Future satellite communication systems should be optimized for mobile services at high frequency bands. In order to keep up with the terrestrial mobile radio communication network and to surmount frequency saturation and scarcity problems, it is an important challenge to consider the property of user mobility and high frequency bands above Ka band in the satellite channel. In this paper, with the movement of terminals into account, we compare and evaluate the performance of satellite communication systems according to the change of the carrier frequency bands and the channel states which are expressed by the location of the receiver and the surrounding environments for traditional land mobile satellite (LMS) channel models, Lutz’s LMS model and Loo’s LMS model, with 2-state Markov chains. The movement of terminals incurs the Doppler effect, which changes the channel condition faster than the weather effect and influences on the carrier frequency shift. Therefore, channel models are analyzed to verify the performance degradation according to the factors that make channel variation in the mobile satellite services (MSS) environment with information theoretical perspective. And then, we compare the difference of performance degradation between traditional communication systems which use low frequency bands and future communication system which use high frequency bands. According to the simulation results, the Lutz’s and Loo’s channel model are investigated for suitability and usefulness in satellite communications at high frequency bands. To propose the solution which solves the problem related to delayed feedback CSI (channel state information), power margins and wastes are investigated and analyzed in the channel depending on the coherence time (velocity of moving user). ⓒ 2017 DGIST
Table Of Contents
Ⅰ. INTRODUCTION 1 -- 1.1 Spectrum saturation problem 1 -- 1.2 Related work 1 -- 1.3 Background scenario 2 -- Ⅱ. ANALYSIS OF SATELLITE CHANNEL MODEL 4 -- 2.1 2-state Markov chain model 4 -- 2.2 Setting for analyzing channel model 5 -- 2.3 Lutz’s LMS channel model 9 -- 2.3.1 Simulation results and discussions for Lutz’s LMS channel model 12 -- 2.4 Loo’s LMS channel model 18 -- 2.4.1 Simulation results and discussions for Loo’s LMS channel model 21 -- 2.5 Comparison between Lutz’s and Loo’s LMS channel model 27 -- Ⅲ. DELAYED FEEDBACK PROBLEM 28 -- Ⅳ. CONCULSION 31