Capacity of UWB Impulse Radio With Single-User Reception in Gaussian Noise and Dense Multipath

In this letter, we derive the capacity of ultra-wideband impulse radio (IR) systems employing optimal single-user reception. The environment in which the evaluation is set is that of a dense multipath and equal energy levels for interfering users, where multiple-access interference can be modeled as Gaussian. The investigation covers both binary and$M$-ary pulse position modulation approaches, employing either hard or soft decoding, and is targeted to low-signal-to-noise ratio/low-power environments where IR is supposed to work.