Ultra-wideband High Speed Correlated Frequency Hopping Technology Based On The Compressive Sampling Theory

With the rapid development of the times and technologies, fast hopping and high data rate of frequency hopping system is becoming an important development direction of future communication. Correlated frequency hopping (CFH) technology gets researchers'attention because of it has greater potential than general frequency hopping communication in the respects of data transmission rate and anti-jamming capability, and hardware complexity. Now, CFH technology has been applied in high frequency (HF) communication successfully. By this approach, the weakness of HF communication can be eliminated better, such as serious interference, multipath fading and so on. However, the spectrum resource in HF band is limited and sensitive to environment, which will restrict the hopping rate, width and data rate. Compared with the HF communication system, high band can contain wider hopping bandwidth and greater number of hopping frequencies, so the data transmission rate can be greatly improved, and the signal is harder to be counter-measured by the enemy. Therefore, it becomes a potential way to expand the application of CFH. However, there are still many difficulties to apply CFH in ultra-wideband communication. Faced with bandwidth of hundreds megahertz, ADC has difficulty meeting the requirements of direct conversion reception. Even though it can direct sample the original signals, DSP is also unqualified for the hopping detection for high-speed data stream. In this way, the particular technical methods for applying CFH in wide-band communications must be found.In recent years, compressive sampling (CS) theory has become an active research field in the signal processing. CS states that if the signal is compressible or sparse, the signal can be sampled and compressed at the same time, and the sampling rate can be far below the Nyquist frequency. What's more, the data collection and storage space can be greatly reduced. The paper, which aims at the sparsity of ultra-wideband CFH signal in frequency domain and all kinds of interference problems in the process of radio frequency information acquisition by analog information converter (AIC), studies the high band CFH approach based on CS, and then give out a selective measurement matrix method with interference suppression. When the measurement matrix meets some conditions, CS will be able to eliminate the interference which frequencies are out of the CFH frequency table. Because the relationship of neighbor hop imply the transmitted data, the receiver can realize the information demodulation by hopping detection. However, in order to obtain the sparse frequency parameters, the AIC information needs to be sparse decomposed, and the general sparse decomposition algorithms are difficult to meet real-time requirements on the computational complexity. For this purpose, a sparse hopping signal detection method based on subspace has been developed. When the sparsity K= 4, the algorithm runs faster 5 times than OMP method.The paper includes four parts:first, the basic principle of CFH and key technologies are introduced; second, after expounding the CS theory, the AIC technology for continues analogy signal is raised, and analyzes several signal reconstruction algorithms which take the advantage of CS; third, some fixed-frequency suppression methods based on AIC are analyzed, and presents a selective measurement matrix method with interference suppression; finally, by studying the hopping detection based on interference suppression, a CFH signal detection method based on subspace is proposed.