Video streaming performance may degrade substantially in a mobile environment due to fast-changing wireless links. On the other hand, to provide ubiquitous services, heterogeneous static and mobile access and backbone networks will be integrated in the sixth-generation (6G) systems, so mobile users can take advantage of multiple access options for better services. Multi-path transport-layer protocols like Multi-Path QUIC (MPQUIC) show promise in utilizing multiple access links to address the impact of mobility. However, the optimal link selection that aims to provide statistical QoS guarantee for video streaming in a mobile environment with both user mobility and network mobility remains an open issue. In this paper, based on a lightweight Multi-Armed Bandit (MAB) technique, we develop aQoS-drivenContextualMAB(QC-MAB) framework for MPQUIC, which makes an intelligent access network selection and adaptively enables FEC coding to trade off delay, reliability and goodput. Extensive simulation results with ns-3 show that the proposed QC-MAB framework can outperform the state-of-the-art solutions. It achieves up to ten times lower video interruption ratio and three times higher goodput in highly dynamic mobile environments.

The Integrated Terrestrial and LEO Satellite Network (ITSN) has a high bandwidth-delay product (BDP) and high-speed movement, which makes congestion control difficult. We develop aMobility-AwareCOngestion control (MACO) algorithm for multipath QUIC (MPQUIC) in ITSN. MACO models the dynamic interactions between MPQUIC subflows and LEO networks, including handovers and outages triggered by satellite movement, and changes in network topology and link conditions. With the knowledge of network dynamics influenced by mobility, MACO can estimate changes in path BDP without solely relying on lengthy network probing. It employs a quick start (QS) and an effective congestion avoidance (CA) mechanism based on a multipath fluid model. The QS sets an appropriate initial cwnd to shorten the slow start duration. The CA applies a square root function to quickly increase the cwnd to the equilibrium and conservatively increase when approaching the BDP. We conduct a series of experiments to evaluate MACO using network simulator 3 (ns-3) based on collected data traces on Starlink. Simulation results demonstrate that MACO can achieve upto three times higher throughput and improve the convergence performance by 70.67% against benchmark algorithms.

Multi-homing technologies are promising to support seamless handoff and non-interrupted transmissions. Scheduling packets across multiple paths, however, has the known issue of out-of-order (OFO) due to the heterogeneity of the paths, which is detrimental to users’ quality of experience (QoE). Wireless link characteristics undergo a fast change over time in mobile environments, thus aggravating the OFO issue. In this paper, we present a novel mobility-aware multipath QUIC (MMQUIC) framework in which interactions between link and transport layers are introduced so that the scheduler at a mobile sender is aware of uplink variations, and a new ACK packet structure is designed to inform the scheduler of downlink variations when the receiver is mobile. Based on MMQUIC, a Mobility-Aware Multipath Scheduler (MAMS) is developed, which forecasts the path conditions in successive time slots based on historical and current end-to-end (E2E) path conditions, along with wireless uplink/downlink conditions, and pre-allocates packets on multiple paths accordingly. We conduct a series of experiments to evaluate the performance of MAMS using network simulator 3 (ns-3). Simulation results demonstrate that MAMS effectively leverages the information related to mobility, achieving substantial performance gains w.r.t. the goodput and packet delay distribution under different mobility patterns.

Multi-homing technologies are promising to support seamless user mobility, as a mobile device can use multiple access links and paths for non-interrupted transmissions. Scheduling packets across multiple paths, however, has the known issue of out-of-order (OFO) due to the heterogeneity of the paths. Mobility poses new challenges due to time-varying link quality and capacity. In this paper, we present a novel Mobility-aware Multipath Quick UDP Internet Connections (MMQUIC) framework which enables collaboration between the link and transport layer. Based on MMQUIC, we develop a Mobility-Aware Multipath Scheduler (MAMS) for goodput enhancement, in which the impacts of mobility such as link outage errors and capacity variations are considered. Finally, we evaluate the performance of MAMS using network simulator 3 (ns-3). Simulation results demonstrate that our design has substantial performance gains with respect to the goodput and packet delay distribution in dynamic wireless systems.

The Integrated Terrestrial and LEO Satellite Network (ITSN) is promising for providing ubiquitous communication services, which attracts attention but also brings new challenges. In this regard, a new transport layer protocol, Multipath QUIC (MPQUIC) appears salient advantages in tackling with the challenging environment (e.g., large propagation delays, high-speed mobility, etc.). However, the standard congestion control algorithm of MPQUIC, Opportunistic Linked Increases Algorithm (OLIA), still encounters great challenges such as congestion window (cwnd) overshooting whenever handoff, which motivates our proposal, a Mobility-aware Multipath QUIC (MM-QUIC) congestion control algorithm. MM-QUIC leverages the periodical changes of path capacity and good similarity among disjoint subflows to quickly start a new round of transmission, and employs a multipath-based fluid model to determine the cwnd adjustment in the congestion avoidance phase. Finally, simulation results on NS-3 demonstrate that MM-QUIC can offer up to 50% throughput improvement compared to OLIA in ITSN.