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The receiver performance is degraded by nonlinear memory problem in communication system. The pre-distorter techniques are an effective technique to compensate for the nonlinear distortion of the HPA without memory effects. However, memory effect of HPA can no longer be ignored when data signal is transmitted in high speed. Many adaptive pre-distorter schemes have been studied to compensate for memory effect problem of HPA in transmitter. The complexity and cost of satellite will increase when using adaptive pre-distorter in satellite communication system. In this paper, we propose receiver feedback closed loop pre-distortion technique in order to compensate for nonlinear problem of HPA with memory problem. The purpose of this paper is to reduce complexity and cost of satellite design by using only pre-distorter at terrestrial station.

In this paper, we propose closed loop satellite communication system to compensate for nonlinear problem of HPA in satellite. Conventional pre-distorter schemes can only compensate for one HPA nonlinear problem. But, the proposed schemes can compensate for nonlinear problem including two HPA model. The purpose of this paper is to increase efficiency of HPA and to secure high communication quality by closed loop pre-distortion technique with feedback information at the receiver. Simulation result shows that the proposed scheme can compensate for nonlinear problem including two different HPA models.

Single carrier M-APSK modulation technique is well used in satellite communication system due to the low PAPR so that the we can expect more resistance to the non-linear distortion. Although TWTA has high amplification efficiency, it may produce serious non-linear distortion. Memory effect that can be observed in the very high speed data rate would be another harmful effect. In this paper, to compensate non-linear distortion efficiently in case of HPA model with the memory effect, we design adaptive pre-distorter using NLMS (normalized least mean square) algorithm. Through the simulation, we confirm that the pre-distorter using NLMS algorithm is able to improve the BER performance than existing pre-distorter.