7. Frame Structure for Throughput Maximization in Cognitive Radio Communication

In this chapter, we propose a technique to eliminate the sensing-throughput trade-off of the conventional approach in order to increase the throughput of the cognitive radio user and simultaneously reduce interference with the primary users. We look at a cognitive user that employs a conventional frame, then perform spectrum sensing and transmission, finding that the cognitive user ceases data transmission at the beginning of each frame. Spectrum sensing is performed first for particular units of time, and data is then transmitted for the remaining frame duration. However, there is a potential problem in this scheme. It is well known from classical detection theory that an increase in sensing time results in a higher probability of detection and lower probability of false alarm; however, it also results in less data transmission time and hence limits the throughput of the cognitive radio user, causing a sensing-throughput trade-off problem. In addition, there is the problem of unpredictable primary user (PU) transmission during the transmission time of the cognitive user, resulting in data loss. In order to avoid the sensing-throughput trade-off and to maximize the throughput of spectrum sharing cognitive radio networks, we propose a technique that reduces the data loss rate by reducing collisions of frames of primary and secondary users. Finally, simulation results are provided and compared with the conventional approach. From these simulation results, it is demonstrated that the throughput is better for the proposed approach as compared to that of the conventional approach.