On the Performance Evaluation of Enabling Architectures for Uplink and Downlink Decoupled Networks

The road to 5G is posing challenging requirements to the cellular network to introduce more applications from several industry verticals. Low delay, high scalability, ultra-reliability and device-centric procedures are some of these requirements. Decoupled Uplink (UL) and Downlink (DL), DUDe, is a key enabler of the device-centric network, and provides a good solution to the UL and DL imbalance problem in heterogeneous networks, improving the UL reliability and load balancing. However, the direct applicability of this technique in 4G networks is subject to either very low backhaul latency between both cooperative base stations, or assisting UL and DL connections that can carry the user plane control signals. This article does a comprehensive study of the enabling architectures for DUDe; the proposed architectures are based on two well- known techniques, Dual Connectivity and Cloud Radio Access Networks. The impact of high latency fronthaul and X2 interfaces is studied and compared to the upper bound UL reliability and throughput obtained with regular round trip time (RTT) values. Results show that even if the radio access network RTT is doubled, DUDe provides an improvement in the UL reliability compared to the classical DL received power cell association.