In cognitive radio networks the Primary User (PU) can select a Secondary User (SU) to act as a relay in order to assist his transmission. Both PU and SU must improve their utilities with this cooperation. A game is generated between PU and SU to maximize their benefits. This paper studies how the SU can serve the PU transmission in order to improve SU’s utility by harvesting PU’s radio signal to recharge SU’s battery. Moreover the paper studies the effect of the consumed scanning power on selecting the suitable PU. A matching algorithm is applied to help PUs and SUs in selecting each other for relaying and leasing processes.