Joint of full-duplex relay, non-linear energy harvesting and multiple access in performance improvement of cell-edge user in heterogeneous networks

To serve massive connections in heterogeneous networks with respect to higher energy efficiency, we focus on new paradigm in order to achieve multiple access and performance improvement at cell-edge area. The power domain based non-orthogonal multiple access is introduced to address such problem. In particular, this paper studies a self-energy relay together with full-duplex scheme to implement cooperative power domain based non-orthogonal multiple access in small-cell system of the heterogeneous networks. In such small-cell network, a nearby user can be employed as a decode-and-forward with self-energy recycling protocol to assist a far power domain based non-orthogonal multiple access user (cell-edge user). The relay harvests energy from dedicated energy signal sent by a base station, while it still reuses energy from loop self-interference signal. To characterize the performance of the proposed system with respect to where meets weak signal condition, numerous expressions of exact outage probability for far power domain based non-orthogonal multiple access user is derived. Several practical scenarios are performed in three different schemes related to how energy harvesting architecture can be achieved. Based on analytical results, the optimal throughput achieved by the cell-edge user in small-cell network can be observed. Numerical results are presented to validate the accuracy of the derived results.