In a heterogeneous ad hoc network, assorted deviceswith different computation and communicationcapabilities co-exist and the links are asymmetric.Most MAC layer and routing protocols for ad hocnetworks routinely assume that all links aresymmetric and are unable to exploit the asymmetriclinks present in a network, thus leading to aninefficient bandwidth utilization, or, in the worstcase, to lack of connectivity. To exploit theasymmetric links, the protocols must deal with theasymmetry of the path from a source node to adestination node which affects either the delivery ofthe original packets, or the paths taken byacknowledgments, or both. Furthermore, the hiddennode problem requires a more careful analysis in thecase of asymmetric links.We conclude that MAC layer and routing protocolscapable of using asymmetric links are more complexthan traditional ones, but can improve theconnectivity, and provide bet
ter performance. We areconfident that approximate results for variousperformance metrics of wireless networks obtainedusing time-parallel simulation are sufficientlyaccurate and able to provide the necessary insightinto the inner workings of the protocols.
Guoqiang Wang received the B.S. degree from Southeast University,Nanjing, in 2001 and the Ph.D degree from University of CentralFlorida, Orlando, China, in 2007. His research areas include adhoc routing protocols, grid computing, and distributed andparallel simulation.
