Blockage-Aware Flow Control in E-UTRA-NR Dual Connectivity for QoS Enhancement

Millimeter-wave (mmWave) communication included in new radio (NR) provides high throughput to meet the stringent requirements of modern applications. However, its performance is highly dependent on whether obstacles are blocking line-of-sight (LOS) paths. Blockages on the LOS paths jeopardize reliable connections. E-UTRA-NR dual connectivity (EN-DC) is one option for managing unstable connectivity using robust long-term evolution (LTE) as well as mmWave NR. EN-DC aggregates and utilizes multiple links to provide a better quality of service (QoS) to users. However, the performance of EN-DC is strongly affected by flow control due to the possibility of out-of-order packet delivery at the packet data convergence protocol (PDCP) layer. In this paper, we propose a blockage-aware flow control scheme (
BAFC
) that appropriately responds to the dynamics of mmWave links in the presence of mobile blockages and improves users’ QoS. To this end, we also develop PDCP scheduling schemes that satisfy various users’ QoS requirements. Through extensive simulations, we verify that
BAFC
exploits over 99% of the sum capacity of links on average under rapidly changing channels due to mobile blockages. Moreover,
BAFC
combined with PDCP scheduling achieves higher throughput or reduces latency by up to 43.9% with minimal throughput degradation.