An apparatus is provided for using a square wave digital chirp signal for optical chirp range detection. A laser source emits an optical signal and a RF waveform generator generates an input digital chirp signal based on the square wave digital chirp signal. A frequency of the optical signal is modulated based on the input digital chirp signal. A splitter divides the optical signal into a transmit optical signal and a reference optical signal. A detector combines the reference optical signal and a return optical signal from an object. The detector generates an electrical output signal based on the combined reference optical signal and the return optical signal. A processor determines a range to the object based on a characteristic of a Fourier transform the electrical output signal. A method is also provided for using the square wave digital chirp signal for optical chirp range detection.

In certain aspects, a device for wireless transmission includes a transmission path, a feedback path, and a DPD control module. The transmission path includes a digital pre-distortion (DPD) conversion module configured to perform pre-distortion processing on an amplitude and a phase of a transmission signal based on a pre-distortion processing strategy. The transmission path further includes a power amplifier coupled to a downstream of the DPD conversion module and configured to amplify a power of the transmission signal. The feedback path is coupled to the transmission path at the downstream of the power amplifier and configured to generate a feedback signal. The feedback path includes a static gain compensation module configured to be activated during an initial time period of each frame to track and update a static gain for the feedback signal and configured to hold the static gain after the initial time period of each frame. The DPD control module is coupled to the feedback path and the DPD conversion module and configured to adjust the pre-distortion processing strategy based on an amplitude difference and a phase difference between the transmission signal and the feedback signal.

A user matching and power distribution methods for a MIMO-NOMA downlink communication system is provided. The user matching method includes: dividing all users into a strong user group and a weak user group according to a channel gain sorting result; and sequentially selecting a user in the strong user group, calculating a correlation coefficient between the user and each user in the weak user group, selecting a weak user with the highest correlation coefficient as a weak user in a cluster where the strong user is located, and excluding matched users from respective user groups, until the matching between all strong users and weak users are completed. The present invention enables weak users in a cluster to experience less inter-cluster interference in scenarios where the channel correlation between users is relatively low, thereby improving the total throughput of the communication system.

Introduced here is at least one technique to better estimate interference at a receiver. The technique includes receiving a plurality of reference signals, which each have information indicative of noise. Thus, the technique further includes, for each reference signal, determining a noise estimation and determining a distance metric and log-likelihood ratio (LLR) of the noise estimation. Once the distance metric and LLR of each reference signal is determined, the receiver can determine a final LLR based on the distance metric and LLR of each reference signal. In this manner, a final LLR is determined. This technique can be applied by any device operating on MIMO technology.

Equalization circuitry for a data channel in an integrated circuit device includes an analog equalization stage coupled to the data channel, and a digital signal processing stage downstream of the analog equalization stage. The digital signal processing stage generates control signals to control the analog equalization stage, and includes a digital equalization stage that operates on output of the analog equalization stage. The analog equalization stage may further include an enhanced processing stage for optical signals, which may be selectably coupled to the analog equalization stage. The analog equalization stage may include at least one feed-forward or feedback equalization stage, and a decision stage that outputs decision signals at one of a first plurality of signal levels. The enhanced processing stage operates on the decision signals to output enhanced decision signals at one of a second plurality of signal levels of higher resolution than the first plurality of signal levels.

As 5G, and especially 6G, push into ever-higher frequencies, phase noise presents an increasing problem. Disclosed are procedures and modulation schemes to mitigate phase noise and permit messaging at higher frequencies. Each modulation scheme provides phase-noise immunity by configuring modulation states with large phase acceptance regions. A message element is faulted if its sum-signal amplitude or phase is in an exclusion zone. Modulation schemes with fewer phase levels, more amplitude levels, and very broad phase acceptance regions are necessary for high frequency operation where phase noise dominates. Using allowed states with the maximum amplitude modulation in both branches can provide nearly 90-degree phase acceptance. Requiring that the two branches be equal provides nearly 180-degree phase acceptance. Further requiring that the amplitude levels be positive can provide total phase-noise immunity, with a 360-degree allowable phase range. Embodiments can thereby enable high frequency communication despite phase noise.

A method for precoding to mitigate nonlinear distortions and a precoder for performing the same are disclosed. The precoder for mitigating distortions of a communication signal may include a filter configured to generate a filtering signal based on a third signal and filter coefficients corresponding to a selected signal generated based on a first signal, a second signal, and the third signal, and a modulo operator configured to generate the third signal by performing a modulo operation on the second signal, wherein the second signal is generated based on the first signal and the filtering signal.

A method of wireless communication includes selecting, by a user equipment (UE), a first codepoint from a codebook based on control information to be transmitted to a base station. The codebook is associated with non-coherent transmissions from the UE to the base station. The method further includes generating, based on the first codepoint and a scrambling sequence that is associated with the UE, a second codepoint representing the control information. The method further includes transmitting the second codepoint by the UE to the base station.

Embodiments of this application disclose a board, an optical module, a MAC chip, a DSP, and an information processing method. The board in the embodiments of this application includes a media access control (MAC) chip, a digital signal processor (DSP), and an equalizer. The MAC chip is configured to send first information to the DSP at an optical network unit (ONU) online stage, where the first information includes a first ONU identifier. The DSP is configured to receive the first information, and determine a first reference equalization parameter, where the first reference equalization parameter is related to the first ONU identifier. The DSP is further configured to set an equalization parameter of the equalizer to the first reference equalization parameter.

A method is disclosed for mitigating phase noise at high frequencies in 5G and 6G. Quadrature modulation schemes, in which orthogonal branches are amplitude modulated, are susceptible to phase noise which rotates the branches, causing demodulation faults. Disclosed is a single-branch reference signal that can mitigate phase noise. The transmitter can transmit a particular resource element having a normal amplitude in one branch, and zero amplitude in the orthogonal branch. The receiver can then measure the amplitudes of the particular resource element as-received (with phase noise), and determine a phase rotation angle according to a ratio of the two branch amplitudes. The receiver can then correct the branch amplitudes of each message element, and thereby negate the effect of the phase noise. The disclosed procedures can thereby make high-frequency, high-reliability communication feasible, at extremely low cost.