1. Analysis of Active Interference Cancellation for Cognitive Radio MB-OFDM UWB Speaker: 王貞傑 Professor: 吳仁銘教授 date: 2007. 06. 01

2. Outline Introduction to cognitive radio in ultra wideband AIC algorithm Simulation Conclusion

3. Introduction to cognitive radio

4. Spectrum utilization

5. Resource :spectrum UWB : 3.1-10.6 GHz Wimax : 3.3-3.8 GHz,5.4-5.825 GHz IEEE802.11a : 4.9 -5.85 GHz

6. Employ multi-band orthogonal frequency division multiplexing (MB-OFDM)

7. Cognitive Radio object 1) highly reliable communication 2) efficient utilization of the radio spectrum “Cognitive Radio” does what? 1) sense the spectral environment over a wide available band 2) use the spectrum only if communication does not interfere with licensed user. multiple signal dimensions : time, frequency, physical space, and user networks

8. “Cognitive Radio” Task 1) Radio-scene analysis 2) Channel-state estimation and predictive modeling 3) Transmit-power control and dynamic spectrum management => feedback

9. Interference avoidance method Non-rectangular windows Active interference canceling (AIC)

10. AIC algorithm

11. turning off the interfering tones: the inter-carrier interference may limit the notch depth to 5-10 dB AIC (active interference cancellation tones)

12. Over-sampling Why over-sampling MB-OFDM based interference Over-sampling rate = r

15. Minimization

16. MIMO AIC

18. Minimization

24.  唯一解 : 利用錯開頻帶，來消除所要干擾主要頻帶 的訊號，頻帶間不重複利用，否則 det =0  頻帶間有重複 (overlap) ，則造成有無限多組解

25. Simulation

26. Picture parameter Axis explanation & Input Parameter re-sampling rate Vs AIC number Turn-off Vs AIC with different re-sampling rate Comparison in different re-sampling rate Different protected sub-carriers MIMO AIC

27. Axis explanation: X-axis : sub-carrier index ( over-sampling ) Y-axis: power spectrum Input : QPSK ( a + j*b ) Random Number of fft =128

28. Parameter: over-sampling rate ( r ) protect-band sub-carriers AIC number

29. Picture parameter Axis explanation & Input Parameter re-sampling rate Vs AIC number Turn-off Vs AIC with different re-sampling rate Comparison in different re-sampling rate Different protected sub-carriers MIMO AIC

30. Protected spectrum 3 sub-carriers R=2 Turn-off

32. Protected spectrum 3 sub-carriers R=2 AIC

34.  With using 5 tones of AIC, It reaches the best performance.  more than 5 tones, e.g. 7 tones, performance goes back.

35. Protected spectrum 3 sub-carriers R=3 Turn-off

37. Protected spectrum 3 sub-carriers R=3 AIC

39.  With using 7 tones of AIC, It reaches the best performance.  more than 7 tones, e.g. 9 tones, performance goes back.

40. Protected spectrum 3 sub-carriers R=4 AIC

42.  With using 9 tones of AIC, It reaches the best performance.  more than 9 tones, e.g. 11 tones, performance goes back.

43. Protected spectrum 3 sub-carriers AIC R=5 best in 9 tones Protected spectrum 3 sub-carriers AIC R=6 best in 9 tones

44. Protected spectrum 3 sub-carriers AIC R=7 best in 9 tones Protected spectrum 3 sub-carriers AIC R=8 best in 11 tones

45. Protected spectrum 3 sub-carriers AIC R=100 best in 11 tones Protected spectrum 3 sub-carriers AIC R=50 best in 11 tones

46. #AIC357911 r12348

47. Picture parameter Axis explanation & Input Parameter re-sampling rate Vs AIC number Turn-off Vs AIC with different re-sampling rate Comparison in different re-sampling rate Different protected sub-carriers MIMO AIC

48. Comparison in different re-sampling rate(1/4) R=2 R=3

49. Comparison in different re-sampling rate(2/4) R= 4 R=5

50. Comparison in different re-sampling rate(3/4) R=6 R=7

51. Comparison in different re-sampling rate(4/4) R=8

52. Picture parameter Axis explanation & Input Parameter re-sampling rate Vs AIC number Turn-off Vs AIC with different re-sampling rate Comparison in different re-sampling rate Different protected sub-carriers MIMO AIC

53. Protected spectrum 3 sub-carriers AIC R=4 Protected spectrum 5 sub-carriers AIC R=4

54. Protected spectrum 7 sub-carriers AIC R=4 Protected spectrum 9 sub-carriers AIC R=4

55. Protected spectrum 11 sub-carriers AIC R=4 Protected spectrum 13 sub-carriers AIC R=4

56. Picture parameter Axis explanation & Input Parameter re-sampling rate Vs AIC number Turn-off Vs AIC with different re-sampling rate Comparison in different re-sampling rate Different protected sub-carriers MIMO AIC

57. 2Tx AIC Protected spectrum 4 sub-carriers R=4 AIC 6 sub-carriers Channel? No

58. 2Tx AIC

59. Conclusion AIC 壓縮能力大約 100 ~ 130 dB AIC sub-carrier 不是越多越好，適用即可。越遠 的 sub-carrier 影響越小。

60. Reference Hirohisa Yamaguchi, “ Active Interference Cancellation Technique for MB-OFDM Cognitive Radio” 2004 Danijela Cabric, Shridhar Mubaraq Mishra, Robert W. Brodersen, “ Implementation Issues in Spectrum Sensing for Cognitive Radios” J. Mitola III, “Cognitive radio for flexible mobile multimedia communications,” in 1999 IEEE International Workshop on Mobile Multimedia Communications, 15-17 Nov. 1999, pp. 3-10. J. Mitola III, “Cognitive radio an integrated agent architecture for software defined radio,” PHD thesis, KTH Royal Institute of Technology, Stockholm, Sweden, 2000. Federal Communications Commission, “ Spectrum Policy Task Force,”Rep. ET Docket no. 02-135, Nov. 2002.

61. Simon Haykin, “Cognitive Radio: Brain-Empowered Wireless Communications” IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 23, NO. 2, FEBRUARY 2005