  Quite a few algorithms have been proposed to optimize the transmission
performance of Multipath TCP (MPTCP). However, existing MPTCP protocols are
still far from satisfactory in lossy and ever-changing networks because of
their loss-based congestion control and the difficulty of managing multiple
subflows. Recently, a congestion-based congestion control, BBR, is proposed to
promote TCP transmission performance through better use of bandwidth. Due to
the superior performance of BBR, we try to boost MPTCP with it. For this
propose, coupled congestion control should be redesigned for MPTCP, and a
functional scheduler able to effectively make use of the characteristics of BBR
must also be developed for better performance. In this paper, we first propose
Coupled BBR as a coupled congestion control algorithm for MPTCP to achieve high
throughput and stable sending rate in lossy network scenarios with guaranteed
fairness with TCP BBR flows and balanced congestion. Then, to further improve
the performance, we propose an Adaptively Redundant and Packet-by-Packet
(AR\&P) scheduler, which includes two scheduling methods to improve
adaptability in highly dynamic network scenarios and keep in-order packet
delivery in asymmetric networks. Based on Linux kernel implementation and
experiments in both testbed and real network scenarios, we show that the
proposed scheme not only provides higher throughput, but also improves
robustness and reduces out-of-order packets in some harsh circumstances.
