Research On FH/TH-based Virtual Full-duplex And Its Multi-user Detection Algorithms

High throughput,high real-time and strong anti-jamming capability are required for tactical data networks,in order to achieve command and control,situational awareness,communication,surveillance and other tasks in the complex tactical environment.The Full-duplex technique,which has high real-time performance,improves the utilization of the spectrum and network throughput,through the same band in the same transceiver.Moreover,the frequency hopping and time hopping technique,which is one of the main anti-jamming techniques in tactical data network,has a strong anti-jamming capability.Hence,the virtual full-duplex technique based on frequency hopping and time hopping achieves simultaneous transmission and reception,through the high-speed frequency hopping and time hopping for the network nodes.In other words,any node in the network will not miss receiving information,while sending information.This has a strong appeal to military communications and tactical data links.In the dissertation,a virtual full-duplex technique,based on frequency hopping and time hopping and its multi-user detection algorithm,is studied.The main research contents are as follows:(1)The working principles,for frequency hopping and time hopping and virtual full duplex techniques,are researched,which highlights the good anti-jamming ability of frequency hopping and time hopping systems and the high throughput performance of virtual full-duplex systems.Aiming at the problem that multiple users simultaneously occupy one channel,a multiuser detection method is analyzed,and a multiuser detection scheme suitable for the system is proposed for the virtual full-duplex system based on frequency hopping and time hopping.(2)The throughput performance of the virtual full-duplex system based on time hopping is studied deeply.The signal model and block diagram of virtual full-duplex systems are given,and also the system throughput considering collision constraint is deduced.Since the throughput of the virtual full-duplex system without considering collision constraints is too ideal,the system throughput analyses are presented with collision constraints.The system has good throughput performance,in comparison with ALOHA systems.(3)Aiming at the collision problem of multiple users in the virtual full-duplex system,the multi-user detection algorithm of the virtual full-duplex system is studied,and the information of each user is restored from the overlapping signals of multiple users.The simulation results show that compared with the conventional method,the serial interference cancellation algorithm can improve the error performance of the system,and it is suitable for time hopping virtual full duplex single channel system.(4)A virtual full-duplex system based on time hopping is proposed to extend the single-channel virtual full-duplex system to multi-channel scene.The design method of frequency hopping and time hopping sequence suitable for the system is studied.Three multiuser collision detection and data recovery algorithms,namely collision not processing algorithm,collision zero algorithm and serial collision interference cancellation algorithm,are given for multiuser collision problems that can not be avoided in the system.The simulation results show that the error performance of the serial collision interference cancellation algorithm is the best for the collision avoidance algorithm and the collision zeroing algorithm,and is suitable for the virtual full duplex system of frequency hopping and time hopping.