This paper studies the in-band interference of timehopping spread spectrum (TH-SS) UWB signals to narrow band receivers. Based on the analysis of general power spectral density (PSD) of TH-SS UWB signal, the interference of UWB signal can be partitioned into two parts: (1) additive white Gaussian noise interference (2) jamming tone interference. Following this framework, a novel analytical symbol error rate (SER) evaluation method of BPSK signal due to UWB interferences is proposed. It has been found out that as the number of inband jamming tones increases, the UWB interference effect tends to be closer to the effect of equivalent Gaussian noise.

In this paper, we develop expressions for the transfer delay of an M-stage hybrid automatic repeat-request (HARQ) protocol. These generally applicable expressions make no assumptions about the quality of the feedback channel and explicitly account for both feedback errors and their associated delays. Both infinitely repeating and terminated HARQ protocols are considered. Through a series of examples, we demonstrate that these expressions admit earlier results as special cases or applications, while providing additional insight on the contributions of various error and delay terms.