Analysis of DS-CDMA Transmission Performance in the Presence of Pure Impulsive Interference over Frequency Selective Fading

It is well known that some of urban man-made noises can be characterized by a wideband impulsive noise (pure impulsive noise). The presence of this pure impulsive noise may significantly degrade the wireless digital transmission performance. As the data rate becomes higher and the radio bandwidth becomes wider, the performance degradation due to pure impulsive interference may become larger. In this paper, the DSCDMA transmission performance in the presence of pure impulsive interference is theoretically analyzed. First, the BER expressions are derived for DS-CDMA with antenna diversity and Rake combining in a frequency selective fading channel. Then, the numerical computation based on Monte-Carlo method is performed to evaluate the BER performance. Two types of error floor are observed: one is due to impulsive interference and the other due to the multi access interference (MAI). It is found that the error floor due to impulsive interference becomes larger as the area of impulse and the error floor is linearly proportional to the impulse occurrence rate. Furthermore, it is found that the antenna diversity and Rake combining do not help to reduce the error floor caused by impulsive interference and that the influence of impulsive interference can be negligible when the channel is limited by the MAI (i.e., large number of users are in communication). key words: impulsive interference, DS-CDMA, antenna diver-