On the Sum Rate of MISO Rate Splitting with Spatial Randomness

Efficient and intelligently designed multiple access schemes constitute a promising technology for achieving massive connectivity, required by the forthcoming fifth generation and beyond networks. In this work, we investigate the performance of the sophisticated rate splitting (RS) scheme for a multiple-input single-output broadcast channel with two receivers. We consider a distance disparity among the receivers and incorporate a simple precoding which reveals the gains of RS. By taking into account spatial randomness, we provide closed form expressions for the coverage probabilities of each receiver and derive the average sum rate achieved with the employment of RS. We present numerical results that validate our analysis and show that RS brings significant performance gains compared to the well-known non-orthogonal multiple access scheme, while it consists of a general and more flexible scheme.