Dual connectivity for LTE-advanced heterogeneous networks

Dual connectivity (DC) allows user equipments
(UEs) to receive data simultaneously from different eNodeBs
(eNBs) in order to boost the performance in a
heterogeneous network with dedicated carrier deployment.
Yet, how to efficiently operate with DC opens a number of
research questions. In this paper we focus on the case
where a macro and a small cell eNBs are inter-connected
with traditional backhaul links characterized by certain
latency, assuming independent radio resource management
(RRM) functionalities residing in each eNB. In order to
fully harvest the gain provided by DC, an efficient flow
control of data between the involved macro and small cell
eNBs is proposed. Moreover, guidelines for the main performance
determining RRM algorithms such as UE cell
association and packet scheduling are also presented. It is
demonstrated how proper configuration of the proposed
flow control algorithm offers efficient trade-offs between reducing the probability that one of the eNBs involved in the DC runs out of data and limiting the buffering time.
Simulation results show that the performance of DC over traditional backhaul connections is close to that achievable with inter-site carrier aggregation (CA) and virtually zerolatency fronthaul connections, and in any case it is significantly
higher compared to the case without DC.
Keywords: Dual connectivity Heterogeneous network LTE-advanced Radio resource management Performance evaluation