J4 ›› 2012, Vol. 39 ›› Issue (1): 1-6.doi: 10.3969/j.issn.1001-2400.2012.01.001

• Original Articles •     Next Articles

Modeling and optimization of access opportunity in cognitive radio

HAN Weijia;LI Jiandong;YAO Junliang;LI Zan   

  1. (State Key Lab. of Integrated Service Networks, Xidian Univ., Xi'an  710071, China)
  • Received:2010-12-12 Online:2012-02-20 Published:2012-04-06
  • Contact: HAN Weijia E-mail:alfret@gmail.com

Abstract:

This paper proposes jointly optimizing the access opportunity and spectrum sensing to achieve the maximum efficiency of spectrum utilization for the secondary user. In cognitive radio, the opportunistic access interwinded with spectrum sensing plays a key role in determining the performance of the secondary system. However, current related research neglects the relationship between primary user and secondary user in the spatial domain, which leads to incorrect evalution of the quantity of avaliable access opportunity for the secondary user. To deal with this problem, a closed-form function is derived to calculate the secondary medium access probability with regard to the impact of spectrum sensing and user spatial distribution. By using this derived closed-form function, the secondary user can obtain the optimum sensing configuration to ensure the efficient spectrum utilization of the secondary system. Simulation results show the correctness of the closed-form function and the efficiency of the related optimization.

Key words: cognitive radio, spectrum sensing, access opportunity