The Journal of Korean Institute of Communications and Information Sciences (한국통신학회논문지)

The Korean Institute of Commucations and Information Sciences (한국통신학회)
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Fixed-complexity Sphere Encoder for Multi-user MIMO Systems

다중 사용자 MIMO 시스템을 위한 고정 복잡도를 갖는 스피어 인코더

  • 마나르 모하이센 (인하대학교 정보통신대학원 이동통신연구실) ;
  • 한동걸 (인하대학교 정보통신대학원 이동통신연구실) ;
  • 장경희 (인하대학교 정보통신대학원 이동통신연구실)
  • Received : 2010.03.18
  • Accepted : 2010.07.01
  • Published : 2010.07.31
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Abstract

In this paper, we propose a fixed-complexity sphere encoder (FSE) for multi-user MIMO (MU-MIMO) systems. The Proposed FSE accomplishes a scalable tradeoff between performance and complexity. Also, because it has a parallel tree-search structure, the proposed encoder can be easily pipelined, leading to a tremendous reduction in the precoding latency. The complexity of the proposed encoder is also analyzed, and we propose two techniques that reduce it. Simulation and analytical results demonstrate that in a $4\times4$ MU-MIMO system, the complexity of the proposed FSE is 16% that of the conventional QRD-M encoder (QRDM-E). Also, the encoding throughput of the proposed endoder is 7.5 times that of the QRDM-E with tolerable degradation in the BER performance, while achieving the optimum diversity order.

본 논문에서는 다중 사용자 MIMO 시스템을 위한 고정 복잡도를 갖는 스피어 인코더 (FSE)를 제안하고, FSE의 복잡도를 감소시키는 2가지 방법을 제시한다. FSE는 성능과 복잡도 간의 트레이드오프 관계를 적응적으로 조절할 수 있고, 병렬의 트리 탐색구조를 적용함으로써 프리코딩 지연을 상당히 감소시킬 수 있다. $4\times4$ 다중 사용자 MIMO 시스템에서 시뮬레이션을 수행한 결과, 제안한 FSE는 QRDM 인코더 (QRDM-E)에 비하여 작은 BER 성능 감소를 가져오지만 최적의 다이버시티 오더를 달성함과 더불어 일반적인 QRDM-E 복잡도의 16%정도만을 갖고, 인코딩 처리량(throughput)이 7.5배 향상됨을 확인하였다.

Keywords

References

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