Performance and fairness study of overlay spectrum sharing in a cognitive radio environment | |
| Author | Kayastha, Nipendra |
| Call Number | AIT Thesis no.ICT-08-15 |
| Subject(s) | Markov spectrum Radio frequency allocation Cognitive radio networks |
| Note | A thesis submitted in partial fulfillment of there quirements for the degree of Master of Engineering in Information and Communication Technologies, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. ICT-08-15 |
| Abstract | Cognitive radio users are the opportunistic users which try to use the available idle licensed spectrum without interfering with the licensed users. The cognitive users are forced to terminate whenever the licensed users reappear and demand for the spectrum which is being used by them. In this thesis work, performance of cognItIve radio is studied for three types of environment which are classified as small (1 ≤ n < 5), medium (5 ≤ n ≤ 20) and large systems (n > 20). Uncontrolled, controlled and cognitive spectrum hopping overlay access schemes are studied through analytical and simulation method. For analytical solutions, two dimensional Markov model with Poisson arrival rate and exponential service time with finite server is considered. For simulation, a generic simulation model is developed which is capable of handling mentioned overlay spectrum sharing techniques with provision to handle constant, uniform and Pareto service time distribution and supports primary and cognitive users with one or two bandwidth units. The simulation results show that cognitive users with cognitive spectrum hopping access scheme have better performance than the uncontrolled access scheme. For small systems, the cognitive hopping has measurable effect in reducing the forced termination probability of the cognitive users without much improving their bandwidth utilization. It is observed that the forced termination decreases with increasing primary to cognitive holding time ratio without having any measurable effect on the utilization of the cognitive users. Cognitive buffering on the other hand has significant effect on improving the performance of the cognitive users for small systems than the large systems. Higher bandwidth utilization can be achieved by using the cognitive spectrum hopping access scheme for large systems whereas for small system cognitive users can be allowed to wait in the buffer whenever they are forced terminated or blocked by the system |
| Year | 2009 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. ICT-08-15 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Information and Communications Technologies (DICT) |
| Academic Program/FoS | Information and Communication Technology (ICT) |
| Chairperson(s) | Erke, Tapio J.; |
| Examination Committee(s) | Rajatheva, R. M. A. P.;Teerawat Issariyakul; |
| Scholarship Donor(s) | Government of Finland; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2009 |