Dual Connectivity for LTE-NR Cellular Networks: Challenges and Open Issues

Abstract

The Dual Connectivity (DC) technology has gained a lot of momentum in the LTE Release 12 as a means to enhance the per-user throughput and provide mobility robustness. Some studies in the literature have discussed the interworking between the LTE and the air interface of the upcoming Fifth Generation (5G) in a DC scenario. That integration may provide some benefits to meet the high throughput, reliability and availability requirements of the 5G networks. This work firstly presents a brief overview of the DC technology considering the integration between 4G e 5G. Then, we highlight some open issues and challenges for future investigation involving Radio Resource Management (RRM) in such a scenario, which includes: (i) user-cell association, (ii) interaction between base stations and (iii) resource allocation. After that, we propose an extension of a utility-based resource allocation algorithm for DC scenarios. Finally, a performance evaluation is conducted in multi-Radio Access Technology (RAT) LTE-NR scenarios considering the bearer split configuration of the DC technology, where the gains provided by the proposed algorithm are demonstrated.

Unified Scheduling Framework for Dual Connectivity in Multi-RAT NSA 5G Networks

“…Table I summarizes the adopted parameters used for setting the simulation environment. For more details about the simulation environment, see [2], [11]. We compare our solution with: 1) a baseline framework with the UBA algorithm from [3], the FCA from [8] and the PF RRA algorithm for DC [13]; 2) the joint UBA and RRA solution from [16] with the FCA from [8]; and 3) the solution from [16] with the FCA from [11].…”

“…Fully harvesting the gains provided by DC in bearer split NSA 5G scenarios involves the design of three main functionalities [2]: i) a mechanism for the UD-BS association (UBA); ii) a flow control algorithm (FCA) for splitting the data traffic between BSs; and iii) radio resource management (RRM) techniques, such as radio resource allocation (RRA) and power control.…”

Dual connectivity for LTE-NR cellular networks in evolved packet system and critical review on challenges in SgNB release

“…Regarding this flow control mechanism, some studies exist for intra LTE DC in [14][15][16][17][18] that could be used as basis for LTE-NR DC. In [19] an overview of the work done in this area for LTE-NR DC can be found.…”

Dual Connectivity in Non-Stand Alone Deployment mode of 5G in Manhattan Environment

“…In dual connected mode the UE leverages benefits from both the LTE and 5G system, and the UE is connected to the LTE eNodeB (LTE-eNB) a.k.a Master eNB (MeNB) and 5G gNodeB (5G-gNB) a.k.a Secondary eNB (SeNB) simultaneously as shown in Fig .1. The LTE and 5G NR layers are aggregated via X2 interface between LTE eNB and 5G NR gNB [4]. One of the objective of the dual connectivity configuration is to provide system reliability for control information by utilizing the LTE coverage from the lower band and diminish the coverage interruptions that might occur at mid band or high band i.e.…”

“…The LTE-5G tight integration architecture for dual connectivity in NSA mode is shown in Fig. 1, it is also frequently called as "architecture configuration 3" [4], [6]. In this configuration, there is a bearer split at MeNB, and therefore there exists only a single bearer for each UE in dual connectivity mode, and the flow split occurs at MeNB.…”