Medium access control in cooperative wireless networks with user mobility and incentive design
University of New Brunswick
In the past decade, cooperative wireless networks have emerged as a promising technology that allows wireless devices to take advantage of diversity and link adaptation. In this thesis, we focus on the design and analysis of the medium access control (MAC) layer for the cooperative wireless networks, aiming at two main issues in this field: relay selection under mobility and incentive-based allocation for relaying packets. Specifically, we proposed and analysed 1) an intelligent cooperative MAC protocol to select stable helpers to provide better throughput; 2) two coordination schemes for multiple helpers to tradeoff the diversity advantage and transmission delay; 3) a moneyless incentive scheme which can stimulate the agreement of cooperation; and 4) three monetary incentive allocation mechanisms to stimulate cooperative relaying while maintaining the desired properties. Firstly, our proposed cooperative MAC protocol, referred as PTCoopMAC, can make use of the out-of-date information from the overheard signals to select the optimal stable helper to improve the system throughput. Secondly, we analysed the unconditional relaying success probability for a wireless diversity system with multiple random moving helpers. One Aloha-based and one timer-based coordination schemes were designed to balance the success probability and transmission delay. Thirdly, the moneyless incentive scheme for one cooperative pair transmission can tune up and down the channel access probability of the helper and the source as the reward and payment, respectively. We further provided the conditions on how to select the tuning factors to reach the cooperation agreement. Finally, we proposed three monetary incentive allocation mechanisms towards different design goals. The Vickrey-Clarke-Groves (VCG)-based mechanism aims at efficiency in social welfare; the probabilistic entrance auction (PEA) mechanism targets at lowering the computational effort; and the randomized (RND) mechanism attempts to strike a balance between the two mechanisms. All the proposed solutions were extensively evaluated by simulations. The results demonstrated that our solutions successfully addressed the challenges posed by user mobility and incentive for the cooperative wireless networks. The quality of service (QoS) can be significantly improved by properly incorporating cooperation among user devices.