| We consider protocol design and performance analysis in mobile ad hoc networks (MANETs) in a cross layer point of view. We investigate the behaviors of network layer, multiple access control (MAC) layer, and physical layer, and reveal the interactions among them. In addition, we also investigate the impact of mobility on network performance.;The objective of the thesis is as followings: demonstrate the importance of lower layer behaviors in the behaviors and performance of upper layers; eliminate the negative impact of mobility on protocol performance; set up performance analysis framework for upper layer protocols by incorporating lower layer behaviors and performance; and propose high performance protocols by exploiting lower layer behaviors.;First, at the network level, for efficient broadcast protocols we look at the low coverage problem caused by packet reception with probability under realistic physical layers. A redundant radius mechanism is provided to be incorporated into energy efficient broadcast protocols to guarantee network coverage while keep energy efficiency.;Secondly, we look at the effect of dynamic topology caused by mobility on the performance of network protocols. Proactive neighborhood tracking scheme is proposed to predict neighbors' actual positions when forwarding occurs.;Thirdly, we provide two cross-layer mathematical frameworks for the evaluation of routing protocols and MAC protocols, respectively. We model the proactive or reactive routing protocol with a combinatorial model, where the routing logic is synthesized along with the characterization of MAC performance. We also present a framework to incorporate the PHY effect and behaviors into the analysis and modelling of MAC protocols, which demonstrates the PHY behavior importance on MAC protocol design, and provides a way to analyze MAC protocol performance accurately.;After that, we aim to take advantages of PHY layer effect and behaviors in the design of high performance MAC protocols. We follow two directions: employ advanced PHY communication techniques or play with traditional PHY behavior effect. We first try to exploit the advanced one-to-multiple (Multi-packet Transmission: MPT) or multiple-to-one (Multi-packet Reception: MPR) PHY communication paradigm, and propose an adaptive MPT or MPR MAC protocol to let multiple transmissions occur concurrently corresponding to traffic conditions. However, currently this kind of advanced PHY communication needs expensive hard devices and is not popularized yet. Therefore, we employ the common peer-to-peer communication style, while aim to improve throughput by selecting appropriate receivers. It exploits PHY capture effect and is based on instant channel conditions achieved by probing to multiple possible receivers. |
