On efficiency and validity of previous Homeplug MAC performance analysis

Abstract

The Medium Access Control protocol of Power Line Communication networks (defined in Homeplug and IEEE 1901 standards) has received relatively modest attention from the research community. As a consequence, there is only one analytic model that complies with the standardised MAC procedures and considers unsaturated conditions. We identify two important limitations of the existing analytic model: high computational expense and predicted results just prior to the predicted saturation point do not correspond to long-term network performance. In this work, we present a simplification of the previously defined analytic model of Homeplug MAC able to substantially reduce its complexity and demonstrate that the previous performance results just before predicted saturation correspond to a transitory phase. We determine that the causes of previous misprediction are common analytical assumptions and the potential occurrence of a transitory phase, that we show to be of extremely long duration under certain circumstances. We also provide techniques, both analytical and experimental, to correctly predict long-term behaviour and analyse the effect of specific Homeplug/IEEE 1901 features on the magnitude of misprediction errors.

On the MAC for Power-Line Communications: Modeling Assumptions and Performance Tradeoffs

“…We next show that there exists only one value of p e that satisfies (8). Due to space constraints, we show in [16] that Φ(p e ) has at least one fixed-point.…”

“…Finally, Cano and Malone [8] provide a simplification of the analysis of [6] for computing the delay under unsaturated traffic scenarios and discuss the assumptions used in [6]. Here too, their analysis relies on the decoupling assumption.…”

“…Moreover, as we explain in more details later, the use of the deferral counter introduces some level of coupling between the stations, which penalizes the accuracy of models based on the decoupling assumption. This assumption was originally proposed in the 802.11 analysis of [5] and has been used in all the works that have analyzed the 1901 CSMA/CA procedure so far (i.e., [6], [7], [8]). In this paper, we show that this decoupling assumption leads to inaccurate results, and the modeling accuracy can be substantially improved by avoiding it.…”

Analyzing and Boosting the Performance of Power-Line Communication Networks

“…To the best of our knowledge, the only works analyzing the backoff process of 1901 are [12,11,20,19]. The authors in [12] propose a model similar to Bianchi's model for 802.11 [8].…”

“…Moreover, it has not been investigated whether this system of equations has a unique solution. The work in [11] discusses the validity of the decoupling assumption and simplifies the model in [12] in the case the stations are not saturated. Here again, the authors do not investigate the uniqueness of the solution(s) of their model.…”