Accurate Error-Rate Performance Analysis of OFDM on Frequency-Selective Nakagami- Fading Channels

Accurate Error-Rate Performance Analysis of OFDM on Frequency-Selective Nakagami- Fading Channels Error rates of orthogonal frequency-division multiplexing (OFDM) signals in multipath slow fading Nakagami- fading channels are considered. The exact density function of a sum of Nakagami- random phase vectors is used to derive a closed-form expression for the error rates of OFDM signals. The precise error-rate analysis is extended to a system using multichannel reception with maximum ratio combining. An asymptotic error-rate analysis is also provided. For a two-tap channel with finite values of Nakagami- fading parameters, our analysis and numerical results show that the asymptotic error-rate performance of an OFDM signal is similar to that of a single-carrier signal transmitted over a Rayleigh fading channel. On the other hand, our analysis further shows that a frequency-selective channel that can be represented by two constant taps has similar asymptotic error-rate performance to that of a one-sided Gaussian fading channel. It is observed that depending on the number of channel taps, the error-rate performance does not necessarily improve with increasing Nakagami- fading parameters.