33 results about "Asynchronous interference" patented technology

This invention discloses improved single antenna interference cancellation (SAIC) receivers utilizing joint channel estimation for suppression of interference of co-channel signals. This invention describes the technique to perform joint channel estimation for either synchronous or asynchronous co-channel signals without a prior knowledge of the interfering training sequence or its timing position. The invented joint channel estimation can require initial detection of the desired signal and can be implemented as a multistage equalization structure.

The present invention belongs to the field of underwater acoustic communications, and particularly relates to an asynchronous multi-user access method for underwater acoustic OFDM (Orthogonal Frequency Division Multiplexing). The method comprises the following steps: overlap truncation; interference cancellation; frequency domain oversampling; multi-user channel estimation and decoding; and interference reconstruction. According to the present invention, an asynchronous interference model is established by using an overlap truncation method based on a sliding iteration structure, and then a received signal after interference cancellation is equivalent to a quasi-synchronous MIMO (multiple-input multiple-output) system to realize the multi-user data decoding, so that the asynchronous multi-user access method can be better to take the processing delay and the decoding performance into account, and has practical application value.

Interference management may involve the transmission of interference management messages by wireless nodes that are experiencing interference and appropriate responses by potential interferers that receive the interference management messages. Upon detection of interfering signals, a wireless node may determine whether the signals are from a synchronous interferer or an asynchronous interferer. Based on this determination, the wireless node may use different types of signals to manage the different types of interference. In some aspects, asynchronous interference management may involve backing-off in frequency and / or in time in response to interference signals. Asynchronous interference management may involve transmitting back-off beacons to clear potential interferers from a given carrier. Here, the transmission of beacons by a wireless node may be metered to facilitate fair sharing of communication resources.

The invention provides an interference elimination method and a device under asynchronous interference data, wherein the interference elimination method under the asynchronous interference data comprises the following steps: (1) confirming an interference tipping point j of first time slot data and dividing the first time slot data into first part time slot data and second part time slot data, (2) respectively carrying out interference elimination to the first part time slot data and the second part time slot data, (3) combining the first part time slot data and the second part time slot data which are processed in an interference eliminated mode and obtaining the first time slot data after interference is eliminated. According to the interference elimination method and the device under the asynchronous interference data, the time slot data are divided into two parts, namely an interference part and a non-interference part, and interference elimination to the interference part and the non-interference part is respectively carried out, and thus the interference of the time slot data can be eliminated more effectively.

The invention relates to an anti-interference treatment method based on a navigation management secondary radar test system, which comprises the following steps: S1, initializing original data: initializing the system data of the navigation management secondary radar test system; S2, detecting a dynamic threshold sliding window: extracting an effective pulse signal sequence from the pulse signalsreceived from a navigation management secondary radar function test analyzer; S3, removing asynchronous interference pulse signals: removing the asynchronous interference pulse signals in the effective pulse signal sequence extracted in the step S2 to obtain the effective pulse signal sequence of a target navigation management secondary radar; S4, grouping pulses: grouping the pulses of the effective pulse signal sequence of the target navigation management secondary radar obtained in the step S3 to obtain the integral information data of target navigation management secondary radar; and S5, outputting a result. The invention has the advantage of improving the anti-interference capacity of the navigation management secondary radar test system.

The invention provides a navigation radar dense same-frequency asynchronous interference medium-frequency signal layer suppression method. The method includes: through envelope signals generated through zero medium-frequency signals, finding a position where same-frequency asynchronous interference appears in video azimuth echo; according to recorded same-frequency asynchronous interference position, respectively performing interference suppression in real signals of branches I and Q of zero medium frequency to retain zero medium frequency phase information so as to lay a foundation for coherent processing of subsequent radar signals. In the process of interference suppression, weight coefficient and protection factor are introduced, and the protection factor is utilized to protect original azimuth echo amplitude, so that same-frequency asynchronous interference signals are eliminated while original data are protected to greatest extent from being modified.

The invention provides a channel estimation method suitable for single-antenna interference elimination technology. The method comprises steps of: pre-equalizing a signal so as to obtain a signal sequence estimation value; reducing the sequence estimation value into a burst sequence form and determining direction determination through signal energy; and executing adaptive sequence estimation on a half sequence including a training sequence according to the reference value of the obtained burst sequence and the direction determination. The method comprises three steps of: pre-processing, sequence reduction and direction determination and adaptive channel estimation. The invention also provides a channel estimation device suitable for the single-antenna interference elimination technology of decoupling linear filtering nonlinear balancing method. Thus, asynchronous interference elimination performance is improved.

The present invention relates to a method for common frequency asynchronous interference resistance in the radar signal processing field, especially to a common frequency asynchronous interference resistance method based on the interference spectrum and the MTD filtering amplitude-phase characteristics which can be widely applied in the radar signal processing system. According to the invention, the analysis of spectrum for the asynchronous interference is completed through the MTD filter amplitude-phase characteristics, the time-frequency two-dimensional combination detection is realized through combination of each channel frequency domain information on the basis of each Doppler channel time domain detection in the MTD processing process, and the effective inhibition of the common frequency asynchronous interference is completed while effectively detecting targets so as to basically eliminate the problems of interference or target misjudgement and target false dismissal.

The invention discloses a method for synchronously inhibiting radar clutter and multiple interferences based on power distinction, and is suitable for a signal processing system of sky-wave over-the-horizon radar. The method realizes the separation of strong clutter, interferences and target signal using the power difference among the clutter, interferences and target signal, and can effectively inhibit clutter and multiple interferences including transient interference and shared-frequency asynchronous interference. The specific steps are showed in the figure 1. Compared with the prior method, the method does not need to detect and analyze the clutter and multiple interferences complicatedly, has obvious effect on the randomly varied interferences of all parameters and clutter, and has strong applicability. The invention uses the separated strong clutter as a standard signal to correct phase pollution, can realize phase correction and inhibit the clutter and interferences synchronously, and simplify the signal processing process of the sky-wave over-the-horizon radar. The invention is not limited to the sky-wave over-the-horizon radar system, can be widely applied to multiple large-scale phased array radars, and has wide application value.

The invention provides a processing method of radar co-frequency asynchronous interference video signals. The echo amplitude in each azimuth is endowed with a weight coefficient, namely, different weight coefficients are used to adjust correlations between different pulses and a present pulse, and the problem of a relatively large error of a present sampling point is overcome. The average of every N azimuth echo amplitudes endowed with the weight coefficients is calculated, the calculated average value is endowed with a protection factor, the protection factor is used to protect the echo amplitude in the original azimuth and further to prevent original data from modification to the largest degree while removing the co-frequency asynchronous interference signals, and accurate basis is provided for subsequent data processing of the radar signals. In the processing process, the quantity of pulses can be adjusted properly according to whether adjacent pulses occur in the co-frequency asynchronous interference signals and whether the adjacent pulses include an interfering distance overlap condition, and problems in processing interference signals of different densities can be solved.

The invention provides a layered sequential ratio pipeline leakage monitoring method and system based on optical fiber multisource signals. The method includes the steps that optical fiber central wavelength data transmitted by a standard optical fiber base set and a detection optical fiber base set are collected in real time; environment data and detection data are obtained by demodulating the collected data; the demodulated environment data are analyzed, and environment compensation judgment and inspection are conducted through a sequential ratio method; the compensated detection data are analyzed, and pipeline leakage diagnosis and inspection are conducted by using an improved sequential ratio method based on influence factors constructed through the multisource signals of the detectionbase set; and whether leakage occurs or not is judged and an alarm is given. By creating the two different optical fiber base sets, the environment data are separated from the detection data, and a false alarm caused by environment influences is accurately removed; and a spiral structure is adopted in each base set, so that installing and laying are facilitated, and optical fibers in the base sets are protected against non-synchronous interference. The detection base set improves the operation sensitivity and accuracy of the system through multisource detection, and an early warning functionis provided through stretching and vibrating changing.

The invention discloses a transmitting-interference-resistant wireless communication link adaptive method. The method includes the steps: when a sending node transmits frames to a receiving node by means of A-MPDU (aggregated MAC protocol data unit) frame aggregation, capturing transmission state information of PHY (physical layer) terminals and MPDU subframes in real time, and calculating synchronous interference occurrence probability and asynchronous interference occurrence probability; once loss of the PHY terminals or the MPDU subframes happens, estimating interference factors in communication links according to relation between a each of the synchronous interference occurrence probability and asynchronous interference occurrence probability and a corresponding threshold, immediately executing corresponding measures for transmitting interference resistance to guarantee reliability in frame transmission. By means of estimation of interferences in the links from a sending end, on the one hand, protocol expenditure is saved while frame length is reduced; on the other hand, frame transmissions states are acquired and counted in real time by means of B-ACK frames so as to reason out synchronous interferences and asynchronous interferences in the links to assist the sending end in execution of optimal measures for transmitting interference resistance, proper frame transmission speed is selected, and the problem of inaccuracy in estimation of the synchronous interferences and the asynchronous interferences is avoided.