Node-based Service-Balanced Scheduling for Provably Guaranteed Throughput and Evacuation Time Performance

This paper focuses on the design of provably efficient online link scheduling algorithms for multi-hop wireless networks. We consider single-hop traffic and the one-hop interference model. The objective is twofold: 1) maximizing the throughput when the flow sources continuously inject packets into the network, and 2) minimizing the evacuation time when there are no future packet arrivals. The prior work mostly employs the link-based approach, which leads to throughput-efficient algorithms but often does not guarantee satisfactory evacuation time performance. In this paper, we propose a novel Node-based Service-Balanced (NSB) online scheduling algorithm. NSB aims to give scheduling opportunities to heavily congested nodes in a balanced manner, by maximizing the total weight of the scheduled nodes in each scheduling cycle, where the weight of a node is determined by its workload and whether the node was scheduled in the previous scheduling cycle(s). We rigorously prove that NSB guarantees to achieve an efficiency ratio no worse (or no smaller) than 2/3 for the throughput and an approximation ratio no worse (or no greater) than 3/2 for the evacuation time. It is remarkable that NSB is both throughput-optimal and evacuation-time-optimal if the underlying network graph is bipartite. Further, we develop a lower-complexity NSB algorithm, called LC-NSB, which provides the same performance guarantees as NSB. Finally, we conduct numerical experiments to elucidate our theoretical results.