The Experts below are selected from a list of 288312 Experts worldwide ranked by ideXlab platform

Raghupathy Sivakumar - One of the best experts on this subject based on the ideXlab platform.

  • a transport Layer Approach for achieving aggregate bandwidths on multi homed mobile hosts
    Wireless Networks, 2005
    Co-Authors: Hungyun Hsieh, Raghupathy Sivakumar
    Abstract:

    Due to the availability of a wide variety of wireless access technologies, a mobile host can potentially have subscriptions and access to more than one wireless network at a given time. In this paper, we consider such a multi-homed mobile host, and address the problem of achieving bandwidth aggregation by striping data across the multiple interfaces of the mobile host. We show that both link Layer striping Approaches and application Layer techniques that stripe data across multiple TCP sockets, do not achieve optimal bandwidth aggregation due to a variety of factors specific to wireless networks. We propose an end-to-end transport Layer Approach called pTCP that effectively performs bandwidth aggregation on multi-homed mobile hosts. We show through simulations that pTCP achieves the desired goals under a variety of network conditions.

  • a transport Layer Approach for achieving aggregate bandwidths on multi homed mobile hosts
    ACM IEEE International Conference on Mobile Computing and Networking, 2002
    Co-Authors: Hungyun Hsieh, Raghupathy Sivakumar
    Abstract:

    Due to the availability of a wide variety of wireless access technologies, a mobile host can potentially have subscriptions and access to more than one wireless network at a given time. In this paper, we consider such a multi-homed mobile host, and address the problem of achieving bandwidth aggregation by striping data across the multiple interfaces of the mobile host. We show that both link Layer striping Approaches and application Layer techniques that stripe data across multiple TCP sockets do not achieve the optimal bandwidth aggregation due to a variety of factors specific to wireless networks. We propose an end-to-end transport Layer Approach called pTCP that effectively performs bandwidth aggregation on multi homed mobile hosts. We show through simulations that pTCP achieves the desired goals under a variety of network conditions.

Hüseyi Arsla - One of the best experts on this subject based on the ideXlab platform.

  • Inter-Numerology Interference Management With Adaptive Guards: A Cross-Layer Approach
    IEEE Access, 2020
    Co-Authors: Ali Fatih Demi, Hüseyi Arsla
    Abstract:

    The next-generation communication technologies are evolving towards increased flexibility in various aspects. Although orthogonal frequency division multiplexing (OFDM) remains as the waveform of the upcoming fifth-generation (5G) standard, the new radio provides flexibility in waveform parametrization (a.k.a. numerology) to address diverse requirements. However, managing the peaceful coexistence of mixed numerologies is challenging due to inter-numerology interference (INI). This paper proposes the utilization of adaptive guards in both time and frequency domains as a solution along with a multi-window operation in the physical (PHY) Layer. The adaptive windowing operation needs a guard duration to reduce the unwanted emissions, and a guard band is required to handle the INI level on the adjacent band. The guards in both domains are jointly optimized with respect to the subcarrier spacing, use case (i.e., service requirement), and power offset between the numerologies. Also, the multi-window Approach provides managing each side of the spectrum independently in case of an asymmetric interference scenario. Since the allowed interference level depends on the numerologies operating in the adjacent bands, the potential of adaptive guards is further increased and exploited with a medium access control (MAC) Layer scheduling technique. The proposed INI-based scheduling algorithm decreases the need for guards by allocating the numerologies to the available bands, considering their subcarrier spacing, power level, and SIR requirements. Therefore, INI management is performed with a cross-Layer (PHY and MAC) Approach in this study. The results show that the precise design that accommodates such flexibility reduces the guards significantly and improves the spectral efficiency of mixed numerology systems.

Hungyun Hsieh - One of the best experts on this subject based on the ideXlab platform.

  • a transport Layer Approach for achieving aggregate bandwidths on multi homed mobile hosts
    Wireless Networks, 2005
    Co-Authors: Hungyun Hsieh, Raghupathy Sivakumar
    Abstract:

    Due to the availability of a wide variety of wireless access technologies, a mobile host can potentially have subscriptions and access to more than one wireless network at a given time. In this paper, we consider such a multi-homed mobile host, and address the problem of achieving bandwidth aggregation by striping data across the multiple interfaces of the mobile host. We show that both link Layer striping Approaches and application Layer techniques that stripe data across multiple TCP sockets, do not achieve optimal bandwidth aggregation due to a variety of factors specific to wireless networks. We propose an end-to-end transport Layer Approach called pTCP that effectively performs bandwidth aggregation on multi-homed mobile hosts. We show through simulations that pTCP achieves the desired goals under a variety of network conditions.

  • a transport Layer Approach for achieving aggregate bandwidths on multi homed mobile hosts
    ACM IEEE International Conference on Mobile Computing and Networking, 2002
    Co-Authors: Hungyun Hsieh, Raghupathy Sivakumar
    Abstract:

    Due to the availability of a wide variety of wireless access technologies, a mobile host can potentially have subscriptions and access to more than one wireless network at a given time. In this paper, we consider such a multi-homed mobile host, and address the problem of achieving bandwidth aggregation by striping data across the multiple interfaces of the mobile host. We show that both link Layer striping Approaches and application Layer techniques that stripe data across multiple TCP sockets do not achieve the optimal bandwidth aggregation due to a variety of factors specific to wireless networks. We propose an end-to-end transport Layer Approach called pTCP that effectively performs bandwidth aggregation on multi homed mobile hosts. We show through simulations that pTCP achieves the desired goals under a variety of network conditions.

Ali Fatih Demi - One of the best experts on this subject based on the ideXlab platform.

  • Inter-Numerology Interference Management With Adaptive Guards: A Cross-Layer Approach
    IEEE Access, 2020
    Co-Authors: Ali Fatih Demi, Hüseyi Arsla
    Abstract:

    The next-generation communication technologies are evolving towards increased flexibility in various aspects. Although orthogonal frequency division multiplexing (OFDM) remains as the waveform of the upcoming fifth-generation (5G) standard, the new radio provides flexibility in waveform parametrization (a.k.a. numerology) to address diverse requirements. However, managing the peaceful coexistence of mixed numerologies is challenging due to inter-numerology interference (INI). This paper proposes the utilization of adaptive guards in both time and frequency domains as a solution along with a multi-window operation in the physical (PHY) Layer. The adaptive windowing operation needs a guard duration to reduce the unwanted emissions, and a guard band is required to handle the INI level on the adjacent band. The guards in both domains are jointly optimized with respect to the subcarrier spacing, use case (i.e., service requirement), and power offset between the numerologies. Also, the multi-window Approach provides managing each side of the spectrum independently in case of an asymmetric interference scenario. Since the allowed interference level depends on the numerologies operating in the adjacent bands, the potential of adaptive guards is further increased and exploited with a medium access control (MAC) Layer scheduling technique. The proposed INI-based scheduling algorithm decreases the need for guards by allocating the numerologies to the available bands, considering their subcarrier spacing, power level, and SIR requirements. Therefore, INI management is performed with a cross-Layer (PHY and MAC) Approach in this study. The results show that the precise design that accommodates such flexibility reduces the guards significantly and improves the spectral efficiency of mixed numerology systems.

Jianhui Hou - One of the best experts on this subject based on the ideXlab platform.

  • toward efficient polymer solar cells processed by a solution processed Layer by Layer Approach
    Advanced Materials, 2018
    Co-Authors: Yong Cui, Shaoqing Zhang, Ningning Liang, Jingyi Kong, Chenyi Yang, Huifeng Yao, Jianhui Hou
    Abstract:

    The solution-processed Layer-by-Layer (LBL) method has potential to achieve high-performance polymer solar cells (PSCs) due to its advantage of enriching donors near the anode and acceptors near the cathode. However, power conversion efficiencies (PCEs) of the LBL-PSCs are still significantly lower than those of conventional one-step-processed PSCs (OS-PSCs). A method to solve the critical problems in LBL-PSCs is reported here. By employing a specific mixed solvent (o-dichlorobenzene [o-DCB]/tetrahydrofuran) to spin-coat the small-molecular acceptor IT-4F onto a Layer of the newly designed polymer donor (PBDB-TFS1), appropriate interdiffusion between the PBDB-TFS1 and the IT-4F can critically be controlled, and then an ideal phase separation of the active Layer and large donor/acceptor interface area can be realized with a certain amount of o-DCB. The PSCs based on the LBL method exhibit PCEs as high as 13.0%, higher than that of the counterpart (11.8%) made by the conventional OS solution method. This preliminary work reveals that the LBL method is a promising Approach to the promotion of the photovoltaic performance of polymer solar cells.