The Study And Improvement Of Efficient Team Multicast Protocols In Wireless Networks

Mobile ad hoc network (MANET) is a self-organizing and multi-hop wireless network without any existing infrastructure. Due to the distinct features it possesses, MANET has a variety of applications in almost all fields of study such as collaborative computing and crisis management (like in disaster recovery). Nodes in a MANET are free to move, communicate to each other directly or via a multi-hop route. So routing protocol is an indispensable part in Ad Hoc networks. The main goal of the design of routing protocol in Ad Hoc networks is: While satisfying the specific need of application, try to decrease the cost of the whole network. This will make the whole resource of the network more efficiently used, and increase the throughput of the network.In this paper, we mainly study the following three representative multicast protocols: ODMRP, M-LANMAR and Ripple which is put forward by our paper, under the scenarios using directional antennas with team mobility. We put an emphasis on the discussion of key technology problems, main work mechanism and the merits of the three multicast protocols.Ripple is a novel team multicast routing protocol presented in this paper, which is an improvement of Multicast-enabled Landmark Ad Hoc Routing (M-LANMAR), for mobile ad hoc networks using directional antennas. It is designed specially for the scenarios using directional antennas with team mobility to satisfy the need to propagate messages to all the members within a group. One of the limitations of M-LANMAR lies in its employing flooding to deliver messages in a group. Concerned with the directional antennas which offer tremendous potential for improving the performance of ad hoc networks, flooding will bring about considerable increase of the number of transmission and extra messages transmitted, which will cause a notable decline in the energy level nodes hold and the function of the whole network. For the reasons above, we propose a mechanism with diffusing the messages circle by circle to finally cover the whole members of the group.At last, through the mathematical deductions under a grid model and simulative implementation on the network simulator developed by our own, we compare and analyze the performance of ODMRP, M-LANMAR and Ripple deeply under the scenarios we study.The main contributions of this paper are listed as below: discussing the relative characteristics of Ad Hoc networks and the classification of routing protocols in Ad Hoc networks; mainly studying two representative multicast protocols: flat on-demand routing protocol ODMRP and hierarchical table-driven routing protocol M-LANMAR; to the limitation of M-LANMAR, proposing a new team multicast protocol, named "Ripple", for ad hoc networking with directional antennas; extending the message structure of M-LANMAR protocol; describing the operation of our protocol in detail; evaluating the performance of all the above three protocols by theoretical model deduction and simulative implementation respectively.