A dynamic pairing diversity with interference exploitation for high throughput 4G systems

This paper proposes and analyzes a new cooperative diversity technique that combines users pairing and interference exploitation for enhancing the uplink transmission performance in uplink OFDMA systems suitable for 4G technology. The underlying principle is to pair users on the basis of best interuser channel by utilizing low transmit power communication in the unlicensed band to exchange data symbols. Then, each pair remap their combined symbols according to a predefined rule such that they transmit the same constellation using single dimensional OFDMA to ensure that the signals of each pair combine constructively at the destination. As well as achieving a diversity order of two, the proposed technique attains further performance enhancements by exploiting co-channel interference. The impact of the proposed technique on various modulation orders is considered in this paper. The performance is assessed through Monte Carlo simulation and accurate mathematical analysis. It will be shown that the results from both models closely match and demonstrate that significant BER reduction as well as throughput enhancement are obtained relative to other uplink OFDMA transmission techniques.