| Wireless Sensor Networks can be used in Mission-Critical applications where the success of the mission depends on stringent QoS requirements. In this dissertation, two innovative cross-layer delivery protocols targeted for mission-critical networks are proposed. Multi-path Multi-SPEED (MMSPEED) protocol provides service differentiation and probabilistic QoS guarantees in two QoS domains. By allowing higher layers to select the most appropriate level of service, MMSPEED allocates network resources to packets and provide probabilistic guarantee to deliver packets within the applications's QoS requirements. The second protocol is called Sectored-Antenna MAC (SAMAC) protocol which is an integrated set of cross-layer communication protocols that exploits the potential benefits of sectored-antennas. In addition, we propose two analytical models for IEEE 802.11 DCF mechanism that accurately predict the performance of the DCF mechanism with a wide range of system parameters. Simplified versions of these models are used to optimize the performance of MMSPEED by selecting the optimal protocol parameters and to predict the E2E delay performance of SAMAC protocol. |
