Call Admission Control with Spectrum Leasing in Cognitive Radio Networks

Shun-Ping Chung ； Yen-Ting Wu ； Ssu-Ying Peng

《TANET2017 臺灣網際網路研討會》 2017年 (2017/10) Pp. 903-907

https://doi.org/10.6728/TANET.201710.0157

摘要

With the increasing requirement for wireless communications, the demands for bandwidth and data transmission rate are growing. On the other hand, the available spectrum is not only scarce but also underutilized. To improve the utilization of radio spectrum, the concept of Cognitive Radio (CR) is proposed. Cognitive radio allows secondary users (SUs) to opportunistically access a spectrum hole which is in the same frequency bands as primary users (PUs). Traditionally, PUs have the preemptive priority over SUs, and hence the acquisition of underutilized channels by SUs is not guaranteed. Two call admission control (CAC) schemes are developed: CAC1 and CAC2. With CAC1, the bandwidth requirement of each SU is one channel that with CAC2 is a constant bandwidth which is greater than one. In addition, spectrum leasing for SUs are enforced, where the licensed spectrum band is divided into two parts, i.e., the leased spectrum and unleased spectrum, and for all CAC schemes PUs only have the preemptive priority over SUs in the unleased spectrum. Furthermore, to mitigate the dropping probability of preempted SUs, a buffer is utilized to accommodate the preempted SUs till their maximum waiting time expires. The simulation models are developed for two considered CAC schemes with or with buffer. The performance measures of interest include the blocking probability and throughput for PUs and SUs, and the dropping probability for SUs. Furthermore, we compare the performance of the system with buffer and that without buffer. We also compare the performance of CAC1 and CAC2. Last but not least, computer simulation is written in Visual Studio 2013.

關鍵字

Cognitive radio network ； call admission control ； spectrum leasing ； buffer ； SU dropping probability ； throughput