The Experts below are selected from a list of 57639 Experts worldwide ranked by ideXlab platform

Choong-ho Cho - One of the best experts on this subject based on the ideXlab platform.

  • Downlink packet scheduling based on Channel Condition for multimedia services of mobile users in OFDMA-TDD
    Lecture Notes in Computer Science, 2005
    Co-Authors: Se-jin Kim, Hyong-woo Lee, Choong-ho Cho
    Abstract:

    In this paper, we propose a Wireless Class Based Flexible Queueing (WCBFQ) which is an improved packet scheduling with QoS management based on wireless networks using OFDMA-TDD with adaptive modulation. Under time-varying Channel Condition, scheduler tries to guarantee required throughput demand for real-time traffic by allocating more Channel time to the users in poor Channel Condition. On the other hand, for non-real time traffic, the scheduler gives lower priority to those experiencing poor Channel Conditions thereby favoring those having better Channel for increased overall system throughput. Simulations are performed to demonstrate the effectiveness of the proposed scheme.

  • PCM (2) - Downlink packet scheduling based on Channel Condition for multimedia services of mobile users in OFDMA-TDD
    Advances in Multimedia Information Processing - PCM 2005, 2005
    Co-Authors: Se-jin Kim, Hyong-woo Lee, Choong-ho Cho
    Abstract:

    In this paper, we propose a Wireless Class Based Flexible Queueing (WCBFQ) which is an improved packet scheduling with QoS management based on wireless networks using OFDMA-TDD with adaptive modulation. Under time-varying Channel Condition, scheduler tries to guarantee required throughput demand for real-time traffic by allocating more Channel time to the users in poor Channel Condition. On the other hand, for non-real time traffic, the scheduler gives lower priority to those experiencing poor Channel Conditions thereby favoring those having better Channel for increased overall system throughput. Simulations are performed to demonstrate the effectiveness of the proposed scheme.

Hsiao-hwa Chen - One of the best experts on this subject based on the ideXlab platform.

  • sliced spectrum sensing a Channel Condition aware sensing technique for cognitive radio networks
    IEEE Transactions on Vehicular Technology, 2018
    Co-Authors: Mengying Zhang, Hsiao-hwa Chen
    Abstract:

    Cognitive radio technology, which helps to alleviate spectrum scarcity problem, plays an important role in future wireless communication systems. Spectrum sensing is the key technique of cognitive radio. The upcoming fifth generation (5G) communications need to deal with fast time-varying Channels (i.e., Channel state is non-static within a sensing window), while existing sensing methods are based mainly on conventional quasi-static Channels. Consequently, traditional sensing methods may not work well in 5G communications. This paper aims to propose a sliced sensing technique, which can support 5G cognitive radio applications working in fast time-varying Channels. We analyze the impact of non-static Channels on the performance of traditional sensing methods and disclose a negative factor, i.e., out-of-phase feature distortion effect. Accordingly, we propose a sliced spectrum sensing scheme and probe its feasibility via several relevant trials. Based on the aforementioned works, a complete version of the sliced sensing technique is designed, which can adapt to Channel variation and choose the optimal slicing strategy. Simulation results manifest that the sliced sensing technique outperforms traditional sensing methods in both Rayleigh fading and 3GPP spatial Channel models.

  • Channel Condition Aware Detection in Statistical Signal Transmission
    IEEE Transactions on Wireless Communications, 2017
    Co-Authors: Mengying Zhang, Sha Yao, Hsiao-hwa Chen
    Abstract:

    Heterogeneous network (HetNet) plays an important role in the upcoming 5G communications. A HetNet in futuristic communications is envisaged to provide full access data services, such that users will always have the best service with their available radio resources. To realize a full access HetNet, statistical signal transmission (SST) can be an important enabling technique. SST exploits statistical features of ordinary signals as a data transmission scheme to carry information data. Due to its inherent unique properties, SST signal is more robust than ordinary signals in conventional quasi-static Channels. However, detection of SST signals in fast time-varying Channels will face challenges. Motivated by this fact, this paper aims to analyze the impact of fast time-varying Channels to SST, and reveals negative effects of burst of deep fading Channel-state (BDFC) and feature dissipation with out-of-phase (FDOP). Accordingly, we design an automatic re-transmission scheme and a fragmental feature capturing method to mitigate the aforementioned issues, respectively. Based on these studies, we propose a Channel Condition aware detection scheme for SST, aiming to enhance SST detection performance in fast time-varying Channels. Numerical results show that with the proposed scheme, a maximum gain of more than 10 dB can be obtained under either BDFC or FDOP Condition. Furthermore, it is also demonstrated that the proposed scheme is robust with imperfect Channel coherence time information, which is attractive for practical applications.

Se-jin Kim - One of the best experts on this subject based on the ideXlab platform.

  • Downlink packet scheduling based on Channel Condition for multimedia services of mobile users in OFDMA-TDD
    Lecture Notes in Computer Science, 2005
    Co-Authors: Se-jin Kim, Hyong-woo Lee, Choong-ho Cho
    Abstract:

    In this paper, we propose a Wireless Class Based Flexible Queueing (WCBFQ) which is an improved packet scheduling with QoS management based on wireless networks using OFDMA-TDD with adaptive modulation. Under time-varying Channel Condition, scheduler tries to guarantee required throughput demand for real-time traffic by allocating more Channel time to the users in poor Channel Condition. On the other hand, for non-real time traffic, the scheduler gives lower priority to those experiencing poor Channel Conditions thereby favoring those having better Channel for increased overall system throughput. Simulations are performed to demonstrate the effectiveness of the proposed scheme.

  • PCM (2) - Downlink packet scheduling based on Channel Condition for multimedia services of mobile users in OFDMA-TDD
    Advances in Multimedia Information Processing - PCM 2005, 2005
    Co-Authors: Se-jin Kim, Hyong-woo Lee, Choong-ho Cho
    Abstract:

    In this paper, we propose a Wireless Class Based Flexible Queueing (WCBFQ) which is an improved packet scheduling with QoS management based on wireless networks using OFDMA-TDD with adaptive modulation. Under time-varying Channel Condition, scheduler tries to guarantee required throughput demand for real-time traffic by allocating more Channel time to the users in poor Channel Condition. On the other hand, for non-real time traffic, the scheduler gives lower priority to those experiencing poor Channel Conditions thereby favoring those having better Channel for increased overall system throughput. Simulations are performed to demonstrate the effectiveness of the proposed scheme.

Dayo Huang - One of the best experts on this subject based on the ideXlab platform.

  • a secant location estimation scheme in error prone Channel Condition for wireless sensor networks
    International Conference on High Performance Computing and Simulation, 2013
    Co-Authors: Tsunghan Lee, Linhuang Chang, Kuohsun Hsu, Dayo Huang
    Abstract:

    Location-based service is one of important application for Wireless Sensor Networks (WSN). Most location information mainly depends on the Receiver Signal Strength (RSS) to estimate the distance between the reference node and the location unknown node. However, the multipath fading and co-Channel interference in 2.4GHz ISM-band will affect the accuracy of the position estimation in wireless sensor networks. In this paper, the effect of distance error in error-prone Channel Condition has been investigated. A secant Location Estimation Scheme (SLES) is proposed to improve the accuracy of the position estimation in error-prone Channel Condition. The simulation results show the proposed algorithm is accurate and effective.

  • HPCS - A secant location estimation scheme in error-prone Channel Condition for wireless sensor networks
    2013 International Conference on High Performance Computing & Simulation (HPCS), 2013
    Co-Authors: Tsunghan Lee, Linhuang Chang, Kuohsun Hsu, Dayo Huang
    Abstract:

    Location-based service is one of important application for Wireless Sensor Networks (WSN). Most location information mainly depends on the Receiver Signal Strength (RSS) to estimate the distance between the reference node and the location unknown node. However, the multipath fading and co-Channel interference in 2.4GHz ISM-band will affect the accuracy of the position estimation in wireless sensor networks. In this paper, the effect of distance error in error-prone Channel Condition has been investigated. A secant Location Estimation Scheme (SLES) is proposed to improve the accuracy of the position estimation in error-prone Channel Condition. The simulation results show the proposed algorithm is accurate and effective.

Jeffrey H. Reed - One of the best experts on this subject based on the ideXlab platform.

  • GLOBECOM - The Impact of Channel Variations on Wireless Distributed Computing Networks
    GLOBECOM 2009 - 2009 IEEE Global Telecommunications Conference, 2009
    Co-Authors: Xuetao Chen, Timothy R. Newman, Dinesh Datla, Tamal Bose, Jeffrey H. Reed
    Abstract:

    Wireless distributed computing has several unique problems compared with currently well investigated wireless sensor networks. These problems include the impact of Channel variation on power allocation, different traffic pattern with higher utilization, and more restricted delay constraints. This paper investigates the impact of communication Channel Condition on the average execution time of the computing task within wireless distributed computing networks (WDCN). It has been found that the delay performance of wireless distributed computing is influenced by both the average Channel Condition and the variation of Channels. In addition, the impact of Channel heterogeneity is also investigated to show the possibility of the optimal workload distribution for energy saving and robustness. Finally, a workload distribution approach combined with a power allocation scheme exploiting the spatial heterogeneity of the Channel Condition is proposed to balance energy efficiency and robustness.

  • Sub-band beamforming for OFDM system in practical Channel Condition
    IEEE 60th Vehicular Technology Conference 2004. VTC2004-Fall. 2004, 1
    Co-Authors: Fakhrul Alam, B.l.p. Cheung, Raqibul Mostafa, W.g. Newhall, Brian D. Woerner, Jeffrey H. Reed
    Abstract:

    Orthogonal frequency division multiplexing (OFDM) is a multi-carrier technique that has recently received considerable attention for high speed wireless communication and ad hoc networks. In this paper we develop a simple pilot symbol assisted frequency domain beamforming technique for the OFDM receiver. The weight vector estimated with the proposed scheme cancels strong interference and minimizes Channel impairments. We investigate different aspects of the beamforming technique in a simple AWGN environment. The performance of the proposed beamforming scheme is demonstrated for a vector Channel based on actual measurement data. The applicability of computationally simple least mean square (LMS) algorithm instead of the recursive least square (RLS) algorithm is also investigated in this paper.