In this paper, low-complexity channel estimators are proposed for massive multiple-input multiple-output generalized frequency division multiplexing (MIMO-GFDM) systems. In order to combat the effect of non-orthogonality in GFDM, interference-free pilots are used in frequency-domain minimum mean square error (MMSE) channel estimation. Polynomial expansion is used to approximately compute the matrix inverse in conventional MMSE estimation, consequently reducing the cubic computational complexity to square order. The degree of the matrix polynomial can be properly selected to get a required trade-off between complexity and estimation performance. Different weights can be assigned to the terms in the polynomial expansion and be optimized to achieve a minimal mean square error (MSE). Performance limits on the MSE of the proposed estimators are derived. The computational complexity of the proposed MMSE estimators is analyzed and the impacts of the polynomial degree and the pilot subcarrier spacing are also investigated. Numerical results show the accuracy of the proposed channel estimators.
Polynomial Expansion-Based MMSE Channel Estimation for Massive MIMO-GFDM Systems
2020-11-01
933772 byte
Conference paper
Electronic Resource
English