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Iterative decoding and channel parameter estimation algorithms for repeat-accumulate codes
Oh, Wangrok,Cheun, K. Institute of Electrical and Electronics Engineers 2005 IEEE transactions on communications Vol.53 No.10
The sensitivity of the iterative decoder for repeat-accumulate (RA) codes to carrier phase and channel signal-to-noise ratio estimation errors is investigated, and efficient algorithms to estimate and correct these errors are developed. The behavior of RA codes with imperfect channel estimation is different from that of turbo codes, and correction algorithms specific to RA codes must be formulated. The proposed algorithms use the soft information generated within the iterative decoder, and thus, are not only hardware-efficient, but also offer excellent performance.
180°Rotationally Invariant Repeat-Accumulate Codes
OH, Wangrok,CHEUN, Kyungwhoon The Institute of Electronics, Information and Comm 2009 IEICE TRANSACTIONS ON COMMUNICATIONS - Vol.92 No.5
<P>In digital communication systems employing binary phase-shift keying and non-data-aided carrier phase recovery, a 180°carrier phase ambiguity is inevitable. Here, we propose a simple modification to the standard regular repeat-accumulate (RA) code structure by exploiting the differential encoding inherent to the inner encoder of RA codes resulting in codes that are 180°rotationally invariant. The proposed code structure exhibit performance virtually identical to that of standard regular RA codes with zero carrier phase offset under both zero and 180°carrier phase offsets with negligible additional hardware complexity.</P>
케이블 모델 상향링크에 적합한 CAZAC sequence를 이용한 coarse timing recovery의 두 알고리즘 비교
하현주(Hyunju Ha),오왕록(Wangrok Oh),김환우(Whanwoo Kim) 대한전자공학회 2007 대한전자공학회 학술대회 Vol.2007 No.7
As Cable Network is developing for 2-way high speed data service, it should be developed to transfer high speed data using limited bandwidth. If QAM is using for this, synchronization algorithms become important system parameters. In this paper, we present two methods of coarse timing recovery using CAZAC sequence for cable modem uplink.
ECMA 표준에 기반한 Multi-Gigabit Packet 수신기 알고리듬 설계 및 구현
이용욱(Yongwook Lee),오왕록(Wangrok Oh) 대한전자공학회 2009 電子工學會論文誌-TC (Telecommunications) Vol.46 No.3
60 ㎓ 대역에서 multi-gigabit 전송률을 달성하기 위하여 제안된 ECMA 표준은 프리앰블과 데이터 부분으로 구성된 버스트 (burst)를 통하여 데이터 송수신을 수행하며 프리앰블과 데이터 부분에서는 동작 모드에 따라 다양한 변조 방식이 사용된다. 따라서 다양한 변조 방식을 지원할 수 있는 수신 알고리듬의 설계가 필수적이다. 본 논문에서는 ECMA 표준 중 DBPSK (Differential Binary Phase Shift Keying)와 DQPSK (Differential Quadrature Phase Shift Keying) 그리고 OOK (On-Off Keying) 변조 방식을 지원하는 multi-gigabit packet 송수신 시스템을 위한 수신 알고리듬을 설계하였다. 설계된 수신 알고리듬은 동일한 구조 및 동작 방식을 통하여 고려한 모든 변조 방식들을 지원할 수 있을 뿐만 아니라 하드웨어 구현 복잡도가 낮은 장점을 지닌다. In this paper, we propose the receiver algorithms suitable for the ECMA standard proposed for multi-gigabit packet transmission in 60 ㎓ band. In the ECMA standard, various modulation schemes are used for system flexibility. Hence, it is crucial to develop receiver algorithms supporting various modulation schemes with an uniform hardware structure. In this paper, we propose the receiver algorithms supporting DBPSK, DQPSK and OOK modulation schemes simultaneously. The proposed algorithms are not only hardware efficient but also support various modulation schemes with an uniform hardware structure.