著者

小松 和暉 宮路 祐一 上原 秀幸

出版者

IEEE

雑誌

IEEE Transactions on Wireless Communications = IEEE Transactions on Wireless Communications (ISSN:15361276)

巻号頁・発行日

vol.17, no.6, pp.3768-3780, 2018-06

被引用文献数

24

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This paper presents a basis function selection technique of a frequency-domain Hammerstein digital selfinterference canceller for in-band full-duplex communications. The power spectral density (PSD) of the nonlinear selfinterference signal is theoretically analyzed in detail, and a nonlinear self-interference PSD estimation method is developed. The proposed selection technique decides on the basis functions necessary for cancellation and relaxes the computational cost of the frequency-domain Hammerstein canceller based on the estimated PSD of the self-interference of each basis function. Furthermore, the convergence performance of the canceller is improved by the proposed selection technique. Simulation results are then presented, showing that the proposed technique can achieve similar cancellation performance compared with the original frequency-domain Hammerstein canceller and a time-domain nonlinear canceller. Additionally, it is shown that the proposed technique improves the computational cost and the convergence performance of the original frequency-domain Hammerstein canceller.

著者

宮路 祐一 上原 秀幸 大平 孝

出版者

電子情報通信学会

雑誌

電子情報通信学会技術研究報告 (ISSN:09135685)

巻号頁・発行日

vol.108, no.151, pp.25-30, 2008-07-24

被引用文献数

4

著者

小松 和暉 宮路 祐一 上原 秀幸

出版者

IEEE

雑誌

IEEE Wireless Communications and Networking Conference (WCNC), San Francisco, CA, 2017 = IEEE Wireless Communications and Networking Conference (WCNC), San Francisco, CA, 2017 (ISSN:15582612)

巻号頁・発行日

pp.1-6, 2017

被引用文献数

11

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In-band full-duplex communications have been spotlighted because they can double the spectral efficiency of the current wireless communication systems. However, it is necessary to mitigate the self-interference (SI). Currently, several time-domain and frequency-domain SI cancellers have been proposed. Timedomain SI cancellers are based on the parallel Hammerstein (PH) model, and they have good flexibility with high computational cost. In contrast, frequency-domain SI cancellers can achieve high cancellation performance with low computational cost but they have less flexibility than time-domain PH based SI cancellers. In this paper, we propose a frequency-domain SI canceller based on the PH model. The proposed scheme estimates the frequency response of the SI channel and regenerates SI signals by the overlap-save method. Therefore, the computational complexity of the proposed scheme is less than time-domain PH based SI canceller. The performance of the proposed scheme is assessed by equivalent baseband signal simulations of a fullduplex transceiver. As a result, the proposed scheme achieves high SI cancellation as the time-domain PH based SI canceller with low computational cost. In addition, the convergence performance of the proposed scheme is faster than the time-domain scheme.

著者

小松 和暉 宮路 祐一 上原 秀幸

出版者

IEEE

雑誌

IEEE Transactions on Wireless Communications = IEEE Transactions on Wireless Communications (ISSN:15361276)

巻号頁・発行日

vol.19, no.7, pp.4424-4438, 2020-07

被引用文献数

34

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This paper presents an iterative estimation and cancellation technique for nonlinear in-band full-duplex transceivers with IQ imbalances and amplifier nonlinearities. The estimation process of the proposed scheme consists of three stages, namely, the channel response estimation, IQ imbalance estimation, and power amplifier and low-noise amplifier (LNA) nonlinearities estimation. For the estimation of the parameters and improvement of the accuracy, distortions are compensated by cancellation or inversion with the latest estimated parameters. On the one hand, the channel response is estimated on the time domain; on the other hand, the IQ imbalance and nonlinearities are estimated on the frequency domain for a more straightforward estimation and superior accuracy. In the cancellation process of the proposed scheme, the received signal is compensated with the estimated parameters of the LNA and receiver IQ imbalance before cancellation because the desired signal is received with a high-power self-interference and is distorted by the radiofrequency receiver impairments. Simulation results show that the proposed technique can achieve higher cancellation performance compared with the Hammerstein canceller when the LNA is saturated by the self-interference. Additionally, the performance of the proposed canceller converges much faster than that of the Hammerstein canceller.

著者

山川 太一 宮路 祐一 上原 秀幸

出版者

一般社団法人情報処理学会

雑誌

研究報告ユビキタスコンピューティングシステム(UBI) (ISSN:09135685)

巻号頁・発行日

vol.2013, no.43, pp.1-5, 2013-05-09

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アドホックネットワークは多様な端末によって構成されるため,全方位性アンテナを搭載した端末 (全方位性端末) と,可変指向性アンテナを搭載した端末 (指向性端末) が混在した環境を許容する必要がある.しかし,このような環境における難聴や Head-of-Line(HOL) ブロッキングのような問題は,これまでに報告されていない本研究では,異種アンテナ混在アドホックネットワークにおいて,指向性端末が難聴となることによって全方位性端末で HOL ブロッキング問題が発生することを示す.この問題を解決するため,送信端末は難聴によって CTS パケットが受信できなかったとき,キューの中にある宛先の異なるパケットを先に送信する,日和見的なメディアアクセス制御手法を提案する.難聴は宛先が指向性端末のとぎのみに発生する.そこで,提案手法は宛先端末のアンテナの種類を用いて,他の宛先へのパケットを先に送信するかを決める.計算機シミュレーションから,提案手法は,IEEE 802.11DCF に比べて,スループットが約 28%向上した.Ad-hoc networks have terminals with various antenna capabilities such as omni-directional antenna and directional one. However, in ad-hoc networks with heterogeneous antennas, the Medium Access Control (MAC) layer problems such as deafness and Head-of-Line (HOL) blocking problem are not discussed. In this study, we argue HOL blocking problem due to deafness in ad-hoc networks with heterogeneous antennas. For solving the problem, we propose an opportunistic MAC protocol. In this protocol, if a sender does not receive CTS frame because of deafness, it attempts transmission to other destination. Deafness occurs only if the destination has directional antenna. The proposed MAC protocol uses the antenna type of the destination for determining whether the sender transmits to other destination or not. As a simulation result, the proposed MAC protocol achieves about 28% higher throughput than IEEE 802.11 DCF.