Masoumeh Farmahini Farahani - Communication Technology Faculty Iran Telecommunication Research Center (ITRC) Tehran, Iran
Abdorasoul Ghasemi - Faculty of Electrical and Computer Engineering, K. N. Toosi University of Technology, Tehran, Iran
Seyyed Mohammad Razavizadeh - Department of Electrical Engineering, Iran University of Science and Technology (IUST) Tehran, Iran

In this paper, a new joint admission and power control scheme is introduced for wireless cognitive radio networks. It is assumed that the Cognitive Users (CUs) arrive sequentially in time and exploit the spectrum simultaneous to the licensed primary users. The objective is to minimize the blocking probability of the new arriving CUs while the interference limit constraint of primary users is not violated and the quality of service (QoS) requirements of the current admitted CUs is satisfied. To these aims, an algorithm is developed for CUs admission in which the power of the new arriving CU gradually increases according to two predefined parameters, Primary Interference Margin (PIM) and Secondary Interference Margin (SIM). In addition to protect the QoS of the current CUs, their powers are boosted by a particular parameter, which is calculated based on PIM and their maximum allowable power. Moreover, the PIM guarantees the protection of the primary users during the admission phase of the new arriving CU. Two admission control algorithms have been proposed, a safe admission which tightly admits a new CU and a moderate one which loosely accepts a new CU. Simulation results are provided to evaluate the performance of the proposed algorithms in terms of the blocking and outage probability and compared with recent proposed schemes. These results show that the proposed algorithms outperform the similar schemes while they are more suitable for a practical scenario.

Cognitive Radio Network, Underlay Transmission, Admission Control, Power Control