In this dissertation, there are four main aspects included: energy reservation on

MAC layer, secure improvement for DoS attacks on MAC layer, query processing with

uncertainty for sensor systems, and throughput maximization on MAC layer

for ultra wideband communication systems.

In energy reservation, we proposed asynchronous MAC (A-MAC) protocol and

asynchronous schedule-based MAC (ASMAC) protocol. A-MAC and ASMAC proto-

cols are attractive due to their suitabilities for multihop networks and capabilities of

removing accumulative clock-drifts without any network synchronization. Moreover, we

build a traffic-strength- and network-density-based model to adjust essential algorithm

parameters adaptively-In this dissertation, there are four main aspects included: energy reservation on

MAC layer, secure improvement for DoS attacks on MAC layer, query processing with

uncertainty for sensor　systems, and throughput maximization on MAC layer

for ultra wideband communication systems.

In energy reservation, we proposed asynchronous MAC (A-MAC) protocol and

asynchronous schedule-based MAC (ASMAC) protocol. A-MAC and ASMAC proto-

cols are attractive due to their suitabilities for multihop networks and capabilities of

removing accumulative clock-drifts without any network synchronization. Moreover, we

build a traffic-strength- and network-density-based model to adjust essential algorithm

parameters adaptively