Listener From The Network Carrier Methods Based On Correlation Detection Dfh

Wireless self-organizing frequency hopping network is a wireless transmission based on frequency-hopping (FH) at physical layer and wireless self-organization approach to networking in a military communications network. The network using FH to improve anti-jamming capability and self-organizing network technology to increase the network's flexibility and survivability, is an ideal tactical wireless network.Frequency hopping communication technologies and wireless self-organizing networks both have very in-depth research home and abroad, have many results. But the research of wireless self-organizing frequency hopping network technology, the organic combination of two technologies, is in the initial stage. Currently there are a lot of technical problems in FH Ad hoc networks. The paper focuses on differential frequency hopping(DFH) frequency-hopping self-organizing network technology.The paper first introduces the frequency-hopping communication technologies and wireless self-organizing networks at home and abroad Research, summarizes the their respective characteristics and key technologies of the FH communication and Ad hoc ,through the analysis of existing self-organizing network under the FFH system ,the synchronization of FH system is difficult to achieve, thus affecting the FH network links to build. The DFH that asynchronous FH technology, which receive full band in the work, does not need FH synchronization. with the jump in the DFH system increasing, the affect of network link is smaller.Subsequent analyzes the principles, characteristics and network technology of the DFH technology. Using the symbol detection receiver model, analyzes the probability between two received frequency points, establish the relationship between related probability,SNR and number of carrier. This paper presents a method that by statistical correlation between adjacent frequency points in received sequence, then calculate the probability of the frequency sequence. According to the different related probability of different channel conditions, this method can judge whether the carrier is detected. Simulation results show that the method is feasible, and under the conditions of SNR in the range of 10 to 20dB, detection length 100 to 200 jumps, determine the relevant probability threshold of 25%, the test results of false-alarmprobability and false dismissal probability tend to 0, ensure the accuracy of the method and effective.Finally, sum up the work of this article, and point out after the Carrier Sense working, further data link layer protocol used to improve the network service performance will be necessary.