Coordinated rate splitting and power allocation in energy-spectral efficiency tradeoff-based multicell networks

Abstract

In order to support the energy efficiency (EE) and spectral efficiency (SE) in beyond 5G (B5G) wireless communication networks, we propose a flexible tradeoff design of these key performance metrics to obtain simultaneous EE and SE performance enhancement compared to conventional investigations where EE and SE are optimized independently. In this paper, a multi-objective optimization problem (MOOP) in the coordinated rate splitting (Co-RS) based multicell network is formulated to jointly optimize the private power, the coordinated common power and the common rate, by which both network EE and SE can be simultaneously achieved under the consideration of estimated channel error. To make the formulated MOOP tractable, we first transform the independent EE and SE maximization MOOP into a EE and SE tradeoff based single-objective optimization problem (SOOP) equivalently by introducing a flexible weight parameter. Then, fractional optimization is used to handle the multi-ratio objective function, by which an alternative optimization (AO) based sub-optimal solution is proposed to optimize the private power allocation, the joint common power and the spitted rate allocation iteratively with guaranteed convergence. Numerical results have demonstrated that the proposed Co-RS framework is able to achieve flexible EE-SE tradeoff in the multicell network, where better tradeoff has been achieved compared to the related benchmarks.