Affiliations: Software Engineering Institute and State Key Lab of
ISN, Xidian University, Xi'an, Shaanxi 710071, P.R. China | Department of Computer Science, Wayne State
University, Detroit, MI 48202, USA
Abstract: Recent studies in wireless sensor networks (WSNs) have observed that
the irregular link quality is a common phenomenon, rather than an anomaly. The
irregular link quality, especially link asymmetry, has significant impacts on
the design of WSN protocols. In this paper, we propose two asymmetry-aware link
layer services, including the neighborhood link quality service (NLQS)
and the link relay service (LRS). The novelty of the NLQS service is
taking the link asymmetry into consideration, providing timeliness link quality
and distinguishing the inbound and outbound neighbors with the support of LRS,
which builds a relay framework to alleviate the effects of link asymmetry. To
demonstrate the proposed link layer service, we design and implement two
example applications, building the shortest-hop routing path (SHRT) and
the best path reliability routing path (BRRT), on the TinyOS platform. We
found that the performance of two example applications is improved
substantially. More than 40% of nodes identify more outbound neighbors and the
percentage of increased outbound neighbors is between 14% and 100%. In SHRT,
more than 15% of nodes reduce hops of the routing path and the percentage of
reduced hops is between 14% and 100%. In BRRT, more than 16% of nodes
improve the path reliability of the routing path and the percentage of the
improved path reliability is between 2% to 50%.
Keywords: Neighborhood link quality service, link relay service, shortest-hop routing path, best path reliability routing path
