1. Analysis of Cognitive Radio Spectrum Access Student Name: Yeung Wing Yu Supervisor: Dr. Wong, Eric W M Assessor: Prof. Zukerman, Moshe

2. Contents Objectives of Final Year Project Background about CR Mathematical model Simulation Numerical Results & Discussions Conclusion

3. Objectives of FYP Analyze cognitive system performance Simulation programs & mathematical analysis Effects on providing extra buffers

4. Allocation of Radio Spectrum Source: Cognitive Radio and Dynamic Spectrum Access [4]

6. CR (Cognitive Radio)

7. Licensed & unlicensed

8. PriorityHigher priority Lower priority Primary User Cognitive User

9. Operations for Cog. Radio System We are Cognitive (unlicensed) Users!! We are Primary (licensed) Users!! ．．． ．．． Group A: Cognitive Users ．．． A1 AN ANK AN(K-1)+1 B1 BK Group B: Primitive Users ．．． Frequency

10. A parking lot with stalls

12. M/M/n/n model

13. M/M/n/n+Q model

14. M/M/n/n/S model

15. M/M/n/n+Q/S modelBasic Model Advanced Model Av. Interarrival Rate No. of Servers Population Av. Service Rate Extra Buffers

17. Primary:

18. n Servers, finite Buffers, finite population

19. M/M/n/n+Q/S model

20. Cognitive:

21. n x N Servers, finite Buffers, finite population

23. Buffers – Bi

24. Population – Ml

25. Cognitive Users seem as transparent

26. M/M/n/n+Q/S model

27. Av. Interarrival rate – 1/λl

28. Av. Holding time – 1/μlPrimary Users

29. Normalization State Probabilities: Blocking Probability:

31. Buffers – Bj

32. Population – Mc

33. M/M/nN/nN+Q/S model

34. Av. Interarrival rate – 1/λc

35. Av. Holding time – 1/μcCognitive Users Cognitive Users Primary Users i, j

36. Queuing Model 0,0 0,1 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 0,0 1,1 1,2 1,3 1,4 1,5 1,6 1,7 2,5 2,0 0,0 2,1 2,2 2,3 2,4 3 buffers for cognitive users 3,0 0,0 3,1 3,2 3,3 Orange: Cognitive queuing only Purple: Both users queuing Population (Primary) = 6 (with 2 buffers) Population (cognitive) = 10 (with 3 buffers) No. of Servers = 3 One primary band can be used by 2 cognitive users, or N = 2 4,0 0,0 4,1 4,2 4,3 5,0 0,0 5,1 5,2 5,3

37. Queuing Model iN + j < nN 0,0 0,1 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 0,0 1,1 1,2 1,3 1,4 1,5 1,6 1,7 2,5 2,0 0,0 2,1 2,2 2,3 2,4 3 buffers for cognitive users 3,0 0,0 3,1 3,2 3,3 Orange: Cognitive queuing only Purple: Both users queuing Population (Primary) = 6 (with 2 buffers) Population (cognitive) = 10 (with 3 buffers) No. of Servers = 3 One primary band can be used by 2 cognitive users, or N = 2 4,0 0,0 4,1 4,2 4,3 5,0 0,0 5,1 5,2 5,3

38. Queuing Model iN + j ≥ nN and i < n and j ≤ (n-i)N + Bj and (i+1)N + j ≤ nN + Bj 0,0 0,1 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 0,0 1,1 1,2 1,3 1,4 1,5 1,6 1,7 2,5 2,0 0,0 2,1 2,2 2,3 2,4 3 buffers for cognitive users 3,0 0,0 3,1 3,2 3,3 Orange: Cognitive queuing only Purple: Both users queuing Population (Primary) = 6 (with 2 buffers) Population (cognitive) = 10 (with 3 buffers) No. of Servers = 3 One primary band can be used by 2 cognitive users, or N = 2 4,0 0,0 4,1 4,2 4,3 5,0 0,0 5,1 5,2 5,3

39. Queuing Model iN + j ≥ nN and i < n and j ≤ (n-i)N + Bj and (i+1)N + j > nN + Bj 0,0 0,1 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 0,0 1,1 1,2 1,3 1,4 1,5 1,6 1,7 2,5 2,0 0,0 2,1 2,2 2,3 2,4 3 buffers for cognitive users 3,0 0,0 3,1 3,2 3,3 Orange: Cognitive queuing only Purple: Both users queuing Population (Primary) = 6 (with 2 buffers) Population (cognitive) = 10 (with 3 buffers) No. of Servers = 3 One primary band can be used by 2 cognitive users, or N = 2 4,0 0,0 4,1 4,2 4,3 5,0 0,0 5,1 5,2 5,3

40. Queuing Model i ≥ n and j ≤ Bj 0,0 0,1 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 0,0 1,1 1,2 1,3 1,4 1,5 1,6 1,7 2,5 2,0 0,0 2,1 2,2 2,3 2,4 3 buffers for cognitive users 3,0 0,0 3,1 3,2 3,3 Orange: Cognitive queuing only Purple: Both users queuing Population (Primary) = 6 (with 2 buffers) Population (cognitive) = 10 (with 3 buffers) No. of Servers = 3 One primary band can be used by 2 cognitive users, or N = 2 4,0 0,0 4,1 4,2 4,3 5,0 0,0 5,1 5,2 5,3

47. Numerical Results & Discussions Ml = 20 , Mc = 20 and n = 5, N = 4, UTP = 0.5

51. Numerical Results & Discussions Ml = 20 , Mc = 20 and n = 5, UTP = 0.5, Bi= 4 N=2 N=3 N=4 N=5

52. Numerical Results & Discussions

53. Numerical Results & Discussions

55. Small portions of extra buffers reduce blocking & enhance throughput for both users

56. Standardisation for Cog. Radio System in progress

57. Violation – Unlicensed users MUST follow the rules

59. Thank You!