摘要
Orthogonal time frequency space(OTFS)modulation is a recently proposed modulation scheme that exhibits robust performance in high-Doppler environments.It is a two-dimensional modulation scheme where information symbols are multiplexed in the de⁃lay-Doppler(DD)domain.Also,the channel is viewed in the DD domain where the chan⁃nel response is sparse and time-invariant for a long time.This simplifies channel estima⁃tion in the DD domain.This paper presents an overview of the state-of-the-art approaches in OTFS signal detection and DD channel estimation.We classify the signal detection ap⁃proaches into three categories,namely,low-complexity linear detection,approximate max⁃imum a posteriori(MAP)detection,and deep neural network(DNN)based detection.Simi⁃larly,we classify the DD channel estimation approaches into three categories,namely,separate pilot approach,embedded pilot approach,and superimposed pilot approach.We compile and present an overview of some of the key algorithms under these categories and illustrate their performance and complexity attributes.
