Addressing Anomalies in Geometric Routing

Geographic routing protocols have attracted interest in multi-hop wireless networks due to their ability to achieve good performance in the Greedy Forwarding (GF) mode at much lower overhead than conventional routing protocols such as DSR or DSDV. However, the performance of these protocols is impacted by physical voids, where a node has no neighbors closer than itself to the destination. Voids require a complimentary algorithm to traverse them; such algorithm typically has high overhead and results in lower quality paths. Geographic routing protocols are sensitive to localization errors which could lead to inefficient routes or even misrouting of packets. Accordingly, virtual coordinate systems (VCS) were proposed to be an alternative solution that is resilient to localization errors and naturally traverses physical anomalies. However, we show that VCS is vulnerable to different forms of anomalies and the performance of greedy routing on VCS is worse than that on physical coordinate systems. We analyze anomalies in VCS with different dimensions, and explain the reasons behind the anomalies.