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Delay Guarantees for a Swarm of Mobile Sensors in Safety-Critical Applications

Azuaje, O. ; Aguiar, A.

IEEE Open Journal of the Communications Society Vol. 5, Nº , pp. 7147 - 7159, , 2024.

ISSN (print):
ISSN (online): 2644-125X

Scimago Journal Ranking: 2,71 (in 2023)

Digital Object Identifier: 10.1109/OJCOMS.2024.3491947

Abstract
Swarms of mobile wireless-connected sensors are increasingly deployed for applications such as monitoring, surveillance, and safety-critical operations. Quantifying end-to-end (e2e) delay performance guarantees in these scenarios is paramount. In this paper, we present a theoretical approach using Stochastic Network Calculus (SNC) with Moment Generating Functions (MGFs) to characterize e2e delay bounds in Mobile Wireless Sensor Networks (MWSNs). Our study focuses on a network composed of two segments: the first segment includes multiple nodes connected via a contention-based channel using the Distributed Coordination Function (DCF), while the second segment consists of a link prone to disconnections due to the mobility of nodes in the first segment. We model the first segment by calculating the expected per-packet service time in a non-saturated homogeneous contention channel and the second segment using a Discrete Time Markov Chain (DTMC). Initially, we derive a mathematical expression that correlates the offered load with the saturation status of each node’s queue in a non-saturated contention channel with homogeneous nodes. We then provide numerical e2e delay bounds for an illustrative example of a first responder network, quantifying the effects of non-saturated traffic, communication range on the head-sink link, and scheduling algorithms across different network sizes. Finally, we compare the derived e2e delay bounds with network simulations to assess their accuracy and reliability.