  This paper investigates the maximum stable throughput of a cooperative
cognitive radio system with energy harvesting Primary User and Secondary User.
Each PU and SU has a data queue for data storage and a battery for energy
storage. These batteries harvest energy from the environment and store it for
data transmission in next time slots. The SU is allowed to access the PU
channel only when the PU is idle. The SU cooperates with the PU for its data
transmission, getting mutual benefits for both users, such that, the PU
exploits the SU power to relay a fraction of its undelivered packets, and the
SU gets more opportunities to access idle time slots.
