Iterative multiuser detection for high spectral efficiency reverse-link of multibeam satellite via expectation propagation

Multibeam satellite communications employing full frequency reuse have the potential to increase spectral efficiency. However, they suffer from severe inter-beam interference. An expectation propagation based message passing algorithm is proposed for decoding multi-user transmissions in the reverse link of multi-beam satellite communications with full frequency reuse. Compared with an iterative MMSE (Minimum Mean Square Error) interference cancellation algorithm, the proposed algorithm reduces the cubic complexity to square complexity in the number of interfering beams. Numerical results show that the proposed algorithm outperforms the iterative MMSE algorithm slightly in terms of bit error rate when the energy per bit to noise power spectral density ratio is low. The performance of both algorithms is the same for other cases.