| Multiple access protocols have great impact on wireless network performance. Especially in a cognitive radio (CR) environment where primary and secondary networks coexist within each other coverage area, the media access control (MAC) protocol design of secondary network really depends on the framework of primary network. Therefore, an effective MAC protocol design for both primary and secondary networks can improve the system performance, and avoid interference or just bring tolerable interference to primary network. In this dissertation, we investigate the MAC protocol design for both primary and secondary networks in CR environments. We first consider that the MAC protocol of primary network is slotted Aloha. And then, we use slotted Aloha/carrier sensing multiple access (CSMA) in secondary network (CR network) to make secondary users opportunistically access the vacant spectrum holes of primary network. Following, we consider that the MAC protocol of primary network is time division multiple access (TDMA) and the MAC protocol of secondary network is slotted Aloha/CSMA/packet reservation multiple access (PRMA). For the MAC protocols of both primary and secondary networks, we present the theoretical analysis of their average delay and throughput performance. All theoretical results are validated through simulations. Moreover, the new concept of MAC classification is introduced in this dissertation. A MAC classification scheme based on support vector machines (SVMs) is proposed for classifying an unknown MAC protocol as contention based or control based. |
