Research On The Space Multiuser Communication Baesd On Direct Sequence Ultra Wideband Systems

Human beings has never stopped curiosity and exploration of the outer space sincetheir birth. And in recent years, with the development of science and technology, peopleare exploration of deep space more and more. Spacecraft from a single, large-scale tocomplex, miniaturization development, concept formation spacecraft began to appear,and more and more attention by researchers. DS-UWB (Direct SequenceUltra-Wideband) due to its high data transmission rate, multipath resistance, easy torealize the advantages of the spectrum coexist, and it is suitable for the formation ofbuilding space vehicle communication link. This paper focuses on the space vehiclefleet DS-UWB communication system about several key technologies: multi-userdetection technology, ultra-wideband pulse waveform design and spectrum coexistence.Firstly, this paper analyzes the communication model of DS-UWB systems, thenthe production, transmission and receiving problems of the UWB signal are studied indetail. Analysis of the spatial channel model aircraft in formation over thecommunication system equations are derived and analyzed its link performance. Got thetransmit power, the spread of the relationship between distance and channel capacityand simulation have proved the DS-UWB signal can be used in ultra-widebandcommunication system formation flying and to achieve long distance transmission.After analyzing the performance of DS-UWB receiver system, the error rate is derivedtheoretical formula of multi-user situations, learned traditional coherent receiver is nomultiple access interference suppression and anti-near-far effect capabilities.Secondly, the conventional coherent receiver in a multi-access interferencesuppression and anti-near-far less than the ability to row, this paper proposes twomulti-user detection algorithm. One is to do the equivalent of multi-user detectionproblem of combinatorial optimization problems after using artificial bee colonyalgorithm to solve ideological; Second Lagrange multiplication and division structurecharacteristic function, and then use coherent reception threshold testing and inspectionto correct the likelihood machine output error. The simulation results also verified thatthese two algorithms have good results in terms of error rate, anti-proximity effect andcomputational complexity, in line with the space fleet aircraft DS-UWB communicationsystems.Finally, in view of the UWB system and narrowband spectrum coexistence problem,this paper set up the narrow band system and mutual interference model between UWBsystem, and analyzes each receiving performance, under the influence of respectiveresearch meet certain communication performance under the power of each signal; Andthen through the design have sunk potter ultra-wideband pulse, make two kinds of system of communication signal in the frequency domain separated from each other, sothat the UWB system and narrowband spectrum coexistence.