  Millimeter wave (mmWave) access networks have the potential to meet the
high-throughput and low-latency needs of immersive applications. However, due
to the highly directional nature of the mmWave beams and their susceptibility
to beam misalignment and blockage resulting from user movements and rotations,
the associated mmWave links are vulnerable to large channel fluctuations. These
fluctuations result in disproportionately adverse effects on performance of
transport layer protocols such as Transmission Control Protocol (TCP). To
overcome this challenge, we propose a network layer solution, COded Taking And
Giving (COTAG) scheme to sustain low-latency and high-throughput end-to-end TCP
performance in dually connected networks. In particular, COTAG creates network
encoded packets at the network gateway and each access point (AP) aiming to
adaptively take the spare bandwidth on each link for transmission. Further, if
one link bandwidth drops due to user movements, COTAG actively abandons the
transmission opportunity by conditionally dropping packets. Consequently, COTAG
actively adapts to link quality changes in mmWave access network and enhances
the TCP performance without jeopardizing the latency of immersive content
delivery. To evaluate the effectiveness of the proposed COTAG, we conduct
experiments using off-the-shelf APs and network simulations. The evaluation
results show that COTAG improves end-to-end TCP performance significantly on
both throughput and latency.

Signal Processing