This paper first introduces per-path pulse distortion in multiuser detection for ultra-wideband communications. A new generalized RAKE structure that estimates and compensates for the pulse distortion is used. An finite-impulse response filter representation of the per-path impulse response is used and estimated. The new structure greatly improves the system performance. With four users considered in our simulations in a high-rise building environment, it is found that the average performance of the generalized RAKE using minimum mean-square error (MMSE) detection is improved over the conventional RAKE by 1.8 dB. Both synchronous and asynchronous transmission schemes for decorrelating detector and MMSE detector are considered.