Error performance of a pulse amplitude and position modulated ultra-wideband system over lognormal fading channels

In this letter, the error performance of an ultra-wide-band (UWB) system with a hybrid pulse amplitude and position modulation (PAPM) scheme over indoor lognormal failing channels is analyzed. In the PAPM UWB system, input data is modulated onto both the pulse amplitudes and pulse positions. The receiver employs a RAKE to combine energy,contained in the resolvable multipath components. Derivation of closed-form error rate expressions of. the system in lognormal fading channels is based on approximating a sum of independent lognormal random variables (RVs) as another lognormal RV using the Wilkinson's method. Given the same delay spread of the channel, the proposed PAPM scheme can provide a higher throughput than the binary pulse amplitude or pulse position modulation scheme.