High Throughput and Low Complexity Traffic Splitting Mechanism for 5G Non-Stand Alone Dual Connectivity Transmission

Abstract

Dual connectivity (DC) is a key technology to improve the throughput of the fifth generation communication networks (5G) system. Due to the limitation of the splitting strategy and transmission delay of different transmission nodes, the out-of-order phenomenon of the packet data convergence protocol (PDCP) layer is bound to occur in the actual DC system. Packet out-of-order in PDCP layer will affect the end-to-end throughput of PDCP layer and there is no effective solution at present. Existing schemes either neglected to consider the transmission rate difference between New Radio (NR) Base Station (BS) and Long Term Evolution-Advanced (LTE-A) BS, or performed unified modeling for queuing dynamics, or did not consider the existence of Xn delay, thus failing to model the out-of-order problem of PDPC layer. In this paper, we modeling PDCP out-of-order into a hierarchical model and continuously reduce the maximum out-of-order depth through recursion. Two traffic splitting mechanisms are proposed based on user equipment (UE) feedback and BS observation. These two low complexity traffic splitting mechanisms both show efficient link resource utilization ratio of more than 90% in static and mobile user scenarios, and are superior to conventional algorithms.