The Experts below are selected from a list of 100524 Experts worldwide ranked by ideXlab platform

Timo Koskela - One of the best experts on this subject based on the ideXlab platform.

  • Device-to-device (D2D) Communication in cellular network - Performance analysis of optimum and practical Communication Mode selection
    IEEE Wireless Communications and Networking Conference WCNC, 2010
    Co-Authors: Sami Hakola, Janne Lehtoma, Tao Chen, Timo Koskela
    Abstract:

    In a cellular network system one way to increase its capacity is to allow direct Communication between closely located user devices when they are communicating with each other instead of conveying data from one device to the other via the radio and core network. The problem is then when the network shall assign direct Communication Mode and when not. In previous works the decision has been done individually per communicating device pair not taking into account other devices and the current state of the network. We derive means for getting optimal Communication Mode for all devices in the system in terms of system equations. The system equations capture information of the network such as link gains, noise levels, signal-to-interference-and-noise-ratios, etc., as well as Communication Mode selection for the devices. Using the derived equations performance bounds for the cellular system where D2D Communication is an additional Communication Mode are illustrated via simulations. Further, practical Communication Mode selection algorithms are used to evaluate their system performance against the achievable bounds. Analysis show the usability of the system equations and the potential of having D2D operation integrated into a cellular system when there is enough local Communication occurring.

Shi Weihang - One of the best experts on this subject based on the ideXlab platform.

  • simulation research of wireless sensor networks based on leach protocol
    Computer Simulation, 2011
    Co-Authors: Shi Weihang
    Abstract:

    Study about wireless sensor routing algorithms.The energy supply of nodes will be limited strictly in the wireless sensor networks(WSN).An improved LEACH routing clustering algorithm(I_LEACH) is proposed.In the choice stage,the algorithm of cluster considers the factors of energy,and the threshold LEACH algorithm was improved to prevent the nodes become low energy of cluster nodes.In the cluster data transmission stage,and the combination Communication Mode of multi-jump and single-jump was used,which changed the traditional single node energy Communication Mode,balanced the energy,and avoided the problem that the energy of the node far from base exhausted early.Finally simulation experiment is conducted in Matlab.The simulation results show that,compared with the traditional algorithm,I_LEACH LEACH algorithm can balance the nodes of cluster and energy consumption and prolong the life time of network.

Sami Hakola - One of the best experts on this subject based on the ideXlab platform.

  • Device-to-device (D2D) Communication in cellular network - Performance analysis of optimum and practical Communication Mode selection
    IEEE Wireless Communications and Networking Conference WCNC, 2010
    Co-Authors: Sami Hakola, Janne Lehtoma, Tao Chen, Timo Koskela
    Abstract:

    In a cellular network system one way to increase its capacity is to allow direct Communication between closely located user devices when they are communicating with each other instead of conveying data from one device to the other via the radio and core network. The problem is then when the network shall assign direct Communication Mode and when not. In previous works the decision has been done individually per communicating device pair not taking into account other devices and the current state of the network. We derive means for getting optimal Communication Mode for all devices in the system in terms of system equations. The system equations capture information of the network such as link gains, noise levels, signal-to-interference-and-noise-ratios, etc., as well as Communication Mode selection for the devices. Using the derived equations performance bounds for the cellular system where D2D Communication is an additional Communication Mode are illustrated via simulations. Further, practical Communication Mode selection algorithms are used to evaluate their system performance against the achievable bounds. Analysis show the usability of the system equations and the potential of having D2D operation integrated into a cellular system when there is enough local Communication occurring.

Qin Yingli - One of the best experts on this subject based on the ideXlab platform.

Nobuo Goto - One of the best experts on this subject based on the ideXlab platform.

  • adaptive compensation for the angular deflection of beams carrying orbital angular momentum on Mode sorting
    Japanese Journal of Applied Physics, 2019
    Co-Authors: Hiroki Kishikawa, Noriyuki Sakashita, Nobuo Goto
    Abstract:

    Beams carrying orbital angular momentum (OAM) has attracted attention as a potential candidate to expand the transmission capacity in the optical Communication. Mode sorting is an efficient method to demultiplex the OAM multiplexed lightwaves. We have reported the Mode sorting performance for OAM beams suffering lateral displacement and angular deflection. It was found that the angular deflection was severe, namely, only 100-μrad deflection deteriorated the performance in terms of crosstalk. Thus, the strict angular alignment would be required in the free-space optical Communication using OAM multiplexing. In this paper, we propose an adaptive compensation method based on detection of the angular deflection of beams carrying OAM on Mode sorting in order to relax such a strict requirement. Numerical simulation results reveal that the compensation in every 100 μrad effectively suppresses the crosstalk caused by the angular deflection.

  • Mode sorting performance for optical beams carrying orbital angular momentum suffering lateral displacement and angular deflection
    Japanese Journal of Applied Physics, 2018
    Co-Authors: Hiroki Kishikawa, Noriyuki Sakashita, Nobuo Goto
    Abstract:

    Beams carrying orbital angular momentum (OAM) is expected to be a new degree of multiplexing to increase transmission capacity in the optical Communication. Mode sorting methods have been reported so far as efficient ways to demultiplex such OAM multiplexed lightwaves. Since the OAM transmission is mainly through free-space, the transmitting OAM lightwave may suffer lateral displacement and angular deflection on the receiver plane. In this paper, we numerically investigate the tolerance to lateral displacement and angular deflection on the Mode sorting performances for beams carrying OAM. Comparing the performance in terms of crosstalk in between high resolution and ordinary resolution Mode sorting methods reveals that the high resolution one shows a slight lower crosstalk while almost the same tolerance as the ordinary resolution one.