Estimation of code-width based on Hilbert transform
Qian Ding, Xialin Jiang, Haoqian Huang, Jing-jing Cai, Wei Su · 2017
Automatic estimation of symbol parameters plays a prominent role in electronic reconnaissance and electronic warfare systems. How to estimate the code width without prior knowledge is an important problem in modulation recognition. Hilbert transform can effectively extract the instantaneous mutation characteristics of digital communication signals. In this paper, in order to demodulate MPSK underwater acoustic communication signals without pre-code-width knowledge, a code-width estimation algorithm is proposed by detecting the phase-angle jumps between two adjacent symbols, which is obtained by Hilbert transform. In matlab simulation, the Hilbert transform magnitude of digital communication signals will peak at the time where phase changes occur, and the peak interval is an integer multiple of the symbol period. In this paper, we establish a channel of marine environment, and added different level noises. The theoretical analysis and the actual signal processing show that this algorithm can effectively detect the symbol transition, thus estimating the code width.