Emulational Research On Adaptive Frequency Hopping Anti-jamming Communications System Based On Spectrum Sensing

With the development of communication countermeasure technology, electromagnetic environment is deteriorating, electromagnetic environment is interfered and sabotaged by the enemy at any time. Therefore, the electromagnetic environment reconnaissance technology and communications systems technology has become the key of communication countermeasure technology. To give a depth study of adaptive frequency hopping anti-jamming technology, this thesis is point at Spectrum sensing, FH Communication and Adaptive anti-jamming technology.Research on spectrum sensing algorithm of interfering signals. Thinking about the impact of uncertain factors of noise, we propose the RE-ED(Range of Eigenvalue-Energy Detection) sensing algorithm. The RE-ED sensing algorithm is based on Random Matrix Theory(RMT). By means of the multiple directional antennas receiving system, RE-ED sensing algorithm has an analytical of the range of eigenvalue and average energy. This algorithm reduces the effect of noise uncertainty. Considering that the noise factor is not included in the decision threshold, the detection process is not required any priori knowledge of the signal and noise. The algorithm is analyzed and simulated to prove that compared with common protocol, this method has strong robustness in the influence of noise uncertainty, and when the signal-to-noise ratio performs fine, the detection probability is converged to 1. Furthermore, when the signal-to-noise ratio is deteriorating and the noise is uncertain, the algorithm combining ED algorithm with RE-ED algorithm ensures that the whole detection probability is greater than 0.6.Establish the hopping communication model. Directing against the adaptive interference frequency hopping communication systems, it’s of necessity to establish a hopping communication system to meet the target. Thinking about the hopping system, it’s important to have knowledge of the hopping system, including the theory, the mathematical model and the main characteristics. Aiming at the target, the main parameters are discussed in this thesis. The hopping communication model is simulated to prove that it has satisfied the four targets designed by the system.Simulation of the adaptive interference frequency hopping communication systems. In the reality environment, the undesired signals are unavoidable. According to the features of different jams, the jams are divided into three types: blocking interference, broadband and full-band interference, jamming tracking of interference. Pointing at the three types, three adaptive interference frequency hopping communication systems are proposed, including: adaptive interference gap communication system, adaptive power frequency hopping anti-jamming communication system and adaptive jump-speed frequency hopping anti-jamming communication systems. The theoretical research, parameter analysis, modeling and simulation are carried out in accordance with three systems.The results show that the spectrum of the three frequency hopping communication systems and the interference spectrum avoid overlapping, achieving the goal of anti-interference. At the same time, the probability of error converges to 0.05, and the rate of convergence is greater than 85%. Consequently, the adaptive interference systems have obvious anti-interference effects.