The principle of channel overloading and design of some practical schemes
Florence Nadal, Hikmet Sari · European Transactions on Telecommunications · 2007
Abstract Channel overloading, which refers to accommodating a larger number of users on a channel than can be achieved with orthogonal signalling, is currently a very hot topic for future wireless systems. A number of approaches have been described in the literature and the most efficient of them are based on using multiple sets of orthogonal signal waveforms. Multiuser interference, which is inherent to channel overloading, is handled using maximum likelihood (ML) detection or iterative interference cancellation. In this paper, we discuss the principle of channel overloading and give the overload limits with different signal constellations. We interpret the various channel overloading schemes available in the literature as multilevel coding of an expanded signal constellation, and this interpretation gives us insight into their performance and limitations and enables us to construct some novel multiple access schemes. Copyright © 2007 John Wiley & Sons, Ltd.