Type-II hybrid ARQ scheme for DS spread spectrum systems in the presence of narrowband interference

This paper is concerned with a direct sequence spread spectrum (DSSS) system making use of automatic repeat request (ARQ) schemes and operating in the presence of narrowband (NB) interference and additive white Gaussian noise. In this study, we evaluate the system´s throughput efficiency when a suppression filter is employed at the receiver to mitigate the effect of NB interference. Specifically, we investigate how the performance is influenced by various parameters such as the number of filter taps, processing gain, type of interference, and the signal power-to-interference power ratio. The simulation results show that using the suppression filter significantly improves the throughput performance of the hybrid ARQ schemes in the presence of NB interference