Impact of cooperation on improving link reliability of cell edge users in cognitive radio networks

All mobile devices have a limited energy storage capacity which makes conservation and efficient utilization of energy quintessential. In the future Cellular Networks are expected to coexist with Cognitive Radios. The inclusion of Cognitive Radio(CR) technology in the IEEE 802.22 standard is a first step in this regard. This paper deals with improving the link reliability of a cell edge user in a cellular network where CR´s coexist with the mobile users of the cellular network. By improving the link reliability we avoid excessive utilization of energy through retransmissions. The Cell Edge User (Primary User with full spectrum rights) cooperates with a secondary user(user with no spectrum rights)when it is unable to establish a reliable link with the destination i.e. the direct link is severely faded. This paper introduces the concept of Degree of Cooperation which conveys the extent of cooperation required between a Primary User and a Secondary User to achieve successful transmission. By choosing an appropriate partner for cooperation both resource and energy efficient transmission is achieved.