Research On The Cross-Layer Adaptive Techniques Of AeroMACS

Aeronautical Mobile Airport Communication System(AeroMACS)is a broadband wireless communication technology based on the Worldwide Interoperability for Microwave Access(WiMAX)standard.It could provide secure and reliable services for aircraft access,and meet the needs of the civil aviation traffic management,as well as airport operations.WiMAX could well adapt to complex environment,becoming one of the most promising wireless interface technologies with most research values.However,how to resist the time-varying and fading characteristics of the wireless environment,and make full use of spectrum resources to provide high-speed communication services,is one of the research priorities and difficulties in mobile WIMAX technology.This thesis is based on cross-layer thoery,with the the primary goal of promoting system throughput.Developed from the basic thoery to the innovative exploration,the key technologies in the AeroMACS receiving system are studied,including adaptive modulation coding(AMC),hybrid automatic repeat request(HARQ),adaptive multiple input multiple output switching(AMS),and channel prediction algorithms in mobile scenarios.The main work and achievements of the thesis are as follows:Firstly,studying WiMAX protocol and its key receiving technology,a simulation platform of WiMAX receiving system is built based on Matlab.To improve the existing basic layered structure,a cross-layer optimization structure based on AMC and adaptive HARQ is proposed.The system could adaptively select the modulation and coding mode and the maximum number of retransmissions according to the channel conditions,thereby achieving spectral efficiency optimization over the entire SNR interval.Secondly,based on the proposed WiMAX cross-layer architecture,MIMO system is studied,including its channel model and capacity.The impact of space-time diversity and complex technology on system robustness and throughput is analyzed,and an adaptive MIMO switching scheme based on maximal throughput is proposed,compromising diversity and complex gain,and promoting full-SNR-range.throughput.At last,based on the cross-layer MIMO scheme,the mobile channel model is studied,and the influence of time-varying channel on the adaptive system performance is analyzed.Then an improved channel prediction scheme based on least squares support vector machine(LS-SVM)is proposed.Compared with the traditional channel prediction algorithm,the proposed scheme promotes the system throughput performance under different speed scenarios,verifying its effectiveness and superiority.