A Novel Transmission Scheme for the $K$ -User Broadcast Channel With Delayed CSIT

Abstract

The state-dependent $K$ -user memoryless broadcast channel (BC) with state feedback is investigated. We propose a novel transmission scheme and derive its corresponding achievable rate region, which, compared with some general schemes that deal with feedback, has the advantage of being relatively simple and thus is easy to evaluate. In particular, we show that the proposed scheme achieves the capacity region of the symmetric erasure BC with an arbitrary input alphabet size. For the fading Gaussian BC, numerical results show that the proposed scheme outperforms existing schemes in terms of symmetric rate. Our analysis also proves its optimality at high signal-to-noise ratio, in terms of degrees of freedom.