Routing protocols enhancement for delay tolerant networks

Routing in Delay/Disruption Tolerant Networks (DTN) is active area of research and acquires the attention of researchers as being the most adequate solution for the problem of intermittently connection in Mobile Ad hoc Networks (MANET). The challenge is to find a routing algorithm that can deal with dynamic environment causing networks to split and merge, considering nodes mobility.;In this dissertation we enhance the performance of DTN routing protocols in Delay Tolerant Mobile Ad Hoc Networks by accomplishing the following goals to address the routing challenges: (1) Design a new probabilistic routing protocol based on history of encountered nodes. (2) Determination of strength and weakness of DTN routing protocols by comparison. (3) Enhancing DTN routing protocols by inclusion of study of the impact of link availability on performance of the DTN-based protocols (4) A Cross Layer Design (CLD) to enhance service quality of some common MANET-based routing protocols.;We have designed a DTN-based probabilistic routing algorithm using the concept of History of Encounters, HEPRA. Our routing protocol relies on the knowledge of the mobility of nodes and uses the history of encountered nodes to predict its future suitability to deliver messages to next node toward destination. The probabilistic routing approach is built on a store-carry-forward network to deliver messages to final destination in MANET environment. We evaluate the performance of HEPRA in various network environment behaviors.;We present an evaluation and analysis of performances of some common DTN routing protocols including HEPRA in terms of different parameters in MANET environment. We illustrate the behaviors of the DTN routing protocols in terms of various parameters and variables. This evaluation presents the strengths and weakness of selected protocols.;We study the impact of link availability as a parameter of the physical layer environment on the performance of DTN routing protocols. This study is the first research analysis of the impact of physical layer parameters on the performance of DTN routing protocols. We demonstrate through the simulation how those protocols act against changes in network environment.;We propose a CLD to attain a reliable data transmission in MANET. We present a model that allows the network layer to adjust its routing protocol dynamically based on Signal Noise Ratio (SNR) and Received Power (RP) along the end-to-end routing path for each transmission link to improve the end-to-end routing performance in MANET environment.;In this dissertation, we present the design basis for those contributions, illustrate and evaluate our design efforts, and discuss the advantages of our models.