Performance analysis for Impulse Radio and Direct Sequence Impulse Radio in narrowband interference

The impact of narrowband interference (NBI) on two Ultra Wide Band (UWB) systems is analysed. The two systems are Impulse Radio (IR) and a variation of it, termed Direct Sequence IR (DS-IR). The signal to noise ratio (SNR) at the decision device of a correlation receiver is computed for both systems assuming that the NBI is Wide Sense Stationary (WSS) and that the channel is frequency selective. The SNR is expressed by means of a simple equation involving the signal and the interference spectrum. Next a statistical model for the interference is introduced, considering the interference as the sum of a given number of sinusoidal signals with random powers and frequencies. The Bit Error Rate (BER) of IR and of DS-IR is derived. The results are then specialised and compared with simulations in three case studies of practical interest where the NBI is a single jammer with deterministic power and frequency, a multi-tone signal with random frequencies or a grid of interfering signals with random powers.