Performance evaluation of an OFDM-based LMDS using measured channel models

In this paper, the use of orthogonal frequency division multiplexing (OFDM) for LMDS is proposed and investigated. The studies here utilise statistical channel models derived from our earlier field measurements in Singapore and present a more realistic assessment of the proposed system performance. The simulation model considers RS/CC coding, convolutional interleaving and multilevel QPSK/QAM signaling. Robust performance is demonstrated under realistic SNRs for a wide range of system conditions. Recommendations for the choice of a suitable set of OFDM parameters like FFT length and cyclic prefix are presented. The performance of the proposed scheme is also compared with that of an LMS equaliser-based system and shown to be superior under similar channel conditions