Cognitive PHY and MAC layers for dynamic spectrum access and sharing of TV bands

摘要

Research in the physical (PHY) and medium access control (MAC) layers for dynamic spectrum access (DSA) and dynamic spectrum sharing (DSS) is still at its infancy. Aspects such as spectrum sensing, coexistence, measurement and spectrum management, network reliability and QoS support in face of the need to avoid causing harmful interference into incumbents, to name a few, are key to the success of future cognitive radio (CR) systems and have received little attention so far. In addition, it is critical to understand the interplay of these various cognitive radio concepts and how they impact the overall network performance. In this paper we address these questions by presenting the design and performance evaluation of a CR-based PHY and MAC for DSA and DSS of vacant television (TV) channels. This air interface described here forms the baseline of the current IEEE 802.22 draft standard, and features a number of key PHY and MAC CR-based components for use by license-exempt devices in the spectrum that is currently allocated primarily to TV services. Through simulations and prototyping, we analyze the performance of this first CR-based wireless network with respect to spectrum sensing, system capacity, QoS support, coexistence, and network reliability.