Modeling IEEE 802.15.4 Networks over Fading Channels

TL;DR

This paper presents an analytical model for IEEE 802.15.4 networks over fading channels, revealing how fading impacts MAC performance and can sometimes improve network efficiency by reducing interference.

Contribution

It introduces a novel cross-layer analytical model considering fading, interference, hidden terminals, and MAC sensing limitations, advancing understanding of real-world wireless network behavior.

Findings

Fading can reduce multiple access interference, improving network performance.

MAC performance over fading channels differs significantly from ideal assumptions.

Joint MAC and physical layer parameter optimization is possible based on fading effects.

Abstract

Although the performance of the medium access control (MAC) of the IEEE 802.15.4 has been investigated under the assumption of ideal wireless channel, the understanding of the cross-layer dynamics between MAC and physical layer is an open problem when the wireless channel exhibits path loss, multi-path fading, and shadowing. The analysis of MAC and wireless channel interaction is essential for consistent performance prediction, correct design and optimization of the protocols. In this paper, a novel approach to analytical modeling of these interactions is proposed. The analysis considers simultaneously a composite channel fading, interference generated by multiple terminals, the effects induced by hidden terminals, and the MAC reduced carrier sensing capabilities. Depending on the MAC parameters and physical layer thresholds, it is shown that the MAC performance indicators over fading channels can be far from those derived under ideal channel assumptions. As novel results, we show to what extent the presence of fading may be beneficial for the overall network performance by reducing the multiple access interference, and how this can be used to drive joint selection of MAC and physical layer parameters.