| Recent devices developed for emerging wireless networks, such as 4G cellular networks, wireless mesh networks, and mobile ad hoc networks, support multiple communication substrates and require execution of multiple protocols within a layer, which cannot be supported efficiently by traditional layered protocol stack approaches. Our goal in this thesis is to discover the minimal set of requirements for simultaneously supporting the use of multiple protocols in the same stack layer without requiring modifications of the protocols and retaining that the modularity of the stack architecture so that future protocols can easily be incorporated.;To achieve this goal, we propose Universal Protocol Stack (UPS), which provides support for the execution of multiple protocols within a layer simultaneously in a modular way through packet-switching, information-sharing, and memory management. The implementation and simulations of UPS show that the overhead incurred to implement UPS is very low, and little or no modifications are required to adapt existing protocols to the UPS framework, yet there is benefit to the application in terms of reduced traffic or reduced delay/energy. As an example, we develop an approach to support multiple radio interfaces by abstracting all the available interfaces using a single virtual interface within the UPS framework. The selection of the specific physical interface to use per packet is done by the virtual interface, thus ensuring that no modifications of the upper layer protocols are required. This provides the opportunity for algorithms at the virtual interface to optimize the selection of the physical interface to improve the network performance. Results from simulations show that the use of a virtual interface is feasible and can improve the network performance.;While new protocol stack architectures are important to support multiple protocols and communication interfaces, efficient protocols are equally important to support emerging networks. We propose a stateless receiver-based multicast protocol, called RBMulticast (Receiver-Based Multicast), which removes the need for costly multicast tree and neighbor table maintenance, yet provides high success rates and low delay. This makes RBMulticast an excellent choice for multicasting in dynamic networks, where state maintenance is costly. Additionally, using the idea of receiver-based routing for convergecast transmissions, we find the duty cycle of a node as a function of its distance to the sink to minimize the expected energy dissipation. |
