Outage and average BER analysis of multiband OFDM UWB system with MRC/EGC receiver in log-normal fading channels

Abstract

This paper mainly focuses on the performance analysis of multiband orthogonal frequency division multiplexing (OFDM) based ultra wideband (UWB) system in the presence of log-normal fading channels. For this, an exact probability density function of sum of squared magnitude of log-normal random variables and squared sum of log-normal random variables are used to derive analytical expressions for outage probability and average bit error rate (BER) of multiband OFDM UWB signal at the combiner output. For log-normal fading channel with constant power delay profile, our analysis exactly follows the numerical (Monte Carlo simulation) results. On the other hand, increasing the outage threshold severely effects the outage probability and thus leads to deterioration of system performance. It is observed that among the combining techniques usually used in the receiver, particularly, equal gain combining (EGC) technique gives better BER performance (1.2dB at target BER of 10∼6) compared to maximal ratio combining (MRC).