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Implementation of Self-Interference Cancellation Techniques for Full-Duplex Communication

전이중 통신을 위한 자기간섭 제거 기법 구현

  • Kim, Young-Jun (Department of Electrical and Information Engineering, Seoul National University of Science and Technology) ;
  • Shin, Jinjae (Department of Electrical and Information Engineering, Seoul National University of Science and Technology) ;
  • Cho, Hyundeok (Department of Electrical and Information Engineering, Seoul National University of Science and Technology) ;
  • Yun, Ji-Hoon (Department of Electrical and Information Engineering, Seoul National University of Science and Technology)
  • Received : 2016.01.19
  • Accepted : 2016.02.26
  • Published : 2016.03.31

Abstract

Full-duplex communication can enhance wireless capacity by enabling simultaneous transmission and reception of the signals on the same frequency spectrum. Such a benefit, however, is only achieved when strong self-interference is well canceled below a sufficient level. To achieve this goal, there have been several approaches for cancellation, each of which is combined with digital-domain cancellation for a higher gain. In this paper, we implement two self-interference cancellation techniques and integrate them with a software defined radio-based wireless communication testbed. Two cancellation techniques (antenna cancellation and noise subtraction) are implemented and the cancellation gain is measured via real experiments. The results show that the gain of the antenna placement technique highly depends on the placement of a receiving antenna and the highest gain is achieved at the expected point, and we show that combining the noise subtraction circuit with the antenna placement further improves the cancellation gain.

동일 주파수에서 신호의 송신과 수신을 동시에 수행하는 전이중 통신은 무선 링크 용량을 향상시킬 기술로 관심을 받고 있지만, 노드가 전송하는 시그널이 자신에게 간섭으로 작용하는 자기간섭을 억제해야 용량 이득을 달성할 수 있다. 본 논문에서는 자기간섭 제거 기법을 구현하고 이를 SDR(Software-Defined Radio) 기반의 송수신 시스템과 결합한 테스트베드 실험을 통해 제거 성능을 측정한다. 구현된 자기간섭 제거 기법은 안테나 배치 기법과 아날로그 신호 레벨에서 노이즈를 제거하는 회로 기법으로, 안테나 배치를 통한 기법의 동작 시 안테나 위치에 따른 자기간섭 제거 게인의 변화를 측정을 통해 보이고, 이 두 기법이 동시에 적용되었을 때 추가적인 게인을 얻을 수 있음을 보인다.

Keywords

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