How do Wireless Chains Behave? The Impact of MAC Interactions

TL;DR

This paper investigates how MAC interactions influence the behavior of multi-hop wireless chains, revealing that destructive interactions increase bandwidth consumption but do not significantly affect throughput, with implications for network performance.

Contribution

It provides a detailed analysis of MAC-level interactions in wireless chains, highlighting the impact of hidden terminal effects and chain interference on network efficiency.

Findings

Destructive MAC interactions increase bandwidth usage.

Hidden terminal effects do not significantly reduce chain throughput.

Self-interference resilience improves chain robustness.

Abstract

In a Multi-hop Wireless Networks (MHWN), packets are routed between source and destination using a chain of intermediate nodes; chains are a fundamental communication structure in MHWNs whose behavior must be understood to enable building effective protocols. The behavior of chains is determined by a number of complex and interdependent processes that arise as the sources of different chain hops compete to transmit their packets on the shared medium. In this paper, we show that MAC level interactions play the primary role in determining the behavior of chains. We evaluate the types of chains that occur based on the MAC interactions between different links using realistic propagation and packet forwarding models. We discover that the presence of destructive interactions, due to different forms of hidden terminals, does not impact the throughput of an isolated chain significantly. However, due to the increased number of retransmissions required, the amount of bandwidth consumed is significantly higher in chains exhibiting destructive interactions, substantially influencing the overall network performance. These results are validated by testbed experiments. We finally study how different types of chains interfere with each other and discover that well behaved chains in terms of self-interference are more resilient to interference from other chains.