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Average Spectral Efficiency

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

  • GLOBECOM – Rate adaptive hierarchical modulation assisted two-user opportunistic scheduling
    GLOBECOM '05. IEEE Global Telecommunications Conference 2005., 2020
    Co-Authors: Jahangir Hossain, Mohamed-slim Alouini, Vijay K. Bhargava

    Abstract:

    We propose and study a two best user opportunistic scheduling algorithm using discrete rate adaptive hierarchical constellations (known also as embedded, multi-resolution, or asymmetrical constellations). The key idea is to rely on hierarchical constellations to transmit information to the two best users opportunistically. The newly proposed scheme transmits information to single or two best users jointly considering the channel qualities of these users. We present expressions for the information transmission probability and the overall Average Spectral Efficiency [Bits/Sec/Hz] defined as the overall Average transmitted data rate per unit bandwidth for a specified number of users, Average carrier-to-noise ratio (CNR), and bit error rate (BER). Numerical results for an identical and independent (i.i.d.) fading environment, where the channel variation among the users is i.i.d., are presented. The results show that in such i.i.d. fading environment, our newly proposed discrete rate adaptive hierarchical modulation assisted two best user scheduling provides more frequent access to the information (almost double) without any Average Spectral Efficiency degradation compared to the classical single best user opportunistic scheduling.

  • IWCMC – A threshold-based multiple optical signal selection scheme for WDM FSO systems
    2017 13th International Wireless Communications and Mobile Computing Conference (IWCMC), 2017
    Co-Authors: Mohamed-slim Alouini, Young-chai Ko

    Abstract:

    In this paper, we propose a threshold-based-multiple optical signal selection scheme (TMOS) for free-space optical systems based on wavelength division multiplexing. With the proposed TMOS, we can obtain higher Spectral Efficiency while reducing the potential increase in complexity of implementation caused by applying a selection-based beam selection scheme without a considerable performance loss. Here, to accurately characterize the performance of the proposed TMOS, we statistically analyze the characteristics with heterodyne detection technique over independent and identically distributed Log-normal turbulence conditions taking into considerations the impact of pointing error. Specifically, we derive exact closed-form expressions for the Average bit error rate, and the Average Spectral Efficiency by adopting an adaptive modulation. Some selected results shows that the Average Spectral Efficiency can be increased with TMOS while the system requirement is satisfied.

  • Threshold-based multiple optical signal selection scheme for free-space optical wavelength division multiplexing systems
    IEEE OSA Journal of Optical Communications and Networking, 2017
    Co-Authors: Sung Sik Nam, Mohamed-slim Alouini, Lin Zhang, Young-chai Ko

    Abstract:

    We propose a threshold-based multiple optical signal selection scheme (TMOS) for free-space optical wavelength division multiplexing systems. With this scheme, we can obtain higher Spectral Efficiency while reducing the possible complexity of implementation caused by the beam-selection scheme and without a considerable performance loss. To characterize the performance of our scheme, we statistically analyze the operation characteristics under conventional detection conditions (i.e., heterodyne detection and intensity modulation/direct detection techniques) with log-normal turbulence while taking into consideration the impact of pointing error. More specifically, we derive exact closed-form expressions for the outage probability, the Average bit error rate, and the Average Spectral Efficiency while adopting an adaptive modulation. Some selected results show that TMOS increases the Average Spectral Efficiency while maintaining a minimum Average bit error rate requirement.

George K. Karagiannidis – One of the best experts on this subject based on the ideXlab platform.

  • GLOBECOM – Average Spectral Efficiency of Opportunistic QRD-Based Cyclic Prefixed Single-Carrier Cooperative Diversity Systems with Power Allocation
    2010 IEEE Global Telecommunications Conference GLOBECOM 2010, 2010
    Co-Authors: Theodoros A. Tsiftsis, George K. Karagiannidis

    Abstract:

    Due to higher peak-to-Average power ratio and higher power backing-off in OFDM relaying systems, a cyclic prefixed single-carrier cooperative diversity system is considered in this paper. Under the transmission power constraint, the joint optimal power allocation to the source and relay node is investigated.

  • Average Spectral Efficiency of opportunistic qrd based cyclic prefixed single carrier cooperative diversity systems with power allocation
    Global Communications Conference, 2010
    Co-Authors: Theodoros A. Tsiftsis, George K. Karagiannidis

    Abstract:

    Due to higher peak-to-Average power ratio and higher power backing-off in OFDM relaying systems, a cyclic prefixed single-carrier cooperative diversity system is considered in this paper. Under the transmission power constraint, the joint optimal power allocation to the source and relay node is investigated.

  • Average Spectral Efficiency of Opportunistic QRD-Based Cyclic Prefixed Single-Carrier Cooperative Diversity Systems with Power Allocation
    2010 IEEE Global Telecommunications Conference GLOBECOM 2010, 2010
    Co-Authors: Theodoros A. Tsiftsis, George K. Karagiannidis

    Abstract:

    Due to higher peak-to-Average power ratio and higher power backing-off in OFDM relaying systems, a cyclic prefixed single-carrier cooperative diversity system is considered in this paper. Under the transmission power constraint, the joint optimal power allocation to the source and relay node is investigated. For a two-hop decode-and-forward relaying protocol, the optimal power allocation is first obtained in the considered system, and then the opportunistic destination terminal selection is applied to improve the achievable Average Spectral Efficiency (ASE). Based on the proposed QR decomposition (QRD)-based receiver in the destination terminal, closed-form expressions for the maximum achievable ASE are derived. Simulation results verify the derived closed-form analytical expressions.

Young-chai Ko – One of the best experts on this subject based on the ideXlab platform.

  • IWCMC – A threshold-based multiple optical signal selection scheme for WDM FSO systems
    2017 13th International Wireless Communications and Mobile Computing Conference (IWCMC), 2017
    Co-Authors: Mohamed-slim Alouini, Young-chai Ko

    Abstract:

    In this paper, we propose a threshold-based-multiple optical signal selection scheme (TMOS) for free-space optical systems based on wavelength division multiplexing. With the proposed TMOS, we can obtain higher Spectral Efficiency while reducing the potential increase in complexity of implementation caused by applying a selection-based beam selection scheme without a considerable performance loss. Here, to accurately characterize the performance of the proposed TMOS, we statistically analyze the characteristics with heterodyne detection technique over independent and identically distributed Log-normal turbulence conditions taking into considerations the impact of pointing error. Specifically, we derive exact closed-form expressions for the Average bit error rate, and the Average Spectral Efficiency by adopting an adaptive modulation. Some selected results shows that the Average Spectral Efficiency can be increased with TMOS while the system requirement is satisfied.

  • Threshold-based multiple optical signal selection scheme for free-space optical wavelength division multiplexing systems
    IEEE OSA Journal of Optical Communications and Networking, 2017
    Co-Authors: Sung Sik Nam, Mohamed-slim Alouini, Lin Zhang, Young-chai Ko

    Abstract:

    We propose a threshold-based multiple optical signal selection scheme (TMOS) for free-space optical wavelength division multiplexing systems. With this scheme, we can obtain higher Spectral Efficiency while reducing the possible complexity of implementation caused by the beam-selection scheme and without a considerable performance loss. To characterize the performance of our scheme, we statistically analyze the operation characteristics under conventional detection conditions (i.e., heterodyne detection and intensity modulation/direct detection techniques) with log-normal turbulence while taking into consideration the impact of pointing error. More specifically, we derive exact closed-form expressions for the outage probability, the Average bit error rate, and the Average Spectral Efficiency while adopting an adaptive modulation. Some selected results show that TMOS increases the Average Spectral Efficiency while maintaining a minimum Average bit error rate requirement.

  • Maximum Spectral Efficiency of Amplify-and-Forward Cooperative Transmission with Multiple Relays
    IEEE Transactions on Wireless Communications, 2011
    Co-Authors: Jae-woo Kwon, Young-chai Ko, Hong-chuan Yang

    Abstract:

    In this paper, we propose a new amplify-and-forward (AF) cooperative transmission scheme with adaptive modulation to maximize overall system Spectral Efficiency. We quantify the Average Spectral Efficiency performance of the proposed scheme through statistical analysis based on an upper bound of the combiner output signal-to-noise ratio (SNR) and obtain the closed-form solutions for some practical scenarios of interest.