Research And System Simulation About Relay Technology Based On Emergency Communication System

With the rapid development of mobile Internet technology, multimedia services which can be applied to mobile terminals are increasing, which makes a higher challenge to a mobile communication system for transmission speed, range and reliability. The relay transmission technology, compared with the single hop communication, can effectively improve the wireless network coverage, communication flexibility and reliability of wireless communication. The research topics are based on our aerial relay project, and this paper proposes a complete solution under air emergency communications relay scheme constitution. Extending from the engineering model, this paper applies other theoretical models such as two-way relay network (TWRN) in the multiple-input-single-output (MISO) models, multiple-input-multiple-output (MIMO) This paper also proceed research in-depth for the relating relay technology used in the proposed models. The main innovations of this paper are as follows:The second chapter presents a complete set of air two-hop relay transmission solutions, including transmission model design, relay mode selection, modulation mode selection, coding selection and design, the frame structure design, data transmission process design. Our single frequency relay transmission model proposed a scheme that the communication between the ground terminal and the air base station are with the Orthogonal Frequency Division Multiplexing (OFDM) method and the communication between two air base stations, and between air base station and the ground terminal are with the Single Carrier (SC) method. Based on this transmission model we build a complete simulation platform, which makes verification to the design and analysis with simulation results.For two-way relay network (TWRN), Chapter III of this paper uses a MISO relay model with analog network coding (ANC) and LDPC channel coding. Under this model, the paper selects Amplify-and-Forward (AF) relay mode and Nakagami-m channel fading model, and also adds two kinds of decoding algorithm of structured Low Density Parity Check Code (LDPC) channel coding. Based on the link simulation platform, this chapter compares the performance that without channel coding and channel coding with two different LDPC decoding algorithm, as well as the performance that with different antennas, and the performance that with different m values of Nakagami-m fading channels. And we obtained the conclusion that Sum Symbol Error Rate (SSER) of the system gradually decrease with the values of m and the number of antennas increasing.For MIMO systems and MIMO detection technology, this paper uses a MIMO relay model in One-way Relay Network (OWRN). Based on this model, this paper analyzes and compares advantages and disadvantages of current main MIMO detection algorisms. Then based on Sphere Detection (SD) and Ordered Successive Interference Cancellation (OSIC) detection, this paper proposed novel detection algorisms that seek a balance between performance and complexity. This novel algorism has the fixed complexity. This paper also added structured LDPC coding technique into this MIMO relay system, and compares performance of the two detection methods with different number of antennas.