Partitioning-Based SOR for Minimum Energy Multicast Tree Problem in Wireless Ad Hoc Networks

In this paper we introduce the application of partitioning-based SOR (PSOR) algorithm to the minimum energy multicast tree problem in wireless ad hoc networks. PSOR was proposed for the minimum energy broadcast tree problem in our previous work and it can be applied to the multicast tree problem with small modification. PSOR for multicast maintains the same theoretical bound for the approximation ratio and computational running time as PSOR for broadcast. The computational results show improvement in the solution quality (in terms of the sum of the transmission powers). PSOR outperforms the other algorithms and it shows better results compared to ISOR (Iterated version of SOR) in terms of the ratio of solution quality improvement over running time increase. Recent careful study revealed that there was a bug in our implementation of SOR which caused worse performance than it should have. In this paper we used the results of the corrected version of SOR for the comparisons.