Aligned Virtual Coordinates for Greedy Routing in WSNs

Geographic routing protocols achieve relatively good performance, and provide several advantages over conventional protocols for multi-hop wireless networks. However, such protocols are impacted by physical voids, and localization errors. Virtual coordinate systems (VCS) were proposed as an alternative approach that is resilient to localization errors and that naturally routes around physical voids. In this paper, we show that VCS is vulnerable to different forms of the void problem and, in general, perform worse than geographic routing in the greedy phase. We show that these anomalies arise from quantization noise in the estimate of connectivity and node location due to the integral nature of VCS coordinates. We propose an aligned virtual coordinate system (AVCS) on which the greedy routing success can be significantly improved. With our approach, and for the first time, we show that greedy routing on VCS outperforms that on geographic coordinates even with no localization errors. We compare AVCS against some of the most popular geometric routing protocols both using physical and virtual coordinates and show that it significantly improves performance over these solutions