The Experts below are selected from a list of 31185 Experts worldwide ranked by ideXlab platform

Robert W. Heath - One of the best experts on this subject based on the ideXlab platform.

  • GLOBECOM - Optimizing the Target Error Rate for Link Adaptation
    2015 IEEE Global Communications Conference (GLOBECOM), 2015
    Co-Authors: Sungwoo Park, Robert C. Daniels, Robert W. Heath
    Abstract:

    Wireless Link Adaptation configures the physical layer of the transmitter in the presence of dynamic channel conditions to maximize Link performance under error rate reliability constraints. Typically, error rate reliability targets are defined externally and remain fixed, regardless of the physical layer configuration. In this paper, we allow Link Adaptation to define its own error rate reliability target.We derive a closed form expression for the optimal target block error rate (BLER) that maximizes the throughput with hybrid automatic repeat request (HARQ). This expression shows that the optimal BLER target is inversely proportional to the SINR. We conduct LTE simulations with Link Adaptation that exploits the optimal BLER target to reinforce the utility of our derived BLER target expression and to showcase that a performance improvements of up to 30% in throughput can be obtained through dynamic BLER targets for Link Adaptation.

  • optimizing the target error rate for Link Adaptation
    Global Communications Conference, 2014
    Co-Authors: Sungwoo Park, Robert C. Daniels, Robert W. Heath
    Abstract:

    Wireless Link Adaptation configures the physical layer of the transmitter in the presence of dynamic channel conditions to maximize Link performance under error rate reliability constraints. Typically, error rate reliability targets are defined externally and remain fixed, regardless of the physical layer configuration. In this paper, we allow Link Adaptation to define its own error rate reliability target.We derive a closed form expression for the optimal target block error rate (BLER) that maximizes the throughput with hybrid automatic repeat request (HARQ). This expression shows that the optimal BLER target is inversely proportional to the SINR. We conduct LTE simulations with Link Adaptation that exploits the optimal BLER target to reinforce the utility of our derived BLER target expression and to showcase that a performance improvements of up to 30% in throughput can be obtained through dynamic BLER targets for Link Adaptation.

  • Link Adaptation with position motion information in vehicle to vehicle networks
    IEEE Transactions on Wireless Communications, 2012
    Co-Authors: Robert C. Daniels, Robert W. Heath
    Abstract:

    Wireless communication networks use Link Adaptation to select physical layer parameters that optimize the transmission strategy as a function of the wireless channel realization. In the vehicle-to-vehicle (V2V) networks considered in this letter, the short coherence time of the wireless channel makes Link Adaptation based on the impulse response challenging. Consequently, Link Adaptation in V2V wireless networks may instead exploit the large-scale characteristics of the wireless channel (i.e. path loss) since they evolve slowly and enable less frequent feedback. Large-scale channel information may be captured through channel or position/motion measurements. We show, through the definition of new large-scale coherence expressions, that channel measurements render large-scale coherence as a function of time-change while the position/motion measurements render coherence as a function of velocity-change. This letter is concluded with highway simulations of modeled and measured channels to demonstrate the advantage of position/motion information for feedback reduction in V2V Link Adaptation.

  • Link Adaptation with Position/Motion Information in Vehicle-to-Vehicle Networks
    IEEE Transactions on Wireless Communications, 2012
    Co-Authors: Robert C. Daniels, Robert W. Heath
    Abstract:

    Wireless communication networks use Link Adaptation to select physical layer parameters that optimize the transmission strategy as a function of the wireless channel realization. In the vehicle-to-vehicle (V2V) networks considered in this letter, the short coherence time of the wireless channel makes Link Adaptation based on the impulse response challenging. Consequently, Link Adaptation in V2V wireless networks may instead exploit the large-scale characteristics of the wireless channel (i.e. path loss) since they evolve slowly and enable less frequent feedback. Large-scale channel information may be captured through channel or position/motion measurements. We show, through the definition of new large-scale coherence expressions, that channel measurements render large-scale coherence as a function of time-change while the position/motion measurements render coherence as a function of velocity-change. This letter is concluded with highway simulations of modeled and measured channels to demonstrate the advantage of position/motion information for feedback reduction in V2V Link Adaptation.

  • Distributed Link Adaptation for multicast traffic in MIMO-OFDM systems
    Physical Communication, 2011
    Co-Authors: Constantine Caramanis, Robert W. Heath
    Abstract:

    Abstract Multicast traffic exploits the broadcast nature of the wireless medium to deliver the same data to multiple users improving the bandwidth efficiency. Link Adaptation can be used in multicast transmission to further increase data rates exploiting feedback from the users. However, it is not easy to have the quality of service (QoS) of every intended receiver met while pushing the data rate to the Link capacity. Due to this difficulty, the conventional approach is to transmit isotropically with a fixed basic rate giving up the opportunity of increased throughput. For point-to-point unicast traffic, machine learning algorithms have recently found successful application in Link Adaptation due to their flexibility and ability to capture more environmental effects implicitly than classical Adaptation algorithms. In this paper, we propose a machine learning based distributed algorithm for Link Adaptation for multicast traffic in multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) systems. Our computations show that the data driven approach for Link Adaptation provides good prediction of the optimal modulation and coding scheme (MCS) outperforming the fixed MCS policies collectively. The distributed algorithm using dual decomposition reduces the required feedback amount significantly while maintaining the near-optimal throughput performance.

Robert C. Daniels - One of the best experts on this subject based on the ideXlab platform.

  • GLOBECOM - Optimizing the Target Error Rate for Link Adaptation
    2015 IEEE Global Communications Conference (GLOBECOM), 2015
    Co-Authors: Sungwoo Park, Robert C. Daniels, Robert W. Heath
    Abstract:

    Wireless Link Adaptation configures the physical layer of the transmitter in the presence of dynamic channel conditions to maximize Link performance under error rate reliability constraints. Typically, error rate reliability targets are defined externally and remain fixed, regardless of the physical layer configuration. In this paper, we allow Link Adaptation to define its own error rate reliability target.We derive a closed form expression for the optimal target block error rate (BLER) that maximizes the throughput with hybrid automatic repeat request (HARQ). This expression shows that the optimal BLER target is inversely proportional to the SINR. We conduct LTE simulations with Link Adaptation that exploits the optimal BLER target to reinforce the utility of our derived BLER target expression and to showcase that a performance improvements of up to 30% in throughput can be obtained through dynamic BLER targets for Link Adaptation.

  • optimizing the target error rate for Link Adaptation
    Global Communications Conference, 2014
    Co-Authors: Sungwoo Park, Robert C. Daniels, Robert W. Heath
    Abstract:

    Wireless Link Adaptation configures the physical layer of the transmitter in the presence of dynamic channel conditions to maximize Link performance under error rate reliability constraints. Typically, error rate reliability targets are defined externally and remain fixed, regardless of the physical layer configuration. In this paper, we allow Link Adaptation to define its own error rate reliability target.We derive a closed form expression for the optimal target block error rate (BLER) that maximizes the throughput with hybrid automatic repeat request (HARQ). This expression shows that the optimal BLER target is inversely proportional to the SINR. We conduct LTE simulations with Link Adaptation that exploits the optimal BLER target to reinforce the utility of our derived BLER target expression and to showcase that a performance improvements of up to 30% in throughput can be obtained through dynamic BLER targets for Link Adaptation.

  • Link Adaptation with position motion information in vehicle to vehicle networks
    IEEE Transactions on Wireless Communications, 2012
    Co-Authors: Robert C. Daniels, Robert W. Heath
    Abstract:

    Wireless communication networks use Link Adaptation to select physical layer parameters that optimize the transmission strategy as a function of the wireless channel realization. In the vehicle-to-vehicle (V2V) networks considered in this letter, the short coherence time of the wireless channel makes Link Adaptation based on the impulse response challenging. Consequently, Link Adaptation in V2V wireless networks may instead exploit the large-scale characteristics of the wireless channel (i.e. path loss) since they evolve slowly and enable less frequent feedback. Large-scale channel information may be captured through channel or position/motion measurements. We show, through the definition of new large-scale coherence expressions, that channel measurements render large-scale coherence as a function of time-change while the position/motion measurements render coherence as a function of velocity-change. This letter is concluded with highway simulations of modeled and measured channels to demonstrate the advantage of position/motion information for feedback reduction in V2V Link Adaptation.

  • Link Adaptation with Position/Motion Information in Vehicle-to-Vehicle Networks
    IEEE Transactions on Wireless Communications, 2012
    Co-Authors: Robert C. Daniels, Robert W. Heath
    Abstract:

    Wireless communication networks use Link Adaptation to select physical layer parameters that optimize the transmission strategy as a function of the wireless channel realization. In the vehicle-to-vehicle (V2V) networks considered in this letter, the short coherence time of the wireless channel makes Link Adaptation based on the impulse response challenging. Consequently, Link Adaptation in V2V wireless networks may instead exploit the large-scale characteristics of the wireless channel (i.e. path loss) since they evolve slowly and enable less frequent feedback. Large-scale channel information may be captured through channel or position/motion measurements. We show, through the definition of new large-scale coherence expressions, that channel measurements render large-scale coherence as a function of time-change while the position/motion measurements render coherence as a function of velocity-change. This letter is concluded with highway simulations of modeled and measured channels to demonstrate the advantage of position/motion information for feedback reduction in V2V Link Adaptation.

Huaiyu Dai - One of the best experts on this subject based on the ideXlab platform.

  • Joint antenna selection and Link Adaptation for MIMO systems
    IEEE Transactions on Vehicular Technology, 2006
    Co-Authors: Quan Zhou, Huaiyu Dai
    Abstract:

    Multi-input multi-output (MIMO) systems, with multiple antennas at both the transmitter and the receiver, are anticipated to be widely employed in future wireless networks due to their predicted tremendous system capacity. To protect the transmitted data against random channel impairment, it is desirable to consider Link Adaptation, such as rate Adaptation and power control, to improve the system performance and guarantee certain quality of service. Based on the observation that Link Adaptation and antenna selection problems are often coupled, we propose a joint antenna subset selection and Link Adaptation study for MIMO systems. After the formulation of the multidimensional joint optimization problem, the main contribution of this paper lies in the design of efficient algorithms approaching the optimal solution for both uncorrelated and correlated MIMO channels. Specifically, we propose one simplified antenna selection and Link Adaptation rule based on the expected optimal number of active antennas for uncorrelated MIMO with Rayleigh fading and one for correlated MIMO channels only based on the slowly varying channel correlation information. Our proposed algorithms are verified through numerical results, demonstrating significant gains over traditional MIMO signaling, while feasible for practical implementation.

  • Joint antenna selection and Link Adaptation for MIMO systems
    Vehicular Technology Conference, 2004. VTC2004-Fall. 2004 IEEE 60th, 2004
    Co-Authors: Quan Zhou, Huaiyu Dai
    Abstract:

    Based on the observation that Link Adaptation and antenna selection problems are often coupled, this paper studies the problem of joint antenna subset selection and Link Adaptation for MIMO systems. After the formulation of the multidimensional joint optimization problem, the main contribution of this paper lies in the design of efficient algorithms approaching the optimal solution for both uncorrelated and correlated MIMO channels. Specifically, we propose one simplified antenna selection and Link Adaptation rule based on the expected optimal number of active antennas for uncorrelated MIMO with Raleigh fading, and one for correlated MIMO channels only based on the slowly varying channel correlation information. Our proposed algorithms are verified through numerical results, demonstrating significant gains over traditional MIMO signaling while feasible for practical implementation.

John Dunlop - One of the best experts on this subject based on the ideXlab platform.

  • Performance and configuration of Link Adaptation algorithms with mobile speed
    2012
    Co-Authors: Javier Gozalvez, John Dunlop
    Abstract:

    Link Adaptation is an adaptive radio Link technique that selects a transport mode, from a set of predefined modes of varying robustness, depending on the channel quality conditions and dynamics. Previous work has shown the need to adapt the configuration of the Link Adaptation algorithm to certain operating conditions such as the system load. Since the channel quality dynamics are also influenced by the user speed, this paper investigates the impact of the mobile speed on the performance and configuration of Link Adaptation algorithms

  • System performance and adaptive configuration of Link Adaptation techniques in packet-switched cellular radio networks
    Computer Networks, 2005
    Co-Authors: Javier Gozalvez, John Dunlop
    Abstract:

    Link Adaptation is an adaptive radio resource management technique that selects a transport mode from a set of predefined modes of varying robustness, depending on the experienced channel quality conditions and dynamics. Previous work has shown the need to adapt the configuration of Link Adaptation to certain operating conditions affecting the channel quality dynamics. In particular, it was shown that the system load can considerably influence the performance and configuration of Link Adaptation techniques. The user mobile speed is another key factor influencing the channel quality dynamics. As a result, the aim of this paper is to investigate whether the user mobile speed should also be taken into account when configuring and designing the operation of Link Adaptation techniques.

  • On the Dynamics of Link Adaptation Updating Periods for Packet Switched Systems
    Wireless Personal Communications, 2002
    Co-Authors: Javier Gozalvez, John Dunlop
    Abstract:

    Link Adaptation is an adaptive radio Link technique that selects a transport mode, from a set of predefined modes of varying robustness, depending on the channel quality. One of the parameters that has to be defined when considering the application of Link Adaptation is the updating period which indicates how often a decision is made on the transport mode to use. This paper analyses the Link Adaptation performance for various updating periods under different operating conditions affecting the channel quality dynamics.

  • GPRS Link Adaptation switching thresholds and intervals
    Electronics Letters, 2000
    Co-Authors: Javier Gozalvez, John Dunlop
    Abstract:

    A complementary approach is presented for obtaining the Link Adaptation (LA) switching thresholds defining the regions (CIR ranges) where each coding scheme is most suitable. The approach is based on multiple replications providing an indication of the accuracy of the threshold. GPRS (General Packet Radio Services) and different operating environments are studied.

  • Link Adaptation in ATDMA
    Electronics Letters, 1995
    Co-Authors: John Dunlop, James Irvine, P. Cosimini
    Abstract:

    The Letter considers the potential of Link Adaptation, which has been examined within the RACE ATDMA project, for improving spectral efficiency. Net rate Adaptation for voice services and the influence of some of the practical constraints on system performance are investigated.

Quan Zhou - One of the best experts on this subject based on the ideXlab platform.

  • Joint antenna selection and Link Adaptation for MIMO systems
    IEEE Transactions on Vehicular Technology, 2006
    Co-Authors: Quan Zhou, Huaiyu Dai
    Abstract:

    Multi-input multi-output (MIMO) systems, with multiple antennas at both the transmitter and the receiver, are anticipated to be widely employed in future wireless networks due to their predicted tremendous system capacity. To protect the transmitted data against random channel impairment, it is desirable to consider Link Adaptation, such as rate Adaptation and power control, to improve the system performance and guarantee certain quality of service. Based on the observation that Link Adaptation and antenna selection problems are often coupled, we propose a joint antenna subset selection and Link Adaptation study for MIMO systems. After the formulation of the multidimensional joint optimization problem, the main contribution of this paper lies in the design of efficient algorithms approaching the optimal solution for both uncorrelated and correlated MIMO channels. Specifically, we propose one simplified antenna selection and Link Adaptation rule based on the expected optimal number of active antennas for uncorrelated MIMO with Rayleigh fading and one for correlated MIMO channels only based on the slowly varying channel correlation information. Our proposed algorithms are verified through numerical results, demonstrating significant gains over traditional MIMO signaling, while feasible for practical implementation.

  • Joint antenna selection and Link Adaptation for MIMO systems
    Vehicular Technology Conference, 2004. VTC2004-Fall. 2004 IEEE 60th, 2004
    Co-Authors: Quan Zhou, Huaiyu Dai
    Abstract:

    Based on the observation that Link Adaptation and antenna selection problems are often coupled, this paper studies the problem of joint antenna subset selection and Link Adaptation for MIMO systems. After the formulation of the multidimensional joint optimization problem, the main contribution of this paper lies in the design of efficient algorithms approaching the optimal solution for both uncorrelated and correlated MIMO channels. Specifically, we propose one simplified antenna selection and Link Adaptation rule based on the expected optimal number of active antennas for uncorrelated MIMO with Raleigh fading, and one for correlated MIMO channels only based on the slowly varying channel correlation information. Our proposed algorithms are verified through numerical results, demonstrating significant gains over traditional MIMO signaling while feasible for practical implementation.