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Mohamed-slim Alouini - One of the best experts on this subject based on the ideXlab platform.

  • Optimal Linear Precoding for Indoor Visible Light Communication System
    arXiv: Signal Processing, 2017
    Co-Authors: Houssem Sifaou, Ki-hong Park, Abla Kammoun, Mohamed-slim Alouini
    Abstract:

    Visible light communication (VLC) is an emerging technique that uses light-emitting diodes (LED) to combine communication and illumination. It is considered as a promising scheme for indoor wireless communication that can be deployed at reduced costs while offering high data rate performance. In this paper, we focus on the design of the downlink of a multi-user VLC system. Inherent to multi-user systems is the interference caused by the broadcast nature of the medium. Linear Precoding based schemes are among the most popular solutions that have recently been proposed to mitigate inter-user interference. This paper focuses on the design of the optimal Linear Precoding scheme that solves the max-min signal-to-interference-plus-noise ratio (SINR) problem. The performance of the proposed Precoding scheme is studied under different working conditions and compared with the classical zero-forcing Precoding. Simulations have been provided to illustrate the high gain of the proposed scheme.

  • ICC - Optimal Linear Precoding for indoor visible light communication system
    2017 IEEE International Conference on Communications (ICC), 2017
    Co-Authors: Houssem Sifaou, Ki-hong Park, Abla Kammoun, Mohamed-slim Alouini
    Abstract:

    Visible light communication (VLC) is an emerging technique that uses light-emitting diodes (LED) to combine communication and illumination. It is considered as a promising scheme for indoor wireless communication that can be deployed at reduced costs while offering high data rate performance. In this paper, we focus on the design of the downlink of a multi-user VLC system. Inherent to multi-user systems is the interference caused by the broadcast nature of the medium. Linear Precoding based schemes are among the most popular solutions that have recently been proposed to mitigate inter-user interference. This paper focuses on the design of the optimal Linear Precoding scheme that solves the max-min signal-to-interference-plus-noise ratio (SINR) problem. The performance of the proposed Precoding scheme is studied under different working conditions and compared with the classical zero-forcing Precoding. Simulations have been provided to illustrate the high gain of the proposed scheme.

Christos Masouros - One of the best experts on this subject based on the ideXlab platform.

  • ICC - Enhanced outage performance with adaptive Linear Precoding in cognitive radio downlink
    2012 IEEE International Conference on Communications (ICC), 2012
    Co-Authors: Faheem A. Khan, Christos Masouros, Tharmalingam Ratnarajah
    Abstract:

    In this paper, we investigate the outage performance of interference aided adaptive Linear Precoding in the downlink of a multiuser multiple-input-single-output (MISO) overlay cognitive radio (CR) network. While previous research studies on Linear Precoding techniques in CR network aim to limit or completely cancel the interference to the primary users while achieving maximum downlink throughput of the CR system, we here make use of adaptive Linear Precoding at the cognitive base station (CBS) to exploit the interference to the primary and the secondary systems. We show by analysis and simulations that the outage performance of the proposed Precoding technique is significantly enhanced in comparison to the conventional techniques.

  • Interference-Driven Linear Precoding in Multiuser MISO Downlink Cognitive Radio Network
    IEEE Transactions on Vehicular Technology, 2012
    Co-Authors: Faheem A. Khan, Christos Masouros, Tharmalingam Ratnarajah
    Abstract:

    We consider Linear Precoding in the downlink of a multiuser multiple-input-single-output (MISO) overlay cognitive radio (CR) network, wherein a primary base station (PBS) and a cognitive base station (CBS) share the same frequency band to transmit to a number of primary users (PUs) and secondary users. Conventionally, Linear Precoding techniques in a CR network aim to limit or completely cancel interference to the PUs while achieving maximum downlink throughput of the CR system. In this paper, we investigate novel adaptive Linear Precoding techniques at the CBS to exploit the interference to the primary and secondary systems, instead of its cancellation, by exploring the potential of making use of interference energy when the interference between the two systems is mutually constructive on an instantaneous basis. By doing so, the received signal-to-noise ratio (SNR) is enhanced by the signal energy gleaned from the constructive interference. In this direction, constructive-interference-based adaptive Linear Precoding techniques are proposed for the CR network, assuming a simple zero-forcing precoder at the PBS and noncausal knowledge of the primary message at the CBS. The presented analysis and simulations show that the proposed Precoding techniques outperform conventional techniques, as the CR transmission actively enhances the performance of the PUs through constructive interference while achieving significant throughput for its own transmission.

  • CogART - Interference driven Linear Precoding for cognitive radio downlink
    Proceedings of the 4th International Conference on Cognitive Radio and Advanced Spectrum Management - CogART '11, 2011
    Co-Authors: Faheem A. Khan, Christos Masouros, Tharmalingam Ratnarajah
    Abstract:

    We investigate Linear Precoding in the downlink of a multiuser multiple-input-single-output (MISO) cognitive radio (CR) system where cognitive users (CUs) share the spectrum with primary users (PUs). In previous studies, Linear Precoding techniques in CR network aim to limit or completely cancel the interference to the primary users while achieving maximum downlink throughput of the CR system. Here, we make use of interference energy when the interference between the primary and cognitive systems is mutually constructive on an instantaneous basis. By doing so, the received signal-to-noise ratio (SNR) is enhanced by the signal energy gleaned from the constructive interference. The presented analysis and simulations show that the proposed Precoding techniques outperform the conventional techniques, as the CR transmission actively enhances the performance of the primary users through constructive interference while achieving improved performance for its own transmission.

  • WCNC - A Throughput Enhancing Linear Precoding Scheme for the MIMO Downlink
    2010 IEEE Wireless Communication and Networking Conference, 2010
    Co-Authors: Christos Masouros, Emad Alsusa
    Abstract:

    A novel Linear Precoding scheme is proposed for the downlink of multiuser multiple input multiple output (MIMO) systems, that offers enhanced data throughput compared to conventional Precoding. The proposed technique is based on the fact that part of the instantaneous multiple access interference (MAI) inherent in a multiuser MIMO system adds constructively to the useful signal. It utilises this concept by applying partial Linear Precoding such that the destructive part is eliminated while the constructive part of MAI is preserved and exploited. By doing so, the effective signal to interference-plus-noise ratio (SINR) delivered to the mobile unit (MU) receivers is enhanced, without the need to invest in additional transmitted signal power at the MIMO base station (BS). The presented analysis and simulations verify that the proposed Precoding scheme significantly enhances the data throughput compared to conventional Precoding.

Hanyoung Jang - One of the best experts on this subject based on the ideXlab platform.

  • WCNC - Performance of Linear Precoding and user selection in IEEE 802.11ac downlink MU-MIMO system
    2014 IEEE Wireless Communications and Networking Conference (WCNC), 2014
    Co-Authors: Woochang Lim, Gibum Kim, Jinwoo Kim, Hyuncheol Park, Keunmoo Lee, Hanyoung Jang
    Abstract:

    IEEE 802.11ac is a next generation wireless local area network (WLAN) standard employing multi-user multiple-input multiple-output (MU-MIMO) scheme for the first time. Since Precoding and user selection schemes influence the performance of MU-MIMO transmission, accurate channel state information (CSI) is required to select users and obtain Precoding matrix. In this paper, we evaluate the performance of Linear Precoding schemes such as channel inversion (CI) and block diagonalization (BD) with limited CSI by using compressed feedback. We also describe the greedy user selection metrics and Linear Precoding schemes of low complexity. Our results compare the achievable sum-rate between the user selection metrics and provide the packet error rate (PER) performance under the realistic channel models.

Xiaohui Lin - One of the best experts on this subject based on the ideXlab platform.

  • Linear Precoding for Multiuser Visible-Light Communication With Field-of-View Diversity
    IEEE Photonics Journal, 2016
    Co-Authors: Renhai Feng, Mingjun Dai, Hui Wang, Bin Chen, Xiaohui Lin
    Abstract:

    The multiple-input–multiple-output (MIMO) indoor visible-light communication (VLC) system with multiple users, where several light-emitting diodes (LEDs) send messages to several photodiodes (PD), is studied. To enhance the diversity, each user is assumed to be equipped with multiple PDs with a different field of view. The objective is to minimize the LEDs' maximum power consumption subject to multiple constraints, including illumination constraint and capacity constraint. Under the assumption of maximum-ratio combining at the receivers, a Linear Precoding method is proposed. Detailed operation of this Precoding method includes two steps: First, with matrix transformation and semi-definite relaxation, the original nonconvex optimization problem is transformed into solvable convex optimization subproblems. Afterward, based on the solution of the subproblems, it is proved that a Linear Precoding solution can be reformulated using a rank-1 decomposition theorem. Numerical results show that our proposed scheme with different system parameters outperforms the traditional method.

Andreas F Molisch - One of the best experts on this subject based on the ideXlab platform.

  • asymmetric cooperation among wireless relays with Linear Precoding
    IEEE Transactions on Wireless Communications, 2008
    Co-Authors: Natasha Devroye, Neelesh B Mehta, Andreas F Molisch
    Abstract:

    Wireless relays extend coverage, improve spectral efficiency, and enhance reliability and rates of wireless cellular communication systems. In this work, we introduce the fundamental notion of asymmetric cooperation among cooperating relays in cellular downlinks - different relays are party to different but overlapping knowledge about the messages transmitted from the base station. We argue that asymmetric cooperation arises naturally in most two-phase protocols in which the base station first transmits information to multiple relays that then cooperatively forward the information to the recipient mobile stations in the cell. For a system in which two relays are of the decode-and-forward type and cooperate using Linear Precoding to communicate with two mobile stations, we formulate the general, but complicated, throughput optimization problem and derive several results that considerably simplify the optimization. We show that under different channel configurations and fairness criteria, asymmetric cooperation is often the throughput-maximizing option. Under typical configurations, a 20-30% throughput enhancement is achieved compared to conventional full-cooperation systems.