Performance Evaluation of Ad Hoc Routing Protocols to Deliver MPEG-4 Traffic Kunagorn Kunavut Department of Telecommunications Science Faculty of Science and Technology Assumption University, Thailand Email: kunagorn@scitech.au.edu Teerapat Sanguankotchakorn Telecommunications Field of Study School of Engineering and Technology Asian Institute of Technology, Thailand Email: teerapat@ait.ac.th Abstract—Mobile ad hoc network is an infrastructureless wireless network with limited bandwidth and highly dynamic topology. It can support wide variety of applications by using specialized routing protocol either proactive or reactive protocols. However, to support multimedia applications to deliver voice and video data over ad hoc network is very challenging due to its characteristic mentioned above. MPEG-4 encoding scheme seems to be suitable for ad hoc networks since they offer high video quality with higher compression ratio than other MPEG stan- dards. Because of this motivation, performance investigation on MPEG-4 traffic delivery over ad hoc network is required. Hence, we construct the simulation to demonstrate the performances of various ad hoc routing protocols including both proactive and reactive protocols when they deliver MPEG-4 bitstreams. I. I NTRODUCTION Mobile Ad hoc Network so called MANET is an in- frastructureless wireless network. All nodes in this type of network are responsible for finding paths and forwarding data to destination nodes without using any existing infrastructures. Hence, each node in ad hoc network requires specific routing protocol to perform such functions. These protocols can be classified into two main types which are proactive and reactive routing protocols. In proactive or table-driven routing protocols, nodes create topology database by collecting the routing updates which sent by the others every predefined interval. These routing information are used in path finding algorithm to find the best paths to destinations. Thus, there is no delay occurring for obtaining the paths since they always exist in routing table. However, more control overheads are flooded to the networks due to periodically routing updates. Examples of these routing protocols are DSDV [1], OLSR [2] and TBRPF [3]. In contrast to proactive protocols, nodes implementing reac- tive or on-demand routing protocols will initiate the route dis- covery process only when they have data packets to transmit. Hence, they can begin transferring the data once they receive the Route Reply packets from destination nodes. Thus, routing information will be sent only when required by source nodes. AODV [4] and DSR [5] are the examples of routing protocols falling into this category. Many research works [6], [7], [8], [9] were proposed to compare the performances of reactive and proactive routing protocols using Constant Bit Rate (CBR) traffic. However, none of them consider Variable Bit Rate (VBR) as traffic to be delivered over ad hoc networks. Most of real-time applications e.g., video broadcasting, video on demand, video conferencing and etc. are encoded using VBR scheme and they are bandwidth and delay constrained applications. Thus, it is very interesting to investigate the capability of ad hoc network which is limited bandwidth and highly dynamic topology network to provide services for VBR traffic. Hence, we study the performances of ad hoc network when it delivers MPEG-4 bitstreams. MPEG-4 is targeted to provide high video quality by using coding technique with additional functionality to achieve higher compression ratio than MPEG- 1 and MPEG-2. Thus, its encoded bitstream is suitable for the end-user devices that cannot access to the high speed networks. II. AD HOC ROUTING PROTOCOLS Ad hoc routing protocols can be classified into two main paradigms which are proactive and reactive routing protocols depended on the way they acquire routes or paths to desti- nations as explained in section I. In this research work, we measure the performances of OLSR, DSR and AODV since they have been submitted to IETF MANET Working Group to be standardization. The details of them are explained below. A. Optimized Link State Routing Protocol (OLSR) OLSR composes of four main modules which are neighbor sensing, message flooding, topology information and route calculation. Each node can sense the other nodes up to 2- hop neighbors by collecting Hello messages which contain the emitting node’s own address and the list of neighbors known to this node. OLSR implements Multipoint Relaying (MPR) technique [10] as the flooding algorithm. According to this technique, only nodes selected as MPRs are allowed to forward Topo- logy Control (TC) messages to optimize number of control overhead flooded to the network. Each node collects TC messages which contain the address of the node generating the TC message, as well as the address of its MPR selector to build topology information which will be applied in a shortest path algorithm to compute the shortest routes (lowest hop counts paths) from a node to any reachable destinations in the network. ___________________________________ 978-1-4244-6870-6/10/$26.00 ©2010 IEEE 207