Design of an enhanced SIR measurement algorithm for WCDMA mobile station Modem

WCDMA 단말 모뎀을 위한 개선된 SIR 측정 알고리즘 설계

  • 한정수 (성균관대학교 정보통신공학부) ;
  • 도주현 (성균관대학교 정보통신공학부) ;
  • 최형진 (성균관대학교 정보통신공학부)
  • Published : 2005.02.28

Abstract

In this paper, we propose an enhanced SIR measurement algorithm for WCDMA mobile station modem. The proposed algorithm minimizes processing delay by applying velocity estimation-based channel estimator with IIR filter and reduces measured SIR offset by compensating attenuated signal power by using pilot channel(CPICH) in fading channel environment. To improve stability of SIR measurement, we also adopt an IIR filter which can properly reflect variation of fading channel in signal and interference power measurement. We prove that the proposed algorithm outperforms conventional SIR measurement algorithm in mean and jitter of measured SIR. Computer simulation shows that performance results using the proposed algorithm have improvement of approximately 8dB for measured mean and 2dB for measured jitter in the wireless mobile channel, especially in fast mobile speed environment.

본 논문에서는 WCDMA(Wideband Code Division Multiple Access) 단말 모뎀을 위한 개선된 SIR 측정 알고리즘을 제안한다. 제안된 알고리즘은 속도 적응형 IIR 타입의 channel estimator를 적용함으로써 DPCH(Dedicated Physical Channel)의 채널 보상으로 인한 처리 지연을 최소화하였으며, 파일럿 채널인 CPICH(Common Pilot Channel)를 사용하여 페이딩 채널 환경에서 발생하는 신호 전력 감쇄를 보상함으로써 페이딩 환경에서 SIR 측정시 발생하는 SIR 측정 오차를 대폭 감소시켰다. 또한 fading의 변화를 적절히 반영할 수 있도록 IIR 필터를 신호 전력 및 간섭 전력 측정 시에 추가함으로써 SIR 측정에 대한 안정도를 향상시켰다. 제안된 알고리즘과 기존의 SIR 측정 알고리즘과의 성능 비교를 통하여 무선 이동 채널, 특히 고속 이동체 환경에서 제안된 알고리즘의 측정된 SIR의 mean은 최대 약 8dB, jitter는 약 2dB의 향상된 우수한 성능을 보임을 입증하였다.

Keywords

References

  1. Ariyavisitakul and Li. Fing. Chang, 'Signal and Interference Statistics of a CDMA System with Feedback Power Control,' IEEE Trans. Comm., Vol. 41, Issue. 11, pp.1626-1634, Nov. 1993 https://doi.org/10.1109/26.241743
  2. Sang-Mun Lee, Hyung-Jin Choi, 'An Efficient SIR Estimation and Channel Estimation Algorithm considering Power contol in CDMA Systems,' 제 25권, 7호, 한국통신학회, pp.1194-1195, July 2000
  3. Shunsuke Seo, Tomohiro Dohi and Fumiyuki Adachi, 'SIR-Based Transmit Power Control of Reverse Link for Coherent DS-CDMA Mobile Radio,' IEICE Trans. Comm., Vol. E81-B, No.7, pp1508-1516, July 1998
  4. Fahrner, Dieterich and Fray, 'SIR estimation for fast power control for FDD-UMTS,' IEEE conf. on VTC, Vol. 2, 24-28, pp1274-1278, Sept. 2002
  5. Kenichi Higuchi, Hidehiro Andoh, Koichi Okawa and Mamoru Sawahashi, 'Experimental Evaluation of Combined Effect of Coherent Rake Combining and SIR-Based Fast Transmit Power Control for Reverse Link of DSCDMA Mobile Radio,' IEEE JSAC, Vol.18, No.8, pp.1526-1535, Aug. 2000
  6. Joo-Hyun-Do, Yang-Soo-Park and Hyung-Jin Choi, 'Velocity Estimation-Based Channel Estimation for WCDMA Forward Link Receiver,' IEEE TENCON, November 2004
  7. 3GPP Technical Specification Group Radio Access Network TS. 25.104, 25.211, 25.213 Release 2003