Journal of the Institute of Electronics Engineers of Korea TC (대한전자공학회논문지TC)

The Institute of Electronics and Information Engineers (대한전자공학회)
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Viterbi Decoder-Aided Equalization and Sampling Clock Recovery for OFDM WLAN

비터비 복호기를 이용한 OFDM-WLAN의 채널등화 및 샘플링 클럭추적

  • Published : 2005.05.01
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Abstract

IEEE 802.11a is a standard for the high-speed wireless local area network (WLAN), supporting from 6 up to 54 Mbps in a 5 GHz band. We propose a channel equalization algerian and a sampling clock recovery algorithm by utilizing the Viterbi decoder output of the IEEE 802.11a WLAN standard. The proposed channel equalizer adaptively compensates channel variations. The proposed system uses re-encoded Viterbi decoder outputs as reference symbols for the adaptation of the channel equalizer. It also extracts sampling phase information with the Viterbi decoder outputs for fine adjustment of the sampling clock. The proposed sampling clock recovery and equalizer are more robust to noise and frequency selective fading environments than conventional systems using only four pilot samples.

OFDM(orthogonal frequency division multiplexing) 변조를 이용한 WLAN(wireless local area network) 시스템은 고속 무선 데이터 통신을 위한 대표적 수단으로 전송률의 향상을 위해 활발히 연구되고 있다. 본 논문에서는 WLAN의 정확한 채널 등화와 샘플링 클럭 추적을 위하여 비터비 복호기 출력을 이용한 등화 및 샘플링 클럭 추적 알고리듬을 제안한다. 이 알고리듬은 파일럿 신호를 이용하여 대략의 클럭 주파수 복원과 채널등화를 수행한 후 비터비 복호기의 출력을 다시 부호화하여 등화 및 샘플링 클럭의 추적에 이용하는 알고리듬이다. 제안한 알고리듬의 우수성을 ETSI WLAN 채널 환경에서 컴퓨터 모의실험을 통하여 보였다.

Keywords

References

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