Supporting real-time traffic in cognitive radio networks

While designing the cognitive radio networks, enough care would be taken to safeguard the transmissions of primary users so that their quality of service (QoS) is not affected by the transmissions of secondary users. Opportunistic access of the spectrum is permitted to secondary users, through which the vacant channels of the spectrum are used by secondary users on temporary basis. In this mode, when the primary user of that channel returns back for transmission/ reception, the secondary user has to vacate that channel. If that secondary user is engaged in transmitting delay-sensitive (real-time) data, it will lead to severe degradation of its QoS due to this channel quitting requirement. In such instances, if another vacant channel of the spectrum can readily be offered to this secondary user, the device will be able to satisfy its real-time transmission requirements. For this to happen, appropriate categorization of secondary user traffic based on their real-time needs, and planning the usage of vacant channels based on the importance of data from various secondary users are needed. These mechanisms are proposed in this work Simulation studies of the proposed mechanisms show that the blocking probabilities of real-time data secondary devices are much lesser compared to other devices.