Performance and capacity of ultra-wideband transmission with pulse position amplitude modulation over multipath fading channels

Recently, pulse position amplitude modulation (PPAM) has been proposed for ultra-wideband (UWB) communication systems. PPAM combines pulse position modulation (PPM) and pulse amplitude modulation (PAM) to provide better performance and higher system capacity with low computational complexity. A RAKE receiver can make use of the rich multipath of UWB systems to improve system performance and capacity. In this paper we present the performance and capacity of a time hopping (TH) UWB system with PPAM modulation and RAKE reception over a practical multipath fading channel. Error probability and a union bound on performance, single user capacity and a capacity/distance bound based on FCC Part 15 rules, are derived. This analysis is extended to the multiple access case. Numerical results are given to illustrate the analysis