Cooperative Spectrum Sensing And Allocation In Cognitive Radio Networks

Recent year has seen a significant amount of research in cognitive radio networks (CRNs) for alleviating spectrum scarcity and increasing spectrum usage. The underlay paradigm is extensively investigated in the literatures, where secondary users (SUs) should sense a spectrum hole before it accesses a licensed channel. The fundamental design in underlay CRNs is to protect the primary users (PUs) and to increase the utilities of licensed channel and SUs, which are the key functions of spectrum sensing and dynamic sharing. However, the space-time varying property in spectrum availability and channel fading bring significant challenges in spectrum sensing and dynamic spectrum sharing. To tackle these issues, an emerging trend is to develop various space-time diversities, e.g. cooperative spectrum sensing and collaborative spectrum sharing. In this paper, we study the issues of cooperative spectrum sensing and resource allocation in cognitive radio networks. Our work can be divided into three parts:First, we consider the cooperative spectrum access in cellular network. In this paper, we propose a cross-layer based inter-cell cooperative spectrum access approach. The proposed approach highly explores the space diversity of secondary users'distribution and the preference diversity of secondary users on channel accessing, which allows secondary users from different cells sharing the sensing results of channels used within their cells with each other and further accessing a better channel with the help of corresponding secondary users. Based on utility functions of secondary users within different cooperative groups, we further apply coalition game to solve the formation problem of cooperative groups. Numeric simulations verify that our proposed cross-layer cooperative framework can increase quality of service of both primary users and secondary users.Second, we jointly consider the issues of spectrum sensing and spectrum allocation. A Flexibly Cooperative Spectrum Sensing and Allocation (FCSSA) framework in cognitive radio networks is developed. The proposed FCSSA framework captures the essential interactive function between cooperative spectrum sensing and allocation, which allows licensed channel and secondary users bargaining on their decisions, such as the enforceable requirements of spectrum sensing time, energy detection threshold and secondary users'payment for spectrum access, to maximize their utilities respectively. Moreover, we apply Stackelberg game to formulate the joint cooperative spectrum sensing and allocation design. The leaders (primary users) decide spectrum sensing time and energy detection threshold according to the predictable behavior of secondary users. The followers (secondary users) make their payment decision underlying a non-cooperative game according to limited information form licensed channel. Numeric simulations verify that our proposed jointly design framework in cooperative spectrum sensing and allocation can increase the agility and effectiveness of dynamic spectrum usage.In the end, the design of protocols of cooperative cognitive radio network is given through the analysis of information interchanged among components of network, issues of formation and user selection of cooperative group and the allocation of spectrum sensing and access. Based on above research, one structure of the system is illustrated with detailed explanation.