High-throughput, high-performance OFDM via pseudo-orthogonal carrier interferometry type 2

Abstract

OFDM (orthogonal frequency division multiplexing) demonstrates poor probability of error performance in fading channels, and hence many OFDM systems utilize channel coding. The addition of this coding, adding both redundancy and frequency diversity, comes at a cost of reduced overall throughput (typically by a factor of 2). PO-CI/OFDM is as a new methodology to enhance performance in OFDM systems, via channel coding, without bandwidth expansion or decreased throughput. Specifically, by placing 2N symbols pseudo-orthogonally on the N OFDM carriers (via the use of spreading codes) and by introducing rate 1/2 convolutional coding, PO-CI/OFDM achieves the benefit of channel coding in OFDM without the cost of throughput reduction. It is shown that, in BPSK systems, at a bit error rate of 10/sup -3/, this method gains 15 dB over OFDM, equaling the performance of traditional coded OFDM (COFDM) without the throughput reduction.