Low-complexity GFDM transmission scheme for low earth orbit satellite communications

Abstract

As a promising multi-carrier modulation scheme, Generalized Frequency Division Multiplexing (GFDM) has certain advantages in low earth orbit satellite communications. However, the cost of GFDM to obtain these advantages is the self-interference caused by non-orthogonality and the increase of computational complexity. This paper proposes two low-complexity transceiver schemes for GFDM based on matrix sparsity. Firstly, the paper summarizes two GFDM modulation structures, referred to as structure types I and II, based on modulation data. Next, the modulation matrix in both structures is divided into sub-matrices, and the modulation sub-matrix is made sparse by leveraging the properties of the Fourier transform, so as to reduce the complexity of the transmitter. Similarly, by performing sparse processing on the received matrix and converting it into a block diagonal matrix form, the complexity of the receiver can be effectively reduced. The computational costs of our proposed schemes are analyzed in detail and compared with the existing solutions that are known to have the lowest complexity. The simulation results demonstrate that the two proposed schemes can provide satisfactory low-complexity performance depending on the time–frequency structure.