Journal of the Institute of Electronics and Information Engineers (전자공학회논문지)

The Institute of Electronics and Information Engineers (대한전자공학회)
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Optimization of the Number of Active Antennas for Energy-Efficiency in the MIMO Broadcast Channel

다중 사용자 다중 안테나 하향링크 채널에서 에너지 효율 향상을 위한 기지국 활성 안테나 수 최적화 기법

  • Choi, Seungkyu (Department of Electrical and Electronic Engineering, Yonsei University) ;
  • Kim, Dohoon (Korea Electronics Technology Institute) ;
  • Lee, Chungyong (Department of Electrical and Electronic Engineering, Yonsei University)
  • Received : 2014.01.17
  • Accepted : 2014.04.24
  • Published : 2014.05.25
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Abstract

We introduce a number of antenna optimization problem for the zero-forcing beamforming (ZFBF) scheme to enhance energy-efficiency (EE) of the multiple-input-multiple-output broadcast channel. For proposed optimization problem, we assume an instantaneous channel gain of the ZFBF scheme as an average channel gain, given by $N_a-K+1$, in order to reduce a computational complexity of finding the number of active antennas $N_a$. Then, we convert a fractional-form objective function into a subtractive-form, and find a solution of $N_a$ and the maximum EE by an iterative process. Simulation results show that the maximum EE value obtained by proposed algorithm is almost identical to the optimal EE value by the exhaustive search method.

본 논문에서는 다중 사용자 다중 안테나 하향링크 채널에서 에너지 효율을 향상시키기 위하여 zero-forcing beamforming (ZFBF) 전처리 필터 기반의 기지국 활성 안테나 수 최적화 기법을 제안한다. 제안하는 기법에서는 최적의 안테나 수를 찾는 연산과정의 복잡도를 줄이기 위하여 사용자의 순시 채널 이득 대신 ZFBF의 평균 채널 이득을 사용한다. 그리고 분수함수 형태의 목적함수를 차를 이용한 목적함수로 변환하여 최적의 안테나 수와 최대 에너지 효율을 찾는 과정을 반복 수행하여 문제를 해결한다. 모의실험을 통해 제안하는 기법의 에너지 효율은 exhaustive search 방법으로 찾은 최대 에너지 효율과 거의 동일함을 확인한다.

Keywords

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