This paper proposes an outage analysis framework for cooperative cognitive networks with proactive relay selection and selection combining (SC) under licensed outage constraint, maximum transmit power constraint, independent non-identical () fading distributions, erroneous channel information, and licensed users’ interference. | TAÏP CHÍ PHAÙT TRIEÅN KH&CN, TAÄP 18, SOÁ K6- 2015 On the performance of cooperative cognitive networks with selection combining and proactive relay selection Ho Van Khuong Vo Que Son Luu Thanh Tra Ho Chi Minh city University of Technology, VNU-HCM, Vietnam Pham Hong Lien University of Technical Education, Ho Chi Minh city, Vietnam (Manuscript Received on July 15, 2015, Manuscript Revised August 30, 2015) ABSTRACT: This paper proposes an outage analysis framework for cooperative cognitive networks with proactive relay selection and selection combining (SC) under licensed outage constraint, maximum transmit power constraint, independent non-identical () fading distributions, erroneous channel information, and licensed users’ interference. Towards this end, we firstly suggest power allocation for unlicensed transmitters to satisfy power constraints and account for erroneous channel information and licensed users’ interference. Then, we propose an exact closed-form outage probability formula for the unlicensed network to promptly evaluate system performance and provide useful insights into performance limits. Multiple results show performance trade-off between the unlicensed network and the licensed network, error floor in the unlicensed network, considerable system performance degradation owing to erroneous channel information and licensed users’ interference, and significant performance enhancement due to the increase in the number of relays. Keywords: Proactive relay selection, erroneous channel information, cognitive radio. 1. INTRODUCTION Currently, many emerging wireless services such as high definition video streaming, video calling, file transferring and high-speed internet access demand more and more radio spectrum while the conventional allocation of frequency bands by means of fixed licensed users (LUs) is not efficient, causing spectrum shortage. This shortage conflicts with a severe spectrum underutilization as reported in an .
