Generalizing Biased Backpressure Routing and Scheduling to Wireless Multi-hop Networks with Advanced Air-interfaces

2025-04-30

AI Summary

This work addresses critical limitations of conventional biased back-pressure (BP) routing in wireless multihop MIMO networks—including slow start-up, random walk behavior, the “last-packet problem,” low bandwidth utilization, and routing loops/deflections caused by redundant link scheduling. We propose a novel distributed resource coordination mechanism. Our approach features: (1) a non-exclusive Max-Utility link-sharing scheduler, departing from traditional exclusive link selection; (2) the Attribute-based Capacity Hypergraph (ACH) model, the first to capture high-dimensional interference relationships among MIMO links; and (3) a dynamic queue-state redistribution mechanism for load balancing. Leveraging Lyapunov drift theory and generalized MaxWeight analysis, our method significantly mitigates the last-packet problem under light load, marginally expands the network capacity region under heavy load, and improves both link utilization and routing stability.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Multiagent Systems: Mechanism Design
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization

Application Category

• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• Systems and Infrastructure for Web, Mobile and WoT: Virtualization and resource management in Web systems and infrastructures
• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems

Abstract

Backpressure (BP) routing and scheduling is a well-established resource allocation method for wireless multi-hop networks, known for its fully distributed operations and proven maximum queue stability. Recent advances in shortest path-biased BP routing (SP-BP) mitigate shortcomings such as slow startup and random walk, but exclusive link-level commodity selection still suffers from the last-packet problem and bandwidth underutilization. Moreover, classic BP routing implicitly assumes single-input-single-output (SISO) transceivers, which can lead to the same packets being scheduled on multiple outgoing links for multiple-input-multiple-output (MIMO) transceivers, causing detouring and looping in MIMO networks. In this paper, we revisit the foundational Lyapunov drift theory underlying BP routing and demonstrate that exclusive commodity selection is unnecessary, and instead propose a Max-Utility link-sharing method. Additionally, we generalize MaxWeight scheduling to MIMO networks by introducing attributed capacity hypergraphs (ACH), an extension of traditional conflict graphs for SISO networks, and by incorporating backlog reassignment into scheduling iterations to prevent redundant packet routing. Numerical evaluations show that our approach substantially mitigates the last-packet problem in state-of-the-art (SOTA) SP-BP under lightweight traffic, and slightly expands the network capacity region for heavier traffic.

Problem

• Improving backpressure routing to address last-packet and bandwidth issues
• Extending BP routing to MIMO networks to prevent detouring and looping
• Proposing Max-Utility link-sharing and ACH for better network performance

Innovation

• Proposes Max-Utility link-sharing for commodity selection
• Introduces attributed capacity hypergraphs for MIMO
• Incorporates backlog reassignment to prevent redundancy