Retransmission Scheme with Equal Combined Power Allocation Using Decoding Method with Improved Convergence Speed in LDPC Coded OFDM Systems

Abstract

본 논문은 type I 혼합-자동 반복 요구 (hybrid automatic repeat request: H-ARQ) 시스템에서 저밀도 패리티 검사 (low-density parity-check: LDPC)로 부호화된 직교 주파수 분할 다중화 (orthogonal frequency division multiplexing: OFDM) 서브프레임의 전송 순서를 균등 결합 전력이 할당되도록 조정한 재전송 방법 ABSTRACTIn this paper, we introduce the low-density parity-check (LDPC) coded orthogonal frequency division multiplexing (OFDM) subframe reordering scheme [7] for achieving equal combined power allocation in type I hybrid automatic repeat request (H-ARQ) systems and analyze the performance improvement by using the channel capacity. Also, it is confirmed that the layered decoding [4] for subframe reordering scheme in H-ARQ systems gives faster convergence speed. It is verified from numerical analysis that a subframe reordering pattern having larger channel capacity shows better bit error rate (BER) performance. Therefore the subframe reordering pattern achieving equal combined power allocation for each subframe maximizes the channel capacity and outperforms other subframe reordering patterns. Also, it is shown that the subframe reordering scheme for achieving equal combined power allocation gives better performance than the conventional Chase combining scheme without increasing the decoding complexity.※ 본 논문은 2011년 울산과학대학교 교내학술연구비 지원에 의해 수행된 연구 결과입니다. 주저자：울산과학대학교 전기전자공학부, mhjang@uc.ac.kr, 종신회원