Using LTE in 4G satellite communications: Increasing time diversity through forced retransmission

In this paper, we investigate the applicability of the 3GPP Long Term Evolution standard to mobile satellite systems. In order to counteract the satellite specific propagation conditions, we propose a novel inter-TTI (transmission time interval) interleaving technique allowing to break the channel correlation in slowly time varying channels. The Inter-TTI transmission is achieved through the reuse of the existing HARQ facilities provided by the LTE physical layer. Simulation results show that the proposed technique can be successfully used to improve the performance of the LTE physical layer when applied to the transmission over satellite links. Performance improvement depends on the considered parameters, while complexity can be traded off with the data rate to achieve the best quality of service for the considered system.