Bandwidth-efficient multicast in heterogeneous wireless networks

In this paper, we propose a bandwidth-efficient multicast mechanism for heterogeneous wireless networks. We reduce the bandwidth cost of a shortest-path IP multicast tree by adaptively selecting the cell and the wireless technology for each mobile host to join the multicast group. Our mechanism enables more mobile hosts to cluster together and lead to the use of fewer cells to save the scarce wireless bandwidth. Besides, the paths in the multicast tree connecting to the selected cells share more common links to save the wireline bandwidth. We formulate the selection of the cell and the wireless technology for each mobile host in the heterogeneous wireless networks as an optimization problem. We use integer linear programming to model the problem and design an distributed algorithm based on Lagrangean relaxation. Our mechanism supports the dynamic group membership and offers mobility of group members. Moreover, our mechanism requires no modification on the current IP multicast routing protocols.