Adaptive Interference Suppression Based on Lv Distribution for DSSS Communications

It is generally difficult to effectively eliminate intentional multiple component interference in any communication systems mainly because of the difficulties in accurately estimating the parameters of interference particularly in low signal-to-noise ratio (SNR) environments. This paper proposes effective methods of adaptive interference suppression based on Lv distribution (AISL) for direct sequence spread spectrum (DSSS) communications. Since the recently reported Lv distribution (LVD) provides better concentration of signal energy in the domain of frequency-chirp rate than other reported methods, it achieves performance improvement on estimating the parameters containing multiple linear frequency modulated (LFM) signals. With the desirable properties of the LVD, the proposed interference suppression methods are able to excise interference of multiple components. The proposed methods firstly examine if the received signal is interfered by using a high-order statistics, known as skewness, to measure the distribution concentration of the received signal in the LVD domain. Then the interference excision process is employed only when the interference is present. Two methods, i.e., AISL-I based on the concept of interference cancellation and AISL-II based on phase cancellation and filtering, are investigated. The merits of these methods are analyzed and compared in terms of bit error rates (BERs). Results of Monte Carlo experiments are also presented to show the effectiveness of suppressing interference by the proposed methods.