Data pre-forwarding for opportunistic data collection in wireless sensor networks

Abstract

Opportunistic data collection in wireless sensor networks uses passing smartphones to collect data from sensor nodes, thus avoiding the cost of multiple static sink nodes. Based on the observed mobility patterns of smartphone users, sensor data should be preforwarded to the nodes that are visited more frequently with the aim of improving network throughput. In this article, we construct a formal network model and an associated theoretical optimization problem to maximize the throughput subject to energy constraints of sensor nodes. Since a centralized controller is not available in opportunistic data collection, data pre-forwarding (DPF) must operate as a distributed mechanism in which each node decides when and where to forward data based on local information. Hence, we develop a simple distributed DPF mechanism with two heuristic algorithms, implement this proposal in Contiki-OS, and evaluate it thoroughly. We demonstrate empirically, in simulations, that our approach is close to the optimal solution obtained by a centralized algorithm. We also demonstrate that this approach performs well in scenarios based on real mobility traces of smartphone users. Finally, we evaluate our proposal on a small laboratory testbed, demonstrating that the distributed DPF mechanism with heuristic algorithms performs as predicted by simulations, and thus that it is a viable technique for opportunistic data collection through smartphones.

Movement-Aware Relay Selection for Delay-Tolerant Information Dissemination in Wildlife Tracking and Monitoring Applications

“…For the Type-IV class, a maximum (or average) movement speed is estimated for the mobile node, so a circular movement range can be drawn to predict contact (as in [17] [18]), where the radius depends on the delay since the location report. For the Type-V class, with additional knowledge on movement direction, the location of future contact can be expected given the delay (such as in [19] [9]). However, the speed and direction are not enough to differentiate heterogeneous mobility, which limits the contact prediction based on the Type-IV/V mobility description.…”

“…When the value of σ is sufficiently small compared with the truncation bound ǫ, the truncated Normal distribution is very close to a Normal distribution without truncation. To measure the relationship between σ and ǫ, we define a ratio as ρ = ǫ σ (22) Then equation (19) can be written as…”

Using Mobile Elements as Dynamic Bridges in Sparse Wireless Sensor Networks

“…Data collection and data forwarding are essential functions of WSNs. In a sparse WSN, special mobile data collectors (MDCs) are used to gather data from ordinary sensor nodes [9,34,35]. MDCs can be either mobile sinks or mobile relays.…”

“…MDCs can be either mobile sinks or mobile relays. Another types of MEs are Mobile Relays (MRs) [9,34,35], which are support nodes to gather data from sensor nodes, store them and forward them to sinks or base stations. MR-based data collection in WSNs has been proposed in the data-MULE system [20].…”

Data Pre-Forwarding for Opportunistic Data Collection in Wireless Sensor Networks

“…To achieve the expected long network life, these sensor nodes must be aggressively duty cycled. For example, millions of water meters will be installed across the Republic of Ireland in the near future, and many air quality monitoring Preliminary results were presented at the 9th International Conference on Networked Sensing Systems (INSS 2012) [Wu et al 2012]. This work was supported in part by the Irish HEA PRTLI-IV NEMBES Grant and the CTVR Grant (SFI 10/CE/I 1853) from Science Foundation Ireland.…”