Latency-and-Coverage Aware Data Aggregation Scheduling for Multihop Battery-Free Wireless Networks

• Published in: IEEE transactions on wireless communications Vol. 20; no. 3; pp. 1770 - 1784
• Main Authors: Cai, Zhipeng, Chen, Quan
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.03.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Agglomeration; Algorithms; battery-free; Collision avoidance; Communication; Data aggregation; Data management; Heuristic algorithms; Internet of Things; latency-and-coverage aware; multiple channels; Network latency; Nodes; Schedules; Task analysis; Task scheduling; Wireless networks; Wireless sensor networks
• ISSN: 1536-1276; 1558-2248
• DOI: 10.1109/TWC.2020.3036408

Battery-Free Wireless Sensor Networks (BF-WSNs) have been attracting increasing interests in the recent years. To reduce the latency in BF-WSNs, the Minimum Latency Aggregation Scheduling (MLAS) problem with coverage requirement <inline-formula> <tex-math notation="LaTeX">q </tex-math></inline-formula> is proposed recently, which tries to choose <inline-formula> <tex-math notation="LaTeX">q </tex-math></inline-formula> percent of nodes for communication and aggregation. In the existing method, the authors try to select nodes adaptively according to their energy status and schedule these nodes to achieve the minimum latency. Unfortunately, it cannot guarantee the distribution of the aggregated nodes and may result in these nodes being squeezed in a small area and a poor aggregation quality. Thus, we re-investigate the <inline-formula> <tex-math notation="LaTeX">q </tex-math></inline-formula>-coverage MLAS problem in this article, which can guarantee that the aggregated nodes are distributed evenly. Firstly, the 1-coverage MLAS problem, in which each node can be covered by at least one aggregated node, is studied. To reduce the latency, we intertwine the selection of aggregated nodes and the computation of a collision-free communication schedule simultaneously. Two algorithms are proposed by scheduling the communication tasks in the bottom-up and top-down manner respectively. Secondly, to satisfy the arbitrary coverage requirement <inline-formula> <tex-math notation="LaTeX">q </tex-math></inline-formula>, three algorithms are proposed to guarantee the aggregated nodes are evenly distributed in the network with a low latency. Additionally, the method to extend the proposed algorithms for the BF-WSNs with multiple channels is also studied. The theoretical analysis and simulation results verify that the proposed algorithms have high performance in terms of latency.