23 results about "Maximum likelihood detection" patented technology

The invention belongs to the technical field of wireless communication, and particularly relates to a communication sensing integrated system based on non-orthogonal AFDM (Alternating Frequency Division Multiplexing). According to the system, a bandwidth compression factor is introduced into an AFDM framework to construct a non-orthogonal waveform, and controllable overlapping between chirp subcarriers is realized, so that the spectrum utilization rate is improved, and the robustness of the system under a high-speed dynamic channel is enhanced. And a receiving end realizes reliable information recovery through maximum likelihood detection, and processes echo signals in combination with a two-dimensional parameter estimation algorithm so as to realize high-precision sensing of the target distance and speed. The system has good anti-Doppler capability and perception precision performance, and is suitable for communication perception fusion application in a high-speed mobile scene.

The invention belongs to the field of wireless optical communication, and particularly relates to an optical FBMC (Fiber Baseboard Management Controller) dual-mode index modulation communication system and a signal detection method thereof, comprising the following steps: Step 1: transmitting two constellation modes by using all available subcarriers, and simultaneously retaining diversity gain of index modulation; 2, optimizing a dual-mode constellation through phase rotation and amplitude scaling, and generating an optimal constellation suitable for the optical FBMC system; 3, designing a deep learning assisted signal detection algorithm, and detecting the sent information; and Step 4, optimizing hyper-parameters of a signal detection algorithm by using an artificial mouse algorithm. Simulation and experiment results show that the system improves the bit error rate performance of the system through the constellation design, and realizes the bit error rate performance close to maximum likelihood detection on the premise of greatly reducing the detection complexity.

The invention discloses an OTFS cross-domain iteration detection method and system based on a penalty term sharing alternating direction multiplier method, mainly solving the problem of poor performance in a high-order modulation scene in the prior art, and the scheme comprises the following steps: a sending end sends a time domain signal; a receiving end receives the sent signal and constructs a penalty term sharing maximum likelihood detection problem and an augmented Lagrange function about the received signal; solving a penalty term sharing problem by utilizing an alternating direction multiplier method to obtain time domain posterior information, and calculating out-of-time domain information by utilizing the time domain posterior information; information outside a time domain is converted to a time delay-Doppler domain through cross-domain message transmission, and time delay-Doppler domain prior information is obtained; and time delay-Doppler out-of-domain information is calculated and fed back to the time domain module. And repeating the steps of the receiving end until the covariance of the symbol to be detected is smaller than a certain threshold value or reaches the set maximum iteration times, thereby obtaining a final judgment bit. According to the method, good detection performance can still be kept in a high-order modulation scene, and the method can be used for recovering a transmitting signal from an OTFS system receiving signal.

The invention provides a signal detection method and device based on a multi-input multi-output system and a medium, and relates to the technical field of communication. The method comprises the following steps: acquiring a channel coefficient matrix when a multi-input multi-output system transmits a target signal; detecting a first transmitting signal transmitted by at least part of target column vectors in the channel coefficient matrix by adopting a first signal detection algorithm and outputting a first estimation vector, wherein the first signal detection algorithm comprises a zero-forcing detection algorithm; detecting second transmitting signals transmitted by other column vectors except for a part of target column vectors in the channel coefficient matrix by adopting a second signal detection algorithm, and outputting a second estimation vector, wherein the second signal detection algorithm comprises a maximum likelihood detection algorithm; based on the first estimation vector and the second estimation vector, the detection signal corresponding to the target signal is determined, the advantages of the first signal detection algorithm and the second signal detection algorithm can be fully played, and the search space complexity of the detection method is reduced.

The invention relates to the technical field of wireless communication, and discloses a working method and device for fractional space-frequency index modulation mapping based on golden angle modulation. According to the method, subcarriers and information bits are grouped at a sending end, and each group of sending information is jointly mapped into a space-frequency resource unit index and a golden angle constellation diagram symbol through fractional space-frequency index modulation and two kinds of golden angle modulation with different orders, so that space-frequency resource subblocks are obtained. And at a receiving end, estimating a space-frequency resource unit activation index and a golden angle constellation diagram symbol by adopting a maximum likelihood detection algorithm, and finally recovering to obtain original information through demodulation and mapping. Golden angle modulation is introduced into a space-frequency index modulation system, so that the system complexity is reduced under the condition that the spectrum efficiency is not reduced. Moreover, by adopting two kinds of golden angle modulation with different orders, the decimal bit problem is solved, so that the number of transmitting antennas and the number of subcarriers are not limited by the power of 2 any more.

The application discloses an RIS-CSK index modulation method based on Hash mapping and belongs to the technical field of visible light communication and intelligent reflecting surface. The method realizes data transmission by constructing a communication system composed of an LED transmitting end, a Hash mapping module, an RIS reflecting array and a PD receiving array. The transmitting end divides input data bits into CSK modulation data and RIS index data, wherein the CSK data generates an RGB optical signal through M-order color shift keying modulation, and the index data generates an RIS activation mode through a Hash function mapping to control RIS group reflection. The receiving end uses a maximum likelihood detection algorithm to jointly detect CSK modulation symbols and RIS index information, and uses a maximum minimum Euclidean distance optimization strategy to improve the distinguishability between received signals. The application can realize efficient and stable data transmission in a visible light communication scene where a line-of-sight link is blocked, and reduce the system bit error rate.

Provided are a method and device for determining an interference layer modulation scheme, a program product, a communication device and a storage medium, applied to the technical field of communications, the method for determining an interference layer modulation scheme comprising: acquiring first frequency domain received signals on a plurality of first subcarriers, the first frequency domain receiving signal is obtained by converting a time domain receiving signal which is received by the receiver and corresponds to the target user; calculating a first metric value corresponding to each first frequency domain receiving signal; traversing a preset interference layer modulation scheme set for a first subcarrier where the first frequency domain receiving signal whose first metric value is not less than a preset threshold value is located, and calculating a second metric value corresponding to each interference layer modulation scheme based on a maximum likelihood detection criterion; and determining the interference layer modulation scheme with the minimum second metric value as a target modulation scheme corresponding to the interference signal.

A two-step detection method, system and device based on maximum likelihood criterion belong to wireless communication technology field, the method includes detecting and sorting all possible symbol constellation combinations through maximum likelihood detection algorithm, and selecting the symbol constellation combination with the minimum distance value as the preliminary decoding result based on the maximum likelihood criterion to complete the first step detection; setting a detection threshold, and finding all other distance values within the detection threshold range from the distance value corresponding to the preliminary decoding result based on the distance value sorting obtained in the first step detection, and storing the corresponding symbol constellation combination in the alternative set; using a different measurement standard from the first step maximum likelihood detection algorithm, and performing the second step detection on the symbol constellation combinations in the alternative set based on the maximum likelihood criterion to find the symbol constellation combination with the minimum measurement value as the target decoding signal. The application aims to solve the "error code platform" problem and effectively improve the accuracy and reliability of decoding.

The application discloses a kind of intelligent reflecting surface assisted spatial modulation system reflection coefficient optimization method, belong to wireless communication field, the information bits to be sent of sending end is divided into several information blocks with same length, according to each information block selects corresponding active antenna and sends specific signal;Optimize the coefficient of reflecting element on intelligent reflecting surface, maximize the Euclidean distance between different receiving signals;Maximum likelihood detection decoding is used at receiving end, and the original information bits are recovered.The application combines intelligent reflecting surface with spatial modulation scheme, reconstructs wireless channel using intelligent reflecting surface, increases the Euclidean distance between different receiving signals, improves the error performance of system, and can obtain better error performance than existing algorithm under the same condition.

The application discloses a method for analyzing bit error rate performance in a space modulation assisted affine frequency division multiplexing system; in the space modulation mode, information bits are mapped into constellation symbols and indexes of activated antennas, the system experiences a time-frequency double selective channel after affine frequency division multiplexing modulation, linear minimum mean square error equalization is performed on the affine Fourier transform domain received signal after affine frequency division multiplexing demodulation at the receiving end, then the equalized signal is grouped, maximum likelihood detection is performed on each carrier symbol to obtain estimated symbols and activated antenna indexes, and the estimated symbols and activated antenna indexes are demapped into bits; theoretical approximate closed expressions of error probabilities of transmitting symbol detection and activated antenna index detection are derived respectively, and the average bit error rate of the system is obtained; through simulation verification, the performance analysis method provided by the application can effectively measure the average bit error rate performance of the system.

The present disclosure provides a non-coherent user positioning method and system based on an unmanned aerial vehicle integrated with an intelligent reflecting surface, relating to the technical field of integrated sensing and communication of intelligent reflecting surfaces, including: constructing a system model; determining known anchor points, turning off the intelligent reflecting surface, and estimating the angle information of the user to the base station; then turning on the intelligent reflecting surface to obtain an interference-free user-intelligent reflecting surface-base station reflection link signal, and estimating the direct component of the channel from the intelligent reflecting surface to the base station; calculating the orthogonal space of the direct component based on the direct component, and obtaining a received signal containing only the scattered component based on the orthogonal space; based on the received signal containing only the scattered component, solving by an exhaustive search non-coherent maximum likelihood detection method with alternating optimization to obtain the angle estimate of the user to the intelligent reflecting surface; based on the angle estimate of the user to the intelligent reflecting surface, and obtaining the positioning information of the target user according to the relationship between the position information and the angle.

The present application relates to the field of communication signal processing, and relates to a MIMO detection method, device and intelligent fusion terminal based on dynamic detection tree generation, wherein the MIMO detection method based on dynamic detection tree generation comprises: acquiring a multi-antenna receiving signal and channel state information; performing upper triangular decomposition on the channel state information to perform equivalent transformation on the receiving signal; converting a maximum likelihood detection solving process of MIMO detection into a dynamic generation process of a detection tree; initializing the detection tree, starting iteration from the first layer of the detection tree, and stopping iteration until an iteration termination condition is met to determine an optimal path of the detection tree and obtain a MIMO detection result. The present application can reduce the number of calculation nodes in a scenario with a large number of transmitting antennas and improve MIMO detection efficiency.

The invention discloses a large dynamic underwater wireless optical signal detection method based on state counting, and belongs to the technical field of underwater wireless optical communication and signal detection. The method comprises the following steps of: firstly, performing M-time up-sampling on a received signal, and setting a judgment threshold to count photon state count in each symbol period; secondly, a truncated sub-Poisson distribution model is provided according to the truncation characteristic of the symbol 1 under the strong light condition, the probability quality function of the truncated sub-Poisson distribution model can accurately describe the state number distribution rule, and Poisson distribution modeling is adopted under the weak light condition; and finally, estimating distribution parameters of symbols' 0 'and' 1 'according to the pilot signal, and performing symbol judgment based on a maximum likelihood detection method. The method has the advantages of being simple in structure and low in calculation complexity, the detection performance and robustness of the system are remarkably improved, and the method is suitable for complex underwater wireless optical communication scenes.

This invention discloses a noncoherent GFSK demodulation method based on the K-best algorithm. It performs demodulation calculations on GFSK modulated signals using a multi-symbol maximum likelihood detection method. If the number of branches in the current demodulation calculation stage is greater than K, the demodulation value of stage k is calculated. Based on the demodulation values ​​of stages k-2, k-1, and k, and the received symbol value of stage k-1, a conjugate relation value is calculated. K is the preset number of branches to retain in each stage, k is the current demodulation calculation stage, and the conjugate relation value is the relationship between the received symbol value and the demodulation value of stage k-1. The similarity value between the received symbol value and the demodulation value of stage k-1 is calculated based on the conjugate relation value and the corresponding branch integrator value. The K branch demodulation values ​​with the highest similarity values ​​are retained. The demodulation values ​​of the next K branches are calculated based on the retained K branch demodulation values ​​until stage T demodulation calculations are completed. The maximum value among the K branch demodulation values ​​of stage T is selected as the final demodulation value, where T is the observation length of the multi-symbol maximum likelihood detection method.

The embodiment of the application discloses a backscattering communication adjacent frequency interference suppression demodulation method and device for cellular passive Internet of Things, and relates to the technical field of wireless communication. The method comprises the following steps: acquiring an OFDM signal, respectively performing signal processing and deconvolution on the OFDM signal to obtain a modulation signal and a sending signal, and training a neural network to obtain a reconstruction model; receiving a time-domain OFDM signal, reconstructing the time-domain OFDM signal through the reconstruction model, and obtaining an adjacent band interference signal generated by time-domain OFDM signal leakage through a band-pass filter; respectively performing Fourier transformation on the time-domain OFDM signal and the adjacent band interference signal, performing maximum ratio combining after interference elimination, and then performing maximum likelihood detection to obtain original information corresponding to the time-domain OFDM signal. The neural network reconstruction model is constructed to effectively process the OFDM signal, high-precision reconstruction of the signal is realized, accurate identification and elimination of adjacent band interference are realized, and the problem that the prior art cannot suppress interference, resulting in high bit error rate of the communication system and low communication quality is solved.

The invention discloses a spatial modulation method and system assisted by double intelligent reflecting surfaces, and particularly relates to the technical field of wireless communication, and the method comprises the steps: dividing a to-be-transmitted information bit into two parts of data blocks; the sending end modulates a constellation symbol according to the first data block, and assigns a receiving antenna index according to the second data block input bit information; the two intelligent reflecting surfaces adjust the phases of all reflecting units in the intelligent reflecting surfaces, so that the signal power on the target receiving antenna corresponding to the two intelligent reflecting surfaces is maximized; and the receiving end detects the receiving antenna index and the sent data symbol in a maximum likelihood detection mode according to the received signal, and recovers the information bit. According to the invention, communication is carried out through the double intelligent reflecting surfaces, so that the error rate of the system is reduced, the signal receiving quality is improved, and the system performance is improved.

The invention discloses a space-time shift keying constellation generation and bit mapping method in a secure communication scene. The method comprises the following steps: S1, a base station acquires statistical channel information of related links of legal users and eavesdropping users; s2, the base station designs a space-time shift keying dispersion matrix set, a power distribution scheme, an amplitude phase shift keying constellation set and a bit mapping scheme according to the channel information; s3, according to the input bit stream, the base station modulates the modulated amplitude phase shift keying symbol to amplitude phase shift keying, the modulated amplitude phase shift keying symbol is sent by the base station, and the space-time shift keying symbol is modulated to the intelligent reflecting surface and is transmitted in a space-time shift keying mode; and S4, after the modulated amplitude phase shift keying symbol and the space-time shift keying symbol are propagated through a wireless channel, a legal user and an eavesdropping user receive joint information, and then the space-time shift keying symbol and the amplitude phase shift keying symbol are jointly detected and demodulated through a maximum likelihood detection mode. According to the invention, the network spectrum utilization rate can be improved and the bit error rate performance of legal users is improved.

The present disclosure discloses systems and methods of calculating a near-maximum likelihood detection (MLD) performance capability signal to interference plus noise ratio (SINR) according to instructions stored in non-transitory computer readable memory that when executed by a processor of a multiple-input, multiple output orthogonal frequency-division multiplexing (MIMO-OFDM) wireless communications receiver device cause the processor to perform operations including the processor acquiring Hi and noise variance σn2 for each subcarrier of a set of subcarriers between a MIMO-OFDM wireless communications transmitter device and the wireless communications receiver device, computing an average received bit mutual information rate (RBIR) over all subcarriers, converting the average RBIR to an effective SINR; and selecting a modulation coding scheme (MCS).

The present invention discloses a method for calculating the bit error rate of an artificial noise-assisted MIMO system under a non-perfect channel. Through the method in which the communicating parties mutually send channel pilot sequences, both the transmitting and receiving ends obtain the main channel estimation information. The transmitting end performs QPSK modulation on the confidential binary information data, and then generates zero-space artificial noise and a precoding matrix according to the main channel state information estimated by the transmitting end, and transmits the artificial noise together with the confidential signal after the precoding processing. The receiving end obtains the main channel state information according to the pilot signal of the transmitting end and generates a deprecoding matrix, decodes the confidential signal, and finally decodes the confidential signal using the maximum likelihood detection method. The artificial noise technology of the present invention increases the difference in noise levels between the receiving end and the illegal eavesdropping end, and improves the confidentiality of communication under a non-perfect channel.

The invention relates to the field of communication signal processing, in particular to an MIMO detection method and device based on dynamic detection tree generation and an intelligent fusion terminal. The MIMO detection method based on dynamic detection tree generation comprises the following steps: acquiring a multi-antenna receiving signal and channel state information; performing upper triangular decomposition on the channel state information, and performing equivalent transformation on a received signal; and converting a maximum likelihood detection solving process of MIMO detection into a dynamic generation process of a detection tree: initializing the detection tree, and starting iteration from a first layer of the detection tree until an iteration termination condition is met so as to determine an optimal path of the detection tree and obtain an MIMO detection result. According to the invention, the number of calculated nodes can be reduced in a scene with a large number of transmitting antennas, and the MIMO detection efficiency is improved.

The invention discloses an MIMO (Multiple Input Multiple Output) detection maximum likelihood estimation method, which comprises the following steps of: acquiring a complex-valued transmitting signal and a complex-valued channel matrix between a receiving antenna and a transmitting antenna to obtain a complex-valued signal at a receiving end of a base station; according to the complex value transmitting signal, the complex value signal of the base station receiving end and the complex value channel matrix between the receiving antenna and the transmitting antenna, an optimal estimation signal is obtained, and MIMO maximum likelihood detection is mapped to an Isin model; mIMO maximum likelihood estimation is carried out through an Isin-MIMO detector, and a user emission signal is restored. The invention also discloses an Isin-MIMO (Multiple Input Multiple Output) detector. According to the method, the technical problem of how to accurately carry out MIMO detection maximum likelihood estimation in real time and output a result is solved.

The present application provides a signal detection method, device and medium based on a multiple-input multiple-output system, which relates to the field of communication technology. The method includes: obtaining a channel coefficient matrix when the multiple-input multiple-output system transmits a target signal; using a first signal detection algorithm to detect a first transmission signal transmitted by at least part of the target column vectors in the channel coefficient matrix and output a first estimation vector, the first signal detection algorithm includes: a zero-forcing detection algorithm; using a second signal detection algorithm to detect a second transmission signal transmitted by other column vectors in the channel coefficient matrix except for part of the target column vectors and output a second estimation vector, the second signal detection algorithm includes: a maximum likelihood detection algorithm; based on the first estimation vector and the second estimation vector, determining the detection signal corresponding to the target signal, so as to fully utilize the advantages of the first signal detection algorithm and the second signal detection algorithm and reduce the search space complexity of the detection method.