SLACK-MAC: Adaptive MAC Protocol for Low Duty-Cycle Wireless Sensor Networks

Abstract

Wireless sensor networks (WSNs) are increasingly used in environmental monitoring applications. They are designed to operate for several months by featuring low activity cycles, in order to save energy. In this paper, we propose a MAC protocol for such WSNs with duty-cycles of 1%. Initially, nodes are activated randomly and independently, then they use the knowledge of previous successful frame exchanges to compute their next activation times. We study the choice of the history size, and we compare the performance of our protocol with other protocols from the literature. We show that with a limited history size of only six entries, we significantly improve the performance of existing protocols, while keeping the advantages of fully asynchronous protocols.

History-based MAC Protocol for Low Duty-Cycle Wireless Sensor Networks: the SLACK-MAC Protocol

“…SLACK-MAC was initially presented in [5]. The main idea of SLACK-MAC is to maintain a history of instants corresponding to successful communications with neighbors.…”

“…In this paper, we present the SLACK-MAC (Self-adaptive Low Activity Cycle Knowledge-based MAC) protocol (extended version of [5]), which is an asynchronous protocol where nodes activate their radio modules randomly. The idea behind SLACK-MAC is inspired by the routing protocol proposed in [6], where authors proposed the SR3 protocol, which is an improvement over a biased random walk * Affoua Thérèse Aby.…”

“…In this paper, we show that this behavior improves the probability of successful communications, which in turn improves the performance in terms of delivery rate and delay. This paper is an extended version of [5]. It improves the description of [5] on several aspects, including mainly: (i) an experimental evaluation of SLACK-MAC using TelosB motes, (ii) new simulation results comparing SLACK-MAC with additional asynchronous protocols from the literature [7,8], and (iii) the energy consumption as a new metric.…”

Impact of the simulation parameters on the quantitative results of protocols for WSNs

“…In asynchronous duty cycle MAC protocols, nodes do not have a common calendar for their activity and sleep periods. This is the case of X-MAC [9], OSX-MAC [10], RI-MAC [11], HKMAC [12], AaaMAC [13] and SlackMAC [14], [15]. In these protocols quantitative results of simulations comparing them with other existing protocols are given.…”

“…We show, for instance that the value of the capture threshold and the main parameters (path loss exponent and the standard deviation) of a realistic propagation model as log-shadowing have significant effects on the quantitative results. To do this, we use an asynchronous MAC protocol that we proposed SlackMAC [14], [15] which was compared with the reference synchronous MAC protocol specified in the standard IEEE 802.15.4 [5] in beacon enabled mode. This choice is justified by the fact that we intuitively know the result of this comparison, we will try to show the diversity of results by intensive simulations.…”