likelihood ratio.