On Modeling Low-Power Wireless Protocols Based on Synchronous Packet Transmissions

Abstract

Abstract-Mathematical models play a pivotal role in understanding and designing advanced low-power wireless systems. However, the distributed and uncoordinated operation of traditional multi-hop low-power wireless protocols greatly complicates their accurate modeling. This is mainly because these protocols build and maintain substantial network state to cope with the dynamics of low-power wireless links. Recent protocols depart from this design by leveraging synchronous transmissions (ST), whereby multiple nodes simultaneously transmit towards the same receiver, as opposed to pairwise link-based transmissions (LT). ST improve the one-hop packet reliability to an extent that efficient multi-hop protocols with little network state are feasible.This paper studies whether ST also enable simple yet accurate modeling of these protocols. Our contribution to this end is twofold. First, we show, through experiments on a 139-node testbed, that characterizing packet receptions and losses as a sequence of independent and identically distributed (i.i.d.) Bernoulli trials-a common assumption in protocol modeling but often illegitimate for LT-is largely valid for ST. We then show how this finding simplifies the modeling of a recent ST-based protocol, by deriving (i) sufficient conditions for probabilistic guarantees on the end-toend packet reliability, and (ii) a Markovian model to estimate the long-term energy consumption. Validation using testbed experiments confirms that our simple models are also highly accurate; for example, the model error in energy against real measurements is 0.25%, a figure never reported before in the related literature.

End-to-End Real-Time Guarantees in Wireless Cyber-Physical Systems

“…Experiments on several large-scale testbeds show that the approach is highly adaptive and achieves an end-to-end packet reliability higher than 99.9 % [19], [20]. Furthermore, the few packet losses can be considered statistically independent [28], which eases the design of CPS controllers that can deal with intermittent observations [29]. Although our approach can be adapted to other types of communication protocols, the paper is based on this concept of synchronous transmissions.…”

Synchronous transmissions enable simple yet accurate protocol modeling

“…We found that the Bernoulli assumption is highly valid to ST and significantly more valid to ST than to LT, based on the following methodology (see [10] for more details). Methodology.…”

“…Recent protocols use synchronous transmissions (ST): multiple nodes send simultaneously towards the same receiver, as opposed to pairwise link-based transmissions (LT). ST enable efficient multi-hop protocols with little network state.We studied whether ST in Glossy enable simple yet accurate protocol modeling [10]. Based on extensive testbed experiments and statistical analyses, we found that: (i) unlike LT, packet receptions and losses with ST largely adhere to a sequence of independent and identically distributed (i.i.d.)…”

“…We studied whether ST in Glossy enable simple yet accurate protocol modeling [10]. Based on extensive testbed experiments and statistical analyses, we found that: (i) unlike LT, packet receptions and losses with ST largely adhere to a sequence of independent and identically distributed (i.i.d.)…”

P3: A Practical Packet Pipeline using synchronous transmissions for wireless sensor networks

“…While Marco Zimmerling et al have shown in [34] that it is largely valid to assume packet receptions under synchronous transmissions to be independent, their experiments are limited to Channel 26. As P 3 is a multi-channel system and one of its central requirements is that the independence must be true on at least four different channels, we carryout experiments to demonstrate that this requirement can be satisfied in practice.…”