Adaptive OFDM with feedback aided interleaving and unequal error protection

Abstract

To overcome the frequency-domain fading in orthogonal frequency division multiplexing (OFDM), adaptive OFDM (AOFDM) scheme is proposed. Although conventional AOFDM performs well in single transmit and receive antenna system, the performance advantage of AOFDM system with antenna diversity is not so impressive. In this thesis, we propose an AOFDM scheme based on feedback aided adaptive interleaving and unequal error protection (UEP) in a transmit diversity system using space-time block code. The input information bits are divided into sub-streams and unequally protected by rate compatible punctured convolutional (RCPC) code. The unequally protected bits are adaptively interleaved and transmitted according to the channel quality. In order to implement the proposed scheme, the receiver reports the current channel quality to the transmitter using feedback. We present the semi-analytical bound for BER. Furthermore, we show that the proposed method can improve the bit error probability with the same spectral efficiency and trellis complexity of conventional scheme.