• 한국군사과학기술학회지
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• 제9권4호
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• pp.32-38
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• 2006

In this paper a sequence estimator of CDMA communication system is suggested. A sequence estimator uses Galois Field operation. A sequence estimator can provide another CDMA pilot signal which is un-modulated spreaded signal. A estimated sequence signal and received signal have no correlation. Tow signals can be summed using MRC(maximal ratio combine) method. The stronger signal can be added as a larger ratio, but the weaker signal can be added as a smaller ratio. We can distinguish strong signal using SNR estimator. Therefore it is possible to receive an additional pilot signal, and to support more reliable communications by using sequence estimator.

• 한국통신학회논문지
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• 제25권3A호
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• pp.391-398
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• 2000

In this paper, MRC(Maximum Ratio Combine) diversity, (23, 12) Golay code, (7, 5) Reed-Solomon code, and (3, 1) majority selection code are employed to improve the performance of DS/CDMA BRSK in Nakagami fading channel. and MRC diversity combined with other coding techniques is suggested, with which, the performance of DS/CDMA BRSK is compared and analyzed. Also, system required Eb/N0 to meet BER=10-5 for multi user data communication is obtained according to each techniques. From the results, when each techniques is employed to DS/CDMA BRSK system. coding employed system shows better performance than diversity employed system. Especially, Golay code shows better performance than oter codes. also MRC diversity is employed, the number of multiple access user to meet data communication requirement of BER=10-5 can accomodate up to 8 users. and when each code is employed, Golay code, majority selection code, and Reed-Solomon code shows the capacity of 14, 12, and 10 user respectively. But MRC diversity combined with coding techniques can reduce restriction of multiple access user. However, it is desirable these combined technique are employed according to service types and requirements provided.

• 한국정보통신학회논문지
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• 제6권8호
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• pp.1234-1240
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• 2002

본 논문에서는 Nakagami 페이딩 채널 특성의 이동 통신 환경에서 정보 데이터를 PN 시퀀스로 대역 확산시켜 BPSK 변조를 취한 CDMA 시스템에 MRC 다이버시티와 반복 전송(다수결 선택)이나 부호화 기법을 다양하게 결합하였을 때의 블록 오율 성능 향상에 대하여 분석한다. 분석 결과로써, 부호화는 다이버시티 기법보다 더 효과적인 성능 향상을 보였다. 그러나 부호화는 더 넓은 주파수 대역을 필요로 하게 된다. 또한 MRC 다이버시티와 부호화 기법을 결합하였을 때 성능 개선이 크게 향상되었다.