The Experts below are selected from a list of 117 Experts worldwide ranked by ideXlab platform

Daniel Larsson - One of the best experts on this subject based on the ideXlab platform.

  • design and evaluation of licensed assisted access lte in unlicensed spectrum
    IEEE Wireless Communications, 2016
    Co-Authors: Laetitia Falconetti, Amitav Mukherjee, Jungfu Cheng, Sorour Falahati, Du Ho Kang, Havish Koorapaty, Reem Karaki, Evanny Obregon, Daniel Larsson
    Abstract:

    Licensed assisted access (LAA) is a new feature for 3GPP LTE systems to operate in the unlicensed spectrum. Under LAA, licensed carriers will be aggregated with unlicensed carriers in order to opportunistically enhance user throughput, while still offering seamless mobility and outdoor coverage. In order to coexist with other technologies in the unlicensed bands, several new functionalities for LAA LTE have been introduced, including longterm channel selection, short-term channel sensing based on listen-before-talk (LBT), and Discontinuous Transmission on a carrier with limited maximum Transmission duration. In this article, we present research findings behind the designs for LAA systems. We discuss the impact of several parameters of the LAA LBT framework on the channel access opportunities of LAA, and its coexistence performance toward co-channel networks based on extensive system-level simulation results. The investigation covers both single-channel as well as multi-channel operation and coexistence scenarios. In addition to the finalized designs for downlink LAA operations in Release 13, our findings in this article further shed light on the uplink LAA operations to be introduced in Release 14.

  • licensed assisted access lte coexistence with ieee 802 11 and the evolution toward 5g
    IEEE Communications Magazine, 2016
    Co-Authors: Amitav Mukherjee, Jungfu Cheng, Sorour Falahati, Laetitia Falconetti, Du Ho Kang, Havish Koorapaty, Reem Karaki, Daniel Larsson
    Abstract:

    LAA is a new operation mode of LTE in the unlicensed spectrum, which will be featured in LTE Release 13. Under LAA, licensed carriers will be aggregated with unlicensed carriers in order to opportunistically enhance downlink user throughput while still offering seamless mobility support. In order to coexist with WiFi, some of the new functionalities required of LAA LTE include a mechanism for channel sensing based on listen-before-talk, Discontinuous Transmission on a carrier with limited maximum Transmission duration, and multicarrier Transmission across multiple unlicensed channels. This article presents a detailed overview of the design agreements for LAA, the impact of unlicensed spectrum operation on the LTE physical layer architecture, and the scope of additional enhancements beyond LTE Release 13. A range of simulations for indoor and multicarrier scenarios show that fair coexistence between LAA and WiFi can be achieved, and that deployment of LAA can provide a boost in WiFi performance.

  • system architecture and coexistence evaluation of licensed assisted access lte with ieee 802 11
    International Conference on Communications, 2015
    Co-Authors: Amitav Mukherjee, Jungfu Cheng, Sorour Falahati, Laetitia Falconetti, Anders Furuskar, Bruhtesfa Godana, Du Ho Kang, Havish Koorapaty, Daniel Larsson, Yu Yang
    Abstract:

    Licensed-assisted access (LAA) is a new operation mode of Long-Term Evolution (LTE) in the unlicensed spectrum currently under study in the 3GPP standardization forum. In order to coexist with Wi-Fi, some of the new functionalities required of LAA LTE include a mechanism for clear channel assessment based on listen-before-talk (LBT), Discontinuous Transmission on a carrier with limited maximum Transmission duration, and dynamic frequency selection (DFS) for radar avoidance in certain frequency bands. This paper presents a detailed overview of the impact of unlicensed spectrum operation on the LTE physical layer architecture, such as downlink physical channel design, scheduling, and radio resource management. System-level simulation results are then presented for indoor and outdoor scenarios, and show that fair coexistence between LAA and Wi-Fi can be achieved and that deployment of LAA can provide a boost in Wi-Fi performance.

Anna Rozanova-pierrat - One of the best experts on this subject based on the ideXlab platform.

  • Short-time heat diffusion in compact domains with Discontinuous Transmission boundary conditions
    Mathematical Models and Methods in Applied Sciences, 2015
    Co-Authors: Claude Bardos, Denis S. Grebenkov, Anna Rozanova-pierrat
    Abstract:

    We consider a heat problem with Discontinuous diffusion coefficients and Discontinuous Transmission boundary conditions with a resistance coefficient. For all bounded (ϵ, δ)-domains Ω ⊂ ℝn with a d-set boundary (for instance, a self-similar fractal), we find the first term of the small-time asymptotic expansion of the heat content in the complement of Ω, and also the second-order term in the case of a regular boundary. The asymptotic expansion is different for the cases of finite and infinite resistance of the boundary. The derived formulas relate the heat content to the volume of the interior Minkowski sausage and present a mathematical justification to the de Gennes' approach. The accuracy of the analytical results is illustrated by solving the heat problem on prefractal domains by a finite elements method.

  • Short time heat diffusion in compact domains with Discontinuous Transmission boundary conditions
    arXiv: Analysis of PDEs, 2015
    Co-Authors: Claude Bardos, Denis S. Grebenkov, Anna Rozanova-pierrat
    Abstract:

    We consider a heat problem with Discontinuous diffusion coefficientsand Discontinuous Transmission boundary conditions with a resistancecoefficient. For all compact $(\epsilon,\delta)$-domains $\Omega\subset\mathbb{R}^n$ with a $d$-set boundary (for instance, aself-similar fractal), we find the first term of the small-timeasymptotic expansion of the heat content in the complement of$\Omega$, and also the second-order term in the case of a regularboundary. The asymptotic expansion is different for the cases offinite and infinite resistance of the boundary. The derived formulasrelate the heat content to the volume of the interior Minkowskisausage and present a mathematical justification to the de Gennes'approach. The accuracy of the analytical results is illustrated bysolving the heat problem on prefractal domains by a finite elementsmethod.

Amitav Mukherjee - One of the best experts on this subject based on the ideXlab platform.

  • design and evaluation of licensed assisted access lte in unlicensed spectrum
    IEEE Wireless Communications, 2016
    Co-Authors: Laetitia Falconetti, Amitav Mukherjee, Jungfu Cheng, Sorour Falahati, Du Ho Kang, Havish Koorapaty, Reem Karaki, Evanny Obregon, Daniel Larsson
    Abstract:

    Licensed assisted access (LAA) is a new feature for 3GPP LTE systems to operate in the unlicensed spectrum. Under LAA, licensed carriers will be aggregated with unlicensed carriers in order to opportunistically enhance user throughput, while still offering seamless mobility and outdoor coverage. In order to coexist with other technologies in the unlicensed bands, several new functionalities for LAA LTE have been introduced, including longterm channel selection, short-term channel sensing based on listen-before-talk (LBT), and Discontinuous Transmission on a carrier with limited maximum Transmission duration. In this article, we present research findings behind the designs for LAA systems. We discuss the impact of several parameters of the LAA LBT framework on the channel access opportunities of LAA, and its coexistence performance toward co-channel networks based on extensive system-level simulation results. The investigation covers both single-channel as well as multi-channel operation and coexistence scenarios. In addition to the finalized designs for downlink LAA operations in Release 13, our findings in this article further shed light on the uplink LAA operations to be introduced in Release 14.

  • licensed assisted access lte coexistence with ieee 802 11 and the evolution toward 5g
    IEEE Communications Magazine, 2016
    Co-Authors: Amitav Mukherjee, Jungfu Cheng, Sorour Falahati, Laetitia Falconetti, Du Ho Kang, Havish Koorapaty, Reem Karaki, Daniel Larsson
    Abstract:

    LAA is a new operation mode of LTE in the unlicensed spectrum, which will be featured in LTE Release 13. Under LAA, licensed carriers will be aggregated with unlicensed carriers in order to opportunistically enhance downlink user throughput while still offering seamless mobility support. In order to coexist with WiFi, some of the new functionalities required of LAA LTE include a mechanism for channel sensing based on listen-before-talk, Discontinuous Transmission on a carrier with limited maximum Transmission duration, and multicarrier Transmission across multiple unlicensed channels. This article presents a detailed overview of the design agreements for LAA, the impact of unlicensed spectrum operation on the LTE physical layer architecture, and the scope of additional enhancements beyond LTE Release 13. A range of simulations for indoor and multicarrier scenarios show that fair coexistence between LAA and WiFi can be achieved, and that deployment of LAA can provide a boost in WiFi performance.

  • system architecture and coexistence evaluation of licensed assisted access lte with ieee 802 11
    International Conference on Communications, 2015
    Co-Authors: Amitav Mukherjee, Jungfu Cheng, Sorour Falahati, Laetitia Falconetti, Anders Furuskar, Bruhtesfa Godana, Du Ho Kang, Havish Koorapaty, Daniel Larsson, Yu Yang
    Abstract:

    Licensed-assisted access (LAA) is a new operation mode of Long-Term Evolution (LTE) in the unlicensed spectrum currently under study in the 3GPP standardization forum. In order to coexist with Wi-Fi, some of the new functionalities required of LAA LTE include a mechanism for clear channel assessment based on listen-before-talk (LBT), Discontinuous Transmission on a carrier with limited maximum Transmission duration, and dynamic frequency selection (DFS) for radar avoidance in certain frequency bands. This paper presents a detailed overview of the impact of unlicensed spectrum operation on the LTE physical layer architecture, such as downlink physical channel design, scheduling, and radio resource management. System-level simulation results are then presented for indoor and outdoor scenarios, and show that fair coexistence between LAA and Wi-Fi can be achieved and that deployment of LAA can provide a boost in Wi-Fi performance.

Laetitia Falconetti - One of the best experts on this subject based on the ideXlab platform.

  • design and evaluation of licensed assisted access lte in unlicensed spectrum
    IEEE Wireless Communications, 2016
    Co-Authors: Laetitia Falconetti, Amitav Mukherjee, Jungfu Cheng, Sorour Falahati, Du Ho Kang, Havish Koorapaty, Reem Karaki, Evanny Obregon, Daniel Larsson
    Abstract:

    Licensed assisted access (LAA) is a new feature for 3GPP LTE systems to operate in the unlicensed spectrum. Under LAA, licensed carriers will be aggregated with unlicensed carriers in order to opportunistically enhance user throughput, while still offering seamless mobility and outdoor coverage. In order to coexist with other technologies in the unlicensed bands, several new functionalities for LAA LTE have been introduced, including longterm channel selection, short-term channel sensing based on listen-before-talk (LBT), and Discontinuous Transmission on a carrier with limited maximum Transmission duration. In this article, we present research findings behind the designs for LAA systems. We discuss the impact of several parameters of the LAA LBT framework on the channel access opportunities of LAA, and its coexistence performance toward co-channel networks based on extensive system-level simulation results. The investigation covers both single-channel as well as multi-channel operation and coexistence scenarios. In addition to the finalized designs for downlink LAA operations in Release 13, our findings in this article further shed light on the uplink LAA operations to be introduced in Release 14.

  • licensed assisted access lte coexistence with ieee 802 11 and the evolution toward 5g
    IEEE Communications Magazine, 2016
    Co-Authors: Amitav Mukherjee, Jungfu Cheng, Sorour Falahati, Laetitia Falconetti, Du Ho Kang, Havish Koorapaty, Reem Karaki, Daniel Larsson
    Abstract:

    LAA is a new operation mode of LTE in the unlicensed spectrum, which will be featured in LTE Release 13. Under LAA, licensed carriers will be aggregated with unlicensed carriers in order to opportunistically enhance downlink user throughput while still offering seamless mobility support. In order to coexist with WiFi, some of the new functionalities required of LAA LTE include a mechanism for channel sensing based on listen-before-talk, Discontinuous Transmission on a carrier with limited maximum Transmission duration, and multicarrier Transmission across multiple unlicensed channels. This article presents a detailed overview of the design agreements for LAA, the impact of unlicensed spectrum operation on the LTE physical layer architecture, and the scope of additional enhancements beyond LTE Release 13. A range of simulations for indoor and multicarrier scenarios show that fair coexistence between LAA and WiFi can be achieved, and that deployment of LAA can provide a boost in WiFi performance.

  • system architecture and coexistence evaluation of licensed assisted access lte with ieee 802 11
    International Conference on Communications, 2015
    Co-Authors: Amitav Mukherjee, Jungfu Cheng, Sorour Falahati, Laetitia Falconetti, Anders Furuskar, Bruhtesfa Godana, Du Ho Kang, Havish Koorapaty, Daniel Larsson, Yu Yang
    Abstract:

    Licensed-assisted access (LAA) is a new operation mode of Long-Term Evolution (LTE) in the unlicensed spectrum currently under study in the 3GPP standardization forum. In order to coexist with Wi-Fi, some of the new functionalities required of LAA LTE include a mechanism for clear channel assessment based on listen-before-talk (LBT), Discontinuous Transmission on a carrier with limited maximum Transmission duration, and dynamic frequency selection (DFS) for radar avoidance in certain frequency bands. This paper presents a detailed overview of the impact of unlicensed spectrum operation on the LTE physical layer architecture, such as downlink physical channel design, scheduling, and radio resource management. System-level simulation results are then presented for indoor and outdoor scenarios, and show that fair coexistence between LAA and Wi-Fi can be achieved and that deployment of LAA can provide a boost in Wi-Fi performance.

Yanxiang Jiang - One of the best experts on this subject based on the ideXlab platform.

  • enhancing performance of random caching in large scale heterogeneous wireless networks with random Discontinuous Transmission
    IEEE Transactions on Communications, 2018
    Co-Authors: Wanli Wen, Ying Cui, Fuchun Zheng, Shi Jin, Yanxiang Jiang
    Abstract:

    To make better use of file diversity provided by random caching and improve the successful Transmission probability (STP) of a file, we consider reTransmissions with random Discontinuous Transmission (DTX) in a large-scale cache-enabled heterogeneous wireless network employing random caching. We analyze and optimize the STP in two mobility scenarios, i.e., the high mobility scenario and the static scenario. First, in each scenario, by using tools from stochastic geometry, we obtain a closed-form expression for the STP in the general signal-to-interference ratio (SIR) threshold regime. The analysis shows that a larger caching probability corresponds to a higher STP in both scenarios; random DTX can improve the STP in the static scenario and its benefit gradually diminishes when mobility increases. In each scenario, we also derive a closed-form expression for the asymptotic outage probability in the low SIR threshold regime. The asymptotic analysis shows that the diversity gain is jointly affected by random caching and random DTX in both scenarios. Then, in each scenario, we consider the maximization of the STP with respect to the caching probability and the BS activity probability, which is a challenging non-convex optimization problem with a complex objective function. In particular, in the high mobility scenario, we obtain a globally optimal solution. In the static scenario, we develop a low-complexity iterative algorithm to obtain a stationary point. Finally, numerical results show that the proposed solutions achieve significant gains over existing baseline schemes and can well adapt to the changes of the system parameters to wisely utilize storage resources and Transmission opportunities.

  • enhancing performance of random caching in large scale heterogeneous wireless networks with random Discontinuous Transmission
    arXiv: Information Theory, 2018
    Co-Authors: Wanli Wen, Ying Cui, Fuchun Zheng, Shi Jin, Yanxiang Jiang
    Abstract:

    To make better use of file diversity provided by random caching and improve the successful Transmission probability (STP) of a file, we consider reTransmissions with random Discontinuous Transmission (DTX) in a large-scale cache-enabled heterogeneous wireless network (HetNet) employing random caching. We analyze and optimize the STP in two mobility scenarios, i.e., the high mobility scenario and the static scenario. First, in each scenario, by using tools from stochastic geometry, we obtain the closed-form expressions for the STP in the general and low signal-to-interference ratio (SIR) threshold regimes, respectively. The analysis shows that a larger caching probability corresponds to a higher STP in both scenarios; random DTX can improve the STP in the static scenario and its benefit gradually diminishes when mobility increases. Then, in each scenario, we consider the maximization of the STP with respect to the caching probability and the BS activity probability, which is a challenging non-convex optimization problem. In particular, in the high mobility scenario, we obtain a globally optimal solution using interior point method. In the static scenario, we develop a low-complexity iterative algorithm to obtain a stationary point using alternating optimization. Finally, numerical results show that the proposed solutions achieve significant gains over existing baseline schemes and can well adapt to the changes of the system parameters to wisely utilize storage resources and Transmission opportunities.