Analysis of the downlink channel estimation methods in communication systems with SCMA

摘要

Sparse Code Multiple Access (SCMA) is a nonorthogonal multiple access method that provides high bandwidth, noise immunity and a larger number of connections compared to traditional methods such as Orthogonal Frequency Division Multiple Access (OFDMA). One of the important problems that negatively affects the quality of communication is multipath propagation. To combat it, various equalization techniques are used, which provide for channel estimation by the receiver. In this paper, we consider three methods for estimating the downlink transmission channel for communication systems with SCMA. The first method is an assessment by reference (pilot) signals, which is classical and is widely used in modern telecommunication systems. The second method under consideration is the assessment of the regenerated information symbols. The third is a blind channel estimate. Algorithms are proposed for all three methods, and mathematical modeling is performed. The results of the dependences of the mean square error and bit error on the signal-to-noise ratio are obtained.