Kalman Filter Based Precoding Approach for Inter-Beam Interference Cancellation in Maritime MTC Satellite

The Low Earth Orbit (LEO) satellite for the maritime Machine Type Communication (MTC) is usually equipped with a multi-beam antenna and uses full frequency multiplexing which can increase communication capacity. However, it brings serious inter-beam interference. In this regard, precoding technique is considered to eliminate inter-beam interference. However, conventional precoding algorithms represented by direct inversion bring higher complexity. To this end, we combine the system signal model with the Kalman filter equation and propose a precoding scheme without training sequence in the form of Kalman filter. This scheme can obtain an approximated matrix of the channel inverse matrix. Firstly, we define the channel matrix as the measurement parameter and the precoding matrix as the Kalman state. Then, the difference between the received signal and the transmitted signal is defined as the difference of the Kalman equation as a control factor combined with the Kalman gain. Finally, minimizing control factor through a finite number of iterations to generate the optimum precoding matrix. The numerical results show that the Kalman-based precoding algorithm is more suitable for MTC satellite inter-beam interference cancellation which can gain an improvement in Symbol Error Rate (SER) and system sum rate.