Qingchun Ren

Graduation Semester and Year




Document Type


Degree Name

Doctor of Philosophy in Electrical Engineering


Electrical Engineering

First Advisor

Qilian Liang


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 database 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 protocols 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 secure problem, we proposed a secure MAC protocol for WSNs. Our algorithm-FSMAC firstly design multiple indicators for intrusion detection according to the classification of popular DoS attacks on MAC layer of WSNs, and innovatively utilizes fuzzy logic theory to implement making decision on intrusion. In query processing, we proposed a quality-guaranteed and energy-efficient (QGEE) algorithm. QGEE utilizes in-network query processing method to task WSDSs through declarative queries, and confidence interval strategy to determine the accuracy of query answers. Given a query, the QGEE algorithm can reduce disturbance from measurements with extreme error and minimize energy consumption, while providing satisfying service for various applications. In MAC protocol design for ultra wideband, we proposed a throughput maximized MAC protocol (TM-MAC). In TM-MAC, we implement concurrent multiuser access scheme. For multiuser interference, we establish a model to adaptively adjust the data transmission rate to generate the expected signal to interference noise ratio (SINR) at the receiver side for reliable communications. In subset formation, we propose a general analytical framework that captures the unique characteristics of shared wireless channel and throughput variance.


Electrical and Computer Engineering | Engineering


Degree granted by The University of Texas at Arlington