Low complexity OTFS channel equalization algorithm based on CLU-MMSE

Abstract: In view of the high computational complexity of traditional linear equalization algorithms in Orthogonal Time Frequency Space (OTFS) systems, a minimum mean squared error (MMSE) channel equalization algorithm based on Matrix Chunking Lower and Upper Triangle-Decomposition (CLU) is proposed. The proposed algorithm derives the structural properties of the chunked MMSE equalization matrix by using the block diagonal structure of the Cyclic Prefix OTFS (CP-OTFS) time-domain channel matrix and the quasi-band structure of its block matrix. On this basis, triangular decomposition combined with forward and backward substitution algorithms is used to avoid matrix inversion, which can greatly reduce the complexity of the MMSE algorithm without sacrificing its performance.

Keywords: OTFS; equalization algorithm; MMSE; Lower and Upper Triangle-Decomposition