적응적 LNA의 최적 설계에 의한 IMT-2000 수신시스템 성능 개선 = Improvement of IMT-2000 Receiver Performance Based on the Optimization of an Adaptive LNA

다국어 초록 (Multilingual Abstract)

To improve the peformances of a IMT-2000 receiver system such as out-of-band blocking characteristics, spurious response attenuation and intermodulation characteristics, LNA_On or LNA_Bypass within the system have been used. The IIP3 parameter can be improved, but total noise indexes and the CNR parameter value may decrease, and, due to increased FER of receiving sensitivity, a decrease in communication quality may occur accompanied by call-drop. This study presented a design technique to optimize the performance of the WCDMA receiver system. The technique involves using adaptive LNA, and inserting it based on the interactions between parameters of IIP3, NF, and CNR. When this study applied the optimized values of LNA parameter to simulate the receiver, the performance of intermodulation spurious response attenuation showed improvement greater than when LNA_On was applied, noise index was greatly improved compared to LNA_Bypass applications. This suggests that an optimized design technique contributed to improved communication quality of the IMT-2000 receiver system.
This study used adaptive LNA based on the interaction between IIP3, NF and CNR parameters to optimize the performance of the IMT-2000 system receiver. It demonstrated that the technique suggested through the simulation can improve communication quality compared with LNA_On/bypass type receiver. In order to improve intermodulation spurious response attenuation performance of the IMT-2000 receiver, when LNA was bypassed as in DCS and PCS receivers, the IIP3 parameter value was 11.41dBm and the margin was 30.9dBm. Through the results it was demonstrated that intermodulation spurious response attenuation performance improved, but the whole NF was 20.95dB, which deviated from the standard to -11.81dB and receiving sensitivity rapidly decreased and a call-drop phenomenon happened. In general, as the parameter characteristics of NF and CNR remarkably decreased, it was proved that approximately at-85dBm received power, a call-drop happened. To improve the problems of the LNA_Bypass, parameters based on adaptive LNA gain were calculated, and as a result, when the gain of LNA was 9.5dB, NF was 2.0dB and IIP3 had an optimal value of 10.0dBm. Therefore, this study designed the optimized receiver by applying the optimally adaptive LNA parameter value and found that the IIP3 of the whole system was -3.10dBm and the margin was about 16.39dBm. Intermodulation spurious response attenuation peformance was more improved compared with the case LAN_on, and NF was 8.87dB, much more improved than when LNA_Bypass was applied. Therefore, it was demonstrated that improved parameter values of NF and CNR contributed to the better performance of receiving sensitivity than when the LNA_Bypass was applied. Through the results of the simulation, it was proved that the IMT-2000 system receiver with adaptive LNA provided superior communication quality.

목차 (Table of Contents)

• 목차 = ⅰ
• 도목차 = ⅱ
• 표목차 = ⅳ
• 약어목록 = ⅴ
• ABSTRACT = ⅶ
• Ⅰ. 서론 = 1
• Ⅱ. 이동통신 수신시스템 = 4
• A. 수신시스템 구성 = 7
• 1. 고주파 신호 변환부 = 7
• 2. 디지털 신호 처리부 = 12
• B. 수신시스템 성능 규격 분석 = 16
• 1. 수신감도 = 16
• 2. 단일 톤 둔감도 = 23
• 3. 상호변조에 의한 스퓨리어스 응답 감쇄 = 25
• Ⅲ. Adaptive LNA의 최적 설계에 의한 이동통신 수신시스템 성능 개선 = 34
• A. LNA에 영향을 미치는 수신 성능 파라미터 분석 = 34
• B. Adaptive LNA를 적용한 설계 알고리즘 = 37
• 1. DCS 수신시스템 최적 설계 = 37
• 2. PCS 수신시스템 최적 설계 = 43
• 3. IMT-2000 수신시스템 최적 설계 = 49
• Ⅳ. 적응적 LNA 파라미터 실험 = 57
• Ⅴ. 결론 = 68
• 참고문헌 = 70