8 results about "Time domain equalization" patented technology

The application discloses a low-resource-overhead super-high-speed modulation and demodulation method. In view of the signal processing demand faced by high-frequency bands and large bandwidths in millimeter wave and terahertz communication, the application adopts a parallel architecture to meet the high-speed signal processing demand and correct non-ideal characteristics of a channel; and adopts a fusion processing method to fuse interpolation, anti-aliasing, timing interpolation, matched filtering, time domain equalization and decimation into a multi-phase filter, so that the signal overhead caused by high-speed demodulation is greatly reduced. The application can be applied to a millimeter wave / terahertz super-high-speed transmission system, and provides low-complexity super-high-speed modulation and demodulation to meet the performance and resource demand of super-high-speed transmission.

This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for equalization domain selection at a wireless device. A wireless device may be configured to support a selection between time domain equalization and frequency domain equalization for receiving RF signals, which may be performed in accordance with detected channel conditions. For example, if a wireless device detects conditions associated with a relatively dispersive channel, the wireless device may select a frequency domain equalization and, if the wireless device detects conditions associated with a relatively flat channel, the wireless device may select a time domain equalization. In some implementations, performing a time domain equalization may include changing a sampling rate into a symbol rate, such as performing a resampling using a Farrow resampler. Such techniques may include a wireless device selecting an equalization scheme associated with a relatively lowest power consumption for detected channel conditions.

The application provides a time domain adaptive equalization method based on bidirectional superimposed training sequence, which uses superimposed training sequence to improve the spectrum utilization of underwater acoustic communication and the tracking ability of time-varying underwater acoustic channel. The method uses linear superimposed structure at the transmitting end and optimizes the power distribution of training sequence and information symbol, and the receiving end uses forward and reverse adaptive time domain equalization parallel processing to construct a bidirectional iterative optimization framework. Meanwhile, the application designs a time domain symbol-by-symbol training sequence interference cancellation mechanism to eliminate the interference of superimposed training sequence on the underwater acoustic communication system. The application mainly uses superimposed training sequence to improve the spectrum utilization of the system, saves bandwidth compared with the traditional inserted training sequence mode, and uses symbol-by-symbol to eliminate the interference of superimposed training sequence on the system. The simulation results prove that the method can improve the performance of the underwater acoustic communication system.

The invention relates to a reference current compensation method, a storage medium and a device, and the method comprises the steps: determining the reverse compensation amount of a voltage loop of a DC circuit at each moment based on an extracted frequency doubling component, and determining the reference current of the DC circuit based on the reverse compensation amount at each moment and an original current reference value; the method comprises the following steps: determining a current reference instantaneous value of a current inner ring of each bridge arm of a plurality of paths of DC circuits of the energy storage system, and when all bridge arms of the DC circuits work and the current reference instantaneous value of any bridge arm exceeds a preset current upper limit value, executing time domain equalization compensation on the bridge arm. According to the method, a current reference instantaneous value of a current inner loop is compensated to suppress ripples, however, when the compensated current reference instantaneous value of any bridge arm of the DC circuit exceeds a hardware limit value under a heavy load working condition, time domain equalization compensation is performed on the bridge arm, and the ripple suppression effect is improved.

The invention provides a communication decoding method and system suitable for a submarine optical cable, and belongs to the technical field of underwater acoustic communication and optical fiber sensing. The method comprises the steps that a double-pulse heterodyne distributed acoustic sensing system is adopted to sense acoustic vibration signals along a submarine optical cable, and phase modulation optical signals are obtained; performing photoelectric conversion, digitization and band-pass filtering on the optical signal; frame synchronization interception is carried out; recovering a symbol sequence through matched filtering and sampling; a symbol sequence is equalized by adopting an adaptive time domain equalizer based on a recursive least square algorithm, and multipath interference is suppressed; and finally, carrying out QPSK demapping to recover the original bit stream. According to the invention, through combination of high-sensitivity distributed sound sensing and a strong anti-interference time domain equalization technology, the problems of insufficient anti-multipath interference capability and limited signal sensing precision in an underwater complex channel in the prior art are solved, and high-reliability and low-bit-error-rate underwater communication based on the existing submarine optical cable is realized.

Methods, systems, and devices for wireless communications are described. A wireless communications device may receive a waveform including both a first waveform comprising an orthogonal frequency division multiplexing (OFDM) waveform and a second waveform comprising a single-carrier waveform via a set of time-frequency resources. The wireless device may decode the first waveform based on receiving the waveform, where the first waveform includes one or more reference signals. The wireless communications device may decode the second waveform based on receiving the waveform and on a time domain equalization filter that is based on decoding the one or more reference signals, where the second waveform comprises a set of data bits. In some examples, the waveform may further include a third waveform including a second OFDM waveform and the wireless communications device may decode the third waveform including one or more second reference signals based on receiving the waveform.

The invention discloses a time-frequency two-dimensional soft decision feedback equalization method based on vector approximation message passing. The method comprises the following steps: S1, dividing a time domain data block into B sub-blocks containing overlapped symbols; s2, step-by-step equalization is carried out on the bth sub-block, frequency domain equalization is carried out based on soft frequency domain equalization of vector approximation message transmission in each cycle, then time domain equalization is carried out, and b = 1, 2, 3,..., B; s3, the step S2 is executed repeatedly until step-by-step equalization of all the sub-blocks is completed, and one time of Turbo equalization iteration is completed; and S4, repeatedly executing the steps S2-S3 until a preset Turbo iteration number is reached. Through a two-stage structure of frequency domain block-level pre-equalization and time domain symbol-level fine equalization, and in combination with overlapped sub-block processing, robustness and equalization performance under a strong time-varying channel in underwater acoustic communication are effectively improved.

The application relates to a reference current compensation method, a storage medium and a device. The method comprises the following steps: determining a reverse compensation amount of a voltage loop of a DC circuit at each moment based on an extracted double-frequency component; determining a current reference instantaneous value of a current inner loop of each bridge arm of a DC circuit input to a multi-path energy storage system based on the reverse compensation amount at each moment and an original current reference value; and performing time domain equalization compensation on a bridge arm when all bridge arms of the DC circuit are working and the current reference instantaneous value of any bridge arm exceeds a preset current upper limit value. The method compensates the current reference instantaneous value of the current inner loop to suppress ripples. However, when the compensated current reference instantaneous value of any bridge arm of the DC circuit exceeds a hardware limit value under a heavy load working condition, the method performs time domain equalization compensation on the bridge arm, thereby improving the ripple suppression effect.