Revisiting Degrees of Freedom of Full-Duplex Systems with Opportunistic Transmission: An Improved User Scaling Law

It was recently studied how to achieve the optimal degrees of freedom (DoF) in a multi-antenna full-duplex system with partial channel state information (CSI). In this paper, we revisit the DoF of a multiple-antenna full-duplex system using opportunistic transmission under the partial CSI, in which...

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Main Authors: Haksoo Kim, Juyeop Kim, Sang Won Choi, Won-Yong Shin
Format: Article
Language:English
Published: MDPI AG 2018-03-01
Series:Entropy
Subjects:
Online Access:http://www.mdpi.com/1099-4300/20/3/160
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spelling doaj-c68a30f6342d449798ffd045a8732d042020-11-24T22:09:59ZengMDPI AGEntropy1099-43002018-03-0120316010.3390/e20030160e20030160Revisiting Degrees of Freedom of Full-Duplex Systems with Opportunistic Transmission: An Improved User Scaling LawHaksoo Kim0Juyeop Kim1Sang Won Choi2Won-Yong Shin3Affiliated Institute of ETRI, Daejeon 305-390, KoreaDepartment of Electronics Engineering, Sookmyung Women’s University, Seoul 04310, KoreaICT Convergence Research Team, Korea Railroad Research Institute, Eiwang 437-757, KoreaDepartment of Computer Science and Engineering, Dankook University, Yongin 16890, KoreaIt was recently studied how to achieve the optimal degrees of freedom (DoF) in a multi-antenna full-duplex system with partial channel state information (CSI). In this paper, we revisit the DoF of a multiple-antenna full-duplex system using opportunistic transmission under the partial CSI, in which a full-duplex base station having M transmit antennas and M receive antennas supports a set of half-duplex mobile stations (MSs) having a single antenna each. Assuming no self-interference, we present a new hybrid opportunistic scheduling method that achieves the optimal sum DoF under an improved user scaling law. Unlike the state-of-the-art scheduling method, our method is designed in the sense that the scheduling role between downlink MSs and uplink MSs is well-balanced. It is shown that the optimal sum DoF of 2 M is asymptotically achievable provided that the number of MSs scales faster than SNR M , where SNR denotes the signal-to-noise ratio. This result reveals that, in our full-duplex system, better performance on the user scaling law can be obtained without extra CSI, compared to the prior work that showed the required user scaling condition (i.e., the minimum number of MSs for guaranteeing the optimal DoF) of SNR 2 M − 1 . Moreover, the average interference decaying rate is analyzed. Numerical evaluation is performed to not only validate our analysis but also show superiority of the proposed method over the state-of-the-art method.http://www.mdpi.com/1099-4300/20/3/160degrees of freedom (DoF)full-duplex systemshybrid opportunistic schedulingpartial channel state information (CSI)user scaling law
collection DOAJ
language English
format Article
sources DOAJ
author Haksoo Kim
Juyeop Kim
Sang Won Choi
Won-Yong Shin
spellingShingle Haksoo Kim
Juyeop Kim
Sang Won Choi
Won-Yong Shin
Revisiting Degrees of Freedom of Full-Duplex Systems with Opportunistic Transmission: An Improved User Scaling Law
Entropy
degrees of freedom (DoF)
full-duplex systems
hybrid opportunistic scheduling
partial channel state information (CSI)
user scaling law
author_facet Haksoo Kim
Juyeop Kim
Sang Won Choi
Won-Yong Shin
author_sort Haksoo Kim
title Revisiting Degrees of Freedom of Full-Duplex Systems with Opportunistic Transmission: An Improved User Scaling Law
title_short Revisiting Degrees of Freedom of Full-Duplex Systems with Opportunistic Transmission: An Improved User Scaling Law
title_full Revisiting Degrees of Freedom of Full-Duplex Systems with Opportunistic Transmission: An Improved User Scaling Law
title_fullStr Revisiting Degrees of Freedom of Full-Duplex Systems with Opportunistic Transmission: An Improved User Scaling Law
title_full_unstemmed Revisiting Degrees of Freedom of Full-Duplex Systems with Opportunistic Transmission: An Improved User Scaling Law
title_sort revisiting degrees of freedom of full-duplex systems with opportunistic transmission: an improved user scaling law
publisher MDPI AG
series Entropy
issn 1099-4300
publishDate 2018-03-01
description It was recently studied how to achieve the optimal degrees of freedom (DoF) in a multi-antenna full-duplex system with partial channel state information (CSI). In this paper, we revisit the DoF of a multiple-antenna full-duplex system using opportunistic transmission under the partial CSI, in which a full-duplex base station having M transmit antennas and M receive antennas supports a set of half-duplex mobile stations (MSs) having a single antenna each. Assuming no self-interference, we present a new hybrid opportunistic scheduling method that achieves the optimal sum DoF under an improved user scaling law. Unlike the state-of-the-art scheduling method, our method is designed in the sense that the scheduling role between downlink MSs and uplink MSs is well-balanced. It is shown that the optimal sum DoF of 2 M is asymptotically achievable provided that the number of MSs scales faster than SNR M , where SNR denotes the signal-to-noise ratio. This result reveals that, in our full-duplex system, better performance on the user scaling law can be obtained without extra CSI, compared to the prior work that showed the required user scaling condition (i.e., the minimum number of MSs for guaranteeing the optimal DoF) of SNR 2 M − 1 . Moreover, the average interference decaying rate is analyzed. Numerical evaluation is performed to not only validate our analysis but also show superiority of the proposed method over the state-of-the-art method.
topic degrees of freedom (DoF)
full-duplex systems
hybrid opportunistic scheduling
partial channel state information (CSI)
user scaling law
url http://www.mdpi.com/1099-4300/20/3/160
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