Performance of QAM Schemes with Dual-Hop DF Relaying Systems over Mixed η\eta-μ\mu and κ\kappa-μ\mu Fading Channels

Performance of quadrature amplitude modulation (QAM) schemes is analyzed with dual-hop decode-and-forward (DF) relaying systems over mixed $\eta$-$\mu$ and $\kappa$-$\mu$ fading channels. Closed-form expressions are obtained for the average symbol error rate (ASER) for general order rectangular QAM and cross QAM schemes using moment generating function based approach. Derived expressions are in the form of Lauricella's $(F_D^{(n)}(\cdot), \Phi_1^{(n)}(\cdot))$ hypergeometric functions which can be numerically evaluated using either integral or series representation. The obtained ASER expressions include other mixed fading channel cases addressed in the literature as special cases such as mixed Hoyt, and Rice fading, mixed Nakagami-$m$, and Rice fading. We further obtain a simple expression for the asymptotic ASER, which is useful to determine a factor governing the system performance at high SNRs, i.e., the diversity order. Additionally, we analyze the optimal power allocation, which provides a practical design rule to optimally distribute the total transmission power between the source and the relay to minimize the ASER. Extensive numerical and computer simulation results are presented that confirm the accuracy of presented mathematical analysis.Comment: 2

A Survey on MIMO Transmission with Discrete Input Signals: Technical Challenges, Advances, and Future Trends

Multiple antennas have been exploited for spatial multiplexing and diversity transmission in a wide range of communication applications. However, most of the advances in the design of high speed wireless multiple-input multiple output (MIMO) systems are based on information-theoretic principles that demonstrate how to efficiently transmit signals conforming to Gaussian distribution. Although the Gaussian signal is capacity-achieving, signals conforming to discrete constellations are transmitted in practical communication systems. As a result, this paper is motivated to provide a comprehensive overview on MIMO transmission design with discrete input signals. We first summarize the existing fundamental results for MIMO systems with discrete input signals. Then, focusing on the basic point-to-point MIMO systems, we examine transmission schemes based on three most important criteria for communication systems: the mutual information driven designs, the mean square error driven designs, and the diversity driven designs. Particularly, a unified framework which designs low complexity transmission schemes applicable to massive MIMO systems in upcoming 5G wireless networks is provided in the first time. Moreover, adaptive transmission designs which switch among these criteria based on the channel conditions to formulate the best transmission strategy are discussed. Then, we provide a survey of the transmission designs with discrete input signals for multiuser MIMO scenarios, including MIMO uplink transmission, MIMO downlink transmission, MIMO interference channel, and MIMO wiretap channel. Additionally, we discuss the transmission designs with discrete input signals for other systems using MIMO technology. Finally, technical challenges which remain unresolved at the time of writing are summarized and the future trends of transmission designs with discrete input signals are addressed.Comment: 110 pages, 512 references, submit to Proceedings of the IEE