• Title, Summary, Keyword: Full-duplex

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Medium Access Control Protocols for Full-Duplex Communications in WLAN Systems: Approaches and Challenges (무선랜 시스템에서 전이중 통신을 위한 MAC 프로토콜 분석)

  • Kim, Wonjung;Song, Taewon;Kim, Taeyoon;Pack, Sangheon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.7
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    • pp.1276-1285
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    • 2015
  • Full-duplex communications have emerged as a key technology for next-generation wireless local area networks (WLANs). Although the key enabling technology for full-duplex communications is the self-interference cancellation (SIC) technique in the physical layer, the employment of full-duplex communications has huge potentials to substantially increase the throughput at the medium access control (MAC) layer. At the same time, full-duplex communications pose non-trivial challenges to the MAC protocol design. In this article, we first identify salient problems in supporting full-duplex communications in WLAN MAC protocols. After that, we survey the state-of-the art to address those problems and analyze their pros and cons. Finally, we present open research challenges to improve the effectiveness of full-duplex communications in WLANs.

Survey on MIMO Full-Duplex (MIMO Full-Duplex 기술 동향)

  • Yang, Hyun Jong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.7
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    • pp.1286-1292
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    • 2015
  • In this paper, a multi-input multi-output (MIMO) full-duplex system is addressed, where both the transmitter and receiver have multiple antennas. Fundamental problems of the MIMO full-duplex technique are discussed, and possible solutions are presented. In particular, the transceiver designs that have been reported in the literature are technically reviewed, and their problems are discussed investigating the feasibility of the full-duplex technique in commercialized systems such as LTE and WiFi.

Performance Analysis of Full Duplex on-regenerative Relay

  • Ban, Tae-Won;Jung, Bang-Chul
    • Journal of information and communication convergence engineering
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    • v.9 no.6
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    • pp.647-651
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    • 2011
  • In this letter, non-regenerative Amplify-and-Forward (AF) relay systems based on half and full duplex schemes are investigated and their performance is analyzed and compared in terms of outage probability. Although the AF relay systems have been widely investigated in many previous literatures, most of them adopted a half duplex scheme due to hardware limitation and mathematical tractability. To the best of our knowledge, this letter is the first study to investigate the performance of the full duplex AF relay system considering practical hardware limitations. In full duplex AF relay systems, it is important to secure the isolation between transmit and receive antennas. Our numerical and simulation results show that there exists a threshold point of the isolation gain that the full duplex relay system outperforms the half duplex relay system.

Precoding Algorithm and Capacity of Multiful Antennas Full-duplex Relay (다중 안테나 양방향 릴레이를 위한 프리코딩 기법 및 용량 분석)

  • Seong, Yun-Hyeon;Lee, Jong-ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.481-484
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    • 2009
  • In this paper, we suggest a precoding algorithm for full-duplex relay with multiple antennas. Because full-duplex relay performs transmission and reception at the same time in the same frequency band another existing half-duplex relay differently, self interference arise between transmit and receive antennas of relay. The proposed precoding algorithm eliminates self interference by block diagonalization algorithm and makes the relay perform full-duplex operation. Also we verify that full-duplex relay have improved channel capacity than existing half-duplex relay by computer simulation.

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Resource Allocation in Full-Duplex OFDMA Networks: Approaches for Full and Limited CSIs

  • Nam, Changwon;Joo, Changhee;Yoon, Sung-Guk;Bahk, Saewoong
    • Journal of Communications and Networks
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    • v.18 no.6
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    • pp.913-925
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    • 2016
  • In-band wireless full-duplex is a promising technology that enables a wireless node to transmit and receive at the same time on the same frequency band. Due to the complexity of self-interference cancellation techniques, only base stations (BSs) are expected to be full-duplex capable while user terminals remain as legacy half-duplex nodes in the near future. In this case, two different nodes share a single subchannel, one for uplink and the other for downlink, which causes inter-node interference between them. In this paper, we investigate the joint problem of subchannel assignment and power allocation in a single-cell full-duplex orthogonal frequency division multiple access (OFDMA) network considering the inter-node interference. Specifically, we consider two different scenarios: i) The BS knows full channel state information (CSI), and ii) the BS obtains limited CSI through channel feedbacks from nodes. In the full CSI scenario, we design sequential resource allocation algorithms which assign subchannels first to uplink nodes and then to downlink nodes or vice versa. In the limited CSI scenario, we identify the overhead for channel measurement and feedback in full-duplex networks. Then we propose a novel resource allocation scheme where downlink nodes estimate inter-node interference with low complexity. Through simulation, we evaluate our approaches for full and limited CSIs under various scenarios and identify full-duplex gains in various practical scenarios.

Recent Study on Interference Management for Full-Duplex Cellular Systems (전이중 셀룰라 시스템의 간섭 제어에 관한 최근 연구 동향)

  • Jeon, Sang-Woon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.7
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    • pp.1266-1275
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    • 2015
  • This review paper introduces recent results on interference management for full-duplex cellular systems. Interference management techniques for uplink-downlink cellular networks are frist introduced, which are closely related to those for full-duplex cellular systems. Self-interference suppression method for full-duplex radios and the corresponding modeling of full-duplex cellular systems are then explained. Even if self-interference is perfectly suppressed, there exists a new source of interference between full-duplex users for full-duplex cellular systems. Therefore, management of such user-to-user interference is of crucially importance to improve the capacity of full-duplex cellular systems. Recently, new interference management techniques for achieving the optimal sum degrees of freedom of full-duplex cellular systems have been proposed. In this review paper, these optimal interference management techniques are mainly introduced.

OFDMA FD-MAC Protocol Based on the Channel Information (채널정보 기반 OFDMA FD-MAC 프로토콜)

  • Cheon, Hye-Rim;Kim, Jae-Hyun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.3
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    • pp.451-458
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    • 2015
  • The deployment density of AP increases as well as the density WLAN stations due to increase of WLAN use and the real performance of WLAN is degraded. To improve the performance, there are many PHY/MAC technologies and OFDMA and full duplex are promising technologies among them. In conventional OFDMA WLAN MAC relate works, there are some limitations in terms of channel utilization and collision probability. Thus, it need to research for effective channel allocation protocol. Full duplex can transmit data on the same time and same frequency resource so it can allocate channel more flexible than half duplex. In this paper, we prose the OFDMA FD-MAC(Full Duplex MAC) protocol that it allocates the sub-channels based on the idle channel information for full duplex pair. In addition, it shows the throughput improvement by performance analysis.

Link selection based on switching between full-duplex and half-duplex modes

  • Kim, Sangchoon
    • ETRI Journal
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    • v.42 no.1
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    • pp.17-25
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    • 2020
  • Multiple-input multiple-output systems can achieve a full sum rate (SR) via full duplex (FD). However, its performance is degraded by self-interference (SI) that occurs between the transmitter and receiver at the same node and thus is constrained by error floors. Conversely, half duplex (HD) can avoid the SI albeit at lower spectral efficiency, and the slope of its error curve is determined by the diversity order. In this study, a link selection scheme based on switching between FD and HD is examined as a simple method to improve the bit error rate (BER) performance of FD systems. In the proposed link selection algorithm, either FD or HD is selected based on the received minimum distance and signal-to-interference plus noise ratio. Simulation results indicate that the proposed hybrid FD/HD switching system offers significant BER performance improvement when compared with that of the conventional FD and FD based on only the received minimum distance under the same fixed SR. Under relatively sufficient SI cancellation, it is demonstrated to outperform the HD with a diversity advantage in low and medium signal-to-noise ratio region.

전이중 셀룰러 망의 자유도에 관한 연구

  • Chae, Seong-Ho;Im, Seong-Hun;Jeon, Sang-Un
    • Information and Communications Magazine
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    • v.32 no.5
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    • pp.65-72
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    • 2015
  • 본고에서는 기지국이 Full duplex를 지원하는 셀룰러 망의 자유도(Degrees of freedom) 에 관한 최근 연구 결과를 소개한다. 구체적으로 단말이 Half duplex로 동작하는 환경과 단말이 Full duplex로 동작하는 환경 각각의 경우에 대해 얻을 수 있는 최적의 자유도에 대해 살펴본다. 최근에 각각의 환경에 대해 최적의 자유도가 완벽히 규명되었다. 기지국이 Full duplex 동작을 지원할 경우, 단말의 수가 기지국의 안테나 수에 비해 충분히 많다면, 기지국이 Half duplex 로 동작하는 기존의 셀룰러 네트워크에 비해 최대 두 배 자유도 향상을 달성할 수 있다.

Outage Probability Analysis of Full Duplex Relay with Decode and Forward Protocol (복호 후 전달 방식을 사용하는 전이중 통신 릴레이 시스템에서의 오수신 확률 성능 분석)

  • Kwon, Tae-Hoon;Lim, Sung-Mook;Park, Sung-Soo;Hong, Dae-Sik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.6A
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    • pp.568-576
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    • 2010
  • In this paper, we analyze the outage probability of full duplex relay (FDR) with decode-and-forward (DF) protocol is derived under fading channels. The fading channel for source-relay link is assumed to be Rician fading to consider the infrastructured fixed relay with line of sight (LOS) propagation, and the other fading channels are assumed to be Rayleigh fading. Based on this analytical result, we provide the criterion that FDR shows a lower outage probability than HDR to consider the interference problem and the resource efficiency improvement by full duplex (FD) operation. The accuracy of the analysis is confirmed throughout the simulation results.