A Survey on Opportunistic Channel Scheduling in Cognitive Radio Networks with QoS Guarantees.

Abstract

An opportunistic scheduling policy is being employed in the cognitive radio networks wherein the applicable resources are allocated to the primary users and as well as secondary users by understanding their spectral activities and ranges. But major problem seen here is that secondary users have the capacity to transmit only if primary users are not transmitting. It is very much essential to provide the co-ordination between the primary and secondary users so that the channel is utilized efficiently. From the studies it is proved that a scheduling scheme is used that improve the services received by secondary users and at the same time aims to reduce the collisions with primary users. To effectively utilize the channel, a channel scheduling scheme is being used. Also to overcome delay tolerance(wherein maximum numbers of packet transmissions are done before exceeding the deadline).To keep track of this issue,dynamic priority queue scheduling mechanism is considered.Cognitive radio networks are basically used to improve the capacity of the network;researchers have also shown that these could be implemented from pure theory.