Evolving LTE with Flexible Duplex

Both TDD and FDD systems obtain their own merits and application limit. As the increasing of service requirement and traffic load, more and more telecommunication systems are operating in both FDD and TDD bands. It is foreseen that convergence of TDD and FDD will be the evolution trend of mobile communication systems. The paper proposes Flexible Duplex to enhance network efficiency and flexibility to well support non-uniform and varying traffic as well as various scenarios adaptively, which is the most important phase of the duplex evolution roadmap. With flexible duplex, those resources reserved for UL (DL) in conventional system can be re-allocated for DL (UL) with high flexibility. Based on the LTE system, seen as the global common 4G system, the system design to support flexible duplex is interpreted, characterized in the symmetrical DL/UL transmission to enable the inter-direction interference cancellation and simplify the receiver complexity. Several scenarios can benefit from the technique and evident gain is proved with simulation results.