Reserch On HF Minimum Essential Communication Technique

Due to the flexibility and the ability of long distance transmission,HFcommunication plays an important role in wireless communication espacially in themilitary communication.In the information-based warfare,the traditional HFcommunication equipments counld not work well with the influence of the bad channelcondition,the narrow frequency band and the technical system,what’s more， faced withthe soft killing or strong electromagnetic interference and other adverse electromagneticenvironment, it almost couldn’t work at all. Based on the current HF radio,this paperstudied the key technology and the implementation scheme for minimum essentialcommunication.This research is focused on the Turbo Equalization, combining the time domainspread spectrum with the frequence domain spread spectrum and the bit interleavingwith the chip interleaving.All these techniques were integrated to be a minimumessential anti-jamming communication method. As for the retrofit design, a HFminimum essential communication card (or system)was constructed.The main work arelisted as follows:1. The technology of low transmission rate with spread-spectrum in band wasdetermined by the characteristic of narrow frequency band. on the basis of thetime-frequency two-dimensional spread spectrum technology, an8sub-bands spreadspectrum scheme was proposed in the audio frequency narrowband channel with300Hzbandwidth, and also the spectrum parameters were analyzed.In a point-to-pointcommunication conditions, using the orthogonal code mapping, the data transmissionrate was highly improved.2. The bit interleaving was analyzed in HF communication. Considered of the lowdata rate and bad channel condition, the anti-jamming capability of interweaves wasanalysed.Based on the chip interleaving principle, the technology combined the bitinterleaving,the chip interleaving with the spread spectrum was applied to make aminimum essential communication method for the HF communication system.According to U.S. military standard, a method using repetitive coding was putforward,which can improve the signal-to-noise ratio of received signal,all this makepreparation for the next turbo equilibrium.3. A turbo system model and a simulation environment were established.Theeffects of turbo equilibrium error rate parameters was simulated and analysed based on the Log-MAP algorithm. this paper give the quantitative analysis of the parameter’seffection to the system performance as well as the computation, the design basis of theturbo equilibrium parameter for HF minimum communication system were present.4. As for the theoretical research, the HF minimum communication system modelwas established and the system function modules were analysed.The systeminformation structure and physical structure were presented.Time-frequency spectrum,interweave,Turbo equilibrium anti-jamming module were integrated.The systemparamerters are analyzed and determined, and the implementation process were givenat last.This research is much significance to promoting efficiency of the HF radio inservice.