The authors investigate the performance of various diversity combining schemes in Internet of Things- Cognitive Radios (IOT-CR) system under the influence of co-channel interference limited environment. An approximate expression for probability density function (PDF) of maximum signal to interference ratio (SIR) at the receiver has been derived. By utilizing the derived PDF, closed loop expressions for Average post processing SIR, Ergodic capacity and Average bit error rate (ABER) have been derived. The proposed CR system is studied and analyzed under the impact of Peak transmit power (PTP) and Peak interference power (PIP) constraints. The achieved result shows that the Optimum combining (OC) at the receiver outperforms the traditional combining schemes in co-channel interference (CCI) scenario.