Link Quality Estimation in Ad Hoc and Mesh Networks: A Survey and Future Directions

Higher layer applications, such as routing protocols and robot navigation systems, commonly depend upon link quality (LQ) estimates for improving the efficiency and reliability of wireless communications. LQ estimation is especially critical for maintaining connectivity in mobile ad hoc networks, which tend to be less reliable than infrastructure networks due to their decentralized and dynamic nature. However, estimating LQ for applications higher than the physical layer is challenging due to the underlying dynamics of wireless propagation and the mismatched temporal perspectives between the layers. Due to its relevance and difficulty, a significant research effort has been devoted to developing empirical methods for accurately estimating LQ. The goal of this survey is to provide a comprehensive review of the existing approaches to LQ estimation in IEEE 802.11-based ad hoc and mesh networks, with some exceptions that include sensor networks. The survey organizes the literature according to the different fundamental techniques, and also compares them in terms in terms of strengths and weaknesses. Finally, we conclude with the latest developments in LQ estimation, which involve machine learning, and provide recommendations for future work in the field.