DSSS/BPSK Signal Blind Estimation Research

With the excellent ability of working in lower signal to noise ratio (SNR), strong anti-jamming, lower interception probability, strong confidentiality and mitigating the efforts of multi-path fading, the direct sequence spread spectrum (DSSS) signal has been widely used in modern communication, especially in the military communications. Thus, DSSS signal and its parameter's blind detection and blind estimation under the conditions of low SNR has become an important content of the study of direct sequence spread spectrum communication.This paper introduces the DSSS/BPSK signal's basic model and special features firstly, and then introduces DSSS/BPSK signal's parameter detection methods as followings:1. DSSS/BPSK signal's carrier frequency estimation. Mainly introducing square frequency estimation method:square multiplier method, the relevant multiplier method and correlation spectroscopy method.Then analysis and do the comparison of the estimation performance of various methods through simulation.2. DSSS/BPSK signal's PN sequence rate estimation. Introduces the cyclic spectrum method, and then do the simulation to analysis the performance.3. DSSS/BPSK signal's PN sequence cycle estimation. Mainly introduce the accumulation of auto-correlation method, cepstrum method and the second power spectrum method. Then analysis and do the comparison of the estimation performance of various methods through simulation. 4. DSSS/BPSK signal's PN sequence's starting time estimation. Mainly introduce the measurement method and sliding correlation search method. Then analysis and do the comparison of the estimation performance of these two methods through simulation.Using the introduction above, this paper applied the SOM network in direct sequence spread spectrum (DSSS) signal parameters'estimation and detection. Based on this network, a novel DSSS signal estimation algorithm has been put forward. It is shown from the simulation that our proposed algorithm improves the performance of the PN code sequence estimation and detection compared with the other traditional algorithms, and it is also much simple to implement.Finally, according to the DSSS/BPSK signal detection requirements, this paper gives the system block diagram and introduces the work of the system functions of each module and testing processes.