On real-time capacity of event-driven data-gathering sensor networks

Abstract

Network capacity is a critical feature of wireless ad hoc and sensor networks. It is particularly challenging to determine network capacity when combined with other performance objectives such as timeliness. This paper investigates real-time capacity for event-driven data-gathering sensor networks with the unbalanced many-to-one traffic pattern. First, we compute the average allowable throughputs of nodes for a given event distribution, based on which we then leverage results of queuing theory to estimate the per-hop delays. We develop a new slack time distribution scheme for the unbalanced many-to-one traffic pattern, and prove it optimal in terms of the per-hop success probability. Here the per-hop success probability is defined as the probability for a packet to meet its sub-deadlines at each hop. Finally, we define the network-wide real-time capacity, i.e., given a threshold for the per-hop success probability, how much data (in bit per second) can be delivered to the sink node meeting their deadlines. For these research results, we provide some application scenarios, including configuring packet deadlines or verifying a specific deadline configuration, setting a packet's priority for dynamic scheduling, and trading the reliability of real-time data delivery for capacity efficiency etc. We also study two special cases of WSNs, the chain model and the continuous model. Our slack distribution scheme yields consistent or similar results for these two special cases as that of past works, but is more adaptive by supporting more generic cases.

Packet Scheduling for Real-Time Surveillance in Multihop Wireless Sensor Networks With Lossy Channels

“…There has also been a lot of work that considers endto-end delay guarantees for wireless sensor networks. Jiang, Ravindran, and Cho [12] have studied the real-time capacity of wireless sensor networks. They approach this problem by decomposing end-to-end delays into per-hop delays, and then study the probability for meeting each per-hop delay independently.…”

Providing End-to-End Delay Guarantees for Multi-hop Wireless Sensor Networks over Unreliable Channels

“…There has also been a lot of work that considers endto-end delay guarantees for wireless sensor networks. Jiang, Ravindran, and Cho [12] have studied the realtime capacity of wireless sensor networks. They approach this problem by decomposing end-to-end delays into per-hop delays, and then study the probability for meeting each per-hop delay independently.…”

A Transmission Scheduling for Data-Gathering Wireless Sensor Networks

“…Usually such a network is modelled so that the sensor nodes are deployed into a boundary-limited area with the sink node(s) located at the center or border of the area. [1]- [3] There are several critical metrics in such a WSN configuration. Firstly, in order to maximize the network lifetime, the sensor nodes usually wake up to sense and transmit intermittently, and turn back to sleep for the rest of time to reduce battery dissipation.…”