GSAR: Greedy Stand-Alone Position-Based Routing protocol to avoid hole problem occurance in Mobile Ad Hoc Networks

The routing process in a Mobile Ad Hoc Network (MANET) poses critical challenges because of its features such as frequent topology changes and resource limitations. Hence, designing a reliable and dynamic routing protocol that satisfies MANET requirements is highly demanded. The Greedy Forwarding Strategy (GFS) has been the most used strategy in position-based routing protocols. The GFS algorithm was designed as a high-performance protocol that adopts hop count in soliciting shortest path. However, the GFS does not consider MANET needs and is therefore insufficient in computing reliable routes. Hence, this study aims to improve the existing GFS by transforming it into a dynamic stand-alone routing protocol that responds swiftly to MANET needs, and provides reliable routes among the communicating nodes. To achieve the aim, two mechanisms were proposed as extensions to the current GFS, namely the Dynamic Beaconing Updates Mechanism (DBUM) and the Dynamic and Reactive Reliability Estimation with Selective Metrics Mechanism (DRESM). The DBUM algorithm is mainly responsible for providing a node with up-to-date status information about its neighbours. The DRESM algorithm is responsible for making forwarding decisions based on multiple routing metrics. Both mechanisms were integrated into the conventional GFS to form Greedy Stand-Alone Routing (GSAR) protocol. Evaluations of GSAR were performed using network simulator Ns2 based upon a defined set of performance metrics, scenarios and topologies. The results demonstrate that GSAR eliminates recovery mode mechanism in GFS and consequently improve overall network performance. Under various mobility conditions, GSAR avoids hole problem by about 87% and 79% over Greedy Perimeter Stateless Routing and Position-based Opportunistic Routing Protocol respectively. Therefore, the GSAR protocol is a reasonable alternative to position-based unicast routing protocol in MANET

The Appropriate FEC Parity Amount to Guarantee High Quality for Video Streaming

Efficiency and capability of forward error correction (FEC) mechanism to recover from losses, is the main idea behind its utilization in Real-time applications like video streaming over Internet. The number of Internet users continue to increase every day, thus network traffic will increase. Such increasing in network traffic will cause network congestion to increase, increasing in network congestion make data loss obvious problem that affect streaming video presentation quality. The efficiency of FEC mechanism come from the reduction of the time needed to recover lost packets, and there is no need for an additional channel for retransmission. The goal of FEC is to add redundancy that can be used to recover from packet loss in multimedia application, this big task for FEC comes with main condition; to achieve acceptable and the desired quality of presentation, FEC has to be introduced with minimum overhead for real-time application. However, depending on the fact that packet loss is often unknown and time varying. So, the amount of extra data that will be sent with the original data in the FEC block is predetermined comparing to the loss, hence loss recovery rate depends on the amount of redundancy data. For this reason FEC may take three characteristics depending on the amount of redundant data, effective (if the redundant is sufficient to the lost data), ineffective (if the redundant is too little to the lost data), or inefficient (if the redundant is too much to the lost data). Our research will concentrate on this problem to propose a suitable solution, by matching the appropriate redundancy that can achieve effectiveness, through sending the proposed FEC parity amount aside with the original data of video application. Proposed results will guarantee minimum packet loss and packet loss ratio in streaming application for video. Furthermore, through this study we will verify the affect of variance amount of redundancy data on the loss recovery rate, to find the appropriate parity amount, which can be effective in the presence of data loss. During that, Simulation results will demonstrate our progress for this project step by step to insure the works. Through extensive simulation, we will evaluate the scalability of the chosen redundancy data amount to improve aggregate FEC performance through video transmission