3 results about "Maximum likelihood detection" patented technology

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.

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.