Bandwidth Aggregation for Urban Rail Transit Based on Multi-path Transmission

［Objective］ Urban rail transit widely adopts the LTE-M (long-term evolution for metro) system to support various services. However, with the rapid growth of video data traffic, the system faces increasing bandwidth pressure. To address this challenge, a multi-path transmission system tailored to the urban rail transit network environment needs to be designed to aggregate multiple network bandwidths. ［Method］ Based on the MPQUIC (multipath quick UDP (user datagram protocol) internet connections) protocol, a dynamic redundancy-based multi-path transmission system for urban rail transit is designed. The system incorporates two transmission modes. Under regular conditions, to minimize time differences in data transmission across paths, a pre-allocated packet-based multi-path scheduling algorithm is used. This approach mitigates the impact of network heterogeneity on transmission performance, making it more adaptable to heterogeneous network environments. Under cross-section handover conditions, to address the challenge of network fluctuations in mobility scenario caused by cross-section handover degrading transmission performance, the system determines switching between parallel scheduling and redundant scheduling at the signaling level, transitioning to redundant transmission in time to ensure stable performance during handover. The system architecture and scheduling algorithm design are introduced, and simulation experiments are conducted for validation. ［Result & Conclusion］ In simulated urban rail transit network scenarios, the proposed multi-path scheduling methods—combining redundancy and pre-allocation—demonstrates superior performance compared to the lowest RTT (round trip time) priority scheduling method. Under both favorable and poor network conditions, the average network throughput increases by 28.7% and 33.9%, respectively, validating the effectiveness and superiority of the designed dynamic redundancy-based multi-path transmission system for urban rail transit.