| For the purpose of improving road safety and reducing billions of dollars property loss every year due to traffic accidents, research communities are working on the development of vehicular ad hoc networks (VANETs) as an important component to realize active auto protection. Besides the emergency warning application, VANETs have potentials to provide other kinds of applications such as road information inquiry, Internet connection, multimedia application, and so on.In VANETs, medium access control (MAC) protocols at the MAC layer and routing protocols at the network layer are two of the most important issues. For medium access control, this thesis proposed a new protocol, called reliable busy tone multiple access protocol with neighboring information table (RBTMA-NIT), to support emergency warning transmission with the consideration of the priority of copies, distance and neighboring information table (NIT). It has been shown that the RBTMA-NIT can greatly shorten the covering time of emergency message. Meanwhile, another MAC protocol, called multiple channels busy tone multiple access with snooping (S-MBTMA), has been proposed by us to provide high throughput transmission in the multi-channel VANETs environment. By simulation, the S-MBTMA demonstrated its improvement on the system utilization. For routing, this thesis discussed the challenging factors in the routing design, reviewed and analyzed the proposed routing protocols in terms of cost and disadvantage, and proposed guidelines for routing design in VANETs. |
