The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Lajos Hanzo - One of the best experts on this subject based on the ideXlab platform.
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fractional frequency reuse aided twin layer femtocell networks analysis design and optimization
IEEE Transactions on Communications, 2013Co-Authors: Rong Zhang, Lajos HanzoAbstract:Femtocells constitute an economical solution conceived for improving the indoor coverage, which are capable of achieving a high network capacity. In order to guarantee a high Spectral Efficiency (SE), femtocells have to reuse the spectrum of Macrocells. As a result, the performance of both the femtocells and Macrocells may suffer owing to the near-far effects. In this paper, we study a twin-layer cellular networks, where the Macrocell Base Stations (MBSs) employing Fractional Frequency Reuse (FFR) host the Femtocell Base Stations (FBSs). This paper investigates the design, performance analysis and optimization problems of this FFR aided twin-layer network. We firstly assume that the femtocells opt for full spectrum access (FSA). The per-layer outage probability (OP) is derived and the network is optimized for maximizing the Macrocell's throughput. We found that the advantage of FFR eroded in dense femtocell-scenarios and the optimized network tends to become a Unity Frequency Reuse (UFR) aided system. We then propose a spectrum swapping access (SSA) strategy for protecting the Macrocell's performance and for overcoming the typical near-far problem. Our analysis demonstrates that both the OP of femtocell users in the Cell Centre Region (CCR) and that of the Macrocell users in the Cell Edge Region (CER) will be reduced by the proposed SSA. The optimized network using our SSA is more robust to the detrimental impact of femtocells.
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fractional frequency reuse aided twin layer femtocell networks analysis design and optimization
IEEE Transactions on Communications, 2013Co-Authors: Rong Zhang, Lajos HanzoAbstract:Femtocells constitute an economical solution conceived for improving the indoor coverage, which are capable of achieving a high network capacity. In order to guarantee a high Spectral Efficiency (SE), femtocells have to reuse the spectrum of Macrocells. As a result, the performance of both the femtocells and Macrocells may suffer owing to the near-far effects. In this paper, we study a twin-layer cellular networks, where the Macrocell Base Stations (MBSs) employing Fractional Frequency Reuse (FFR) host the Femtocell Base Stations (FBSs). This paper investigates the design, performance analysis and optimization problems of this FFR aided twin-layer network. We firstly assume that the femtocells opt for full spectrum access (FSA). The per-layer outage probability (OP) is derived and the network is optimized for maximizing the Macrocell's throughput. We found that the advantage of FFR eroded in dense femtocell-scenarios and the optimized network tends to become a Unity Frequency Reuse (UFR) aided system. We then propose a spectrum swapping access (SSA) strategy for protecting the Macrocell's performance and for overcoming the typical near-far problem. Our analysis demonstrates that both the OP of femtocell users in the Cell Centre Region (CCR) and that of the Macrocell users in the Cell Edge Region (CER) will be reduced by the proposed SSA. The optimized network using our SSA is more robust to the detrimental impact of femtocells.
Rong Zhang - One of the best experts on this subject based on the ideXlab platform.
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fractional frequency reuse aided twin layer femtocell networks analysis design and optimization
IEEE Transactions on Communications, 2013Co-Authors: Rong Zhang, Lajos HanzoAbstract:Femtocells constitute an economical solution conceived for improving the indoor coverage, which are capable of achieving a high network capacity. In order to guarantee a high Spectral Efficiency (SE), femtocells have to reuse the spectrum of Macrocells. As a result, the performance of both the femtocells and Macrocells may suffer owing to the near-far effects. In this paper, we study a twin-layer cellular networks, where the Macrocell Base Stations (MBSs) employing Fractional Frequency Reuse (FFR) host the Femtocell Base Stations (FBSs). This paper investigates the design, performance analysis and optimization problems of this FFR aided twin-layer network. We firstly assume that the femtocells opt for full spectrum access (FSA). The per-layer outage probability (OP) is derived and the network is optimized for maximizing the Macrocell's throughput. We found that the advantage of FFR eroded in dense femtocell-scenarios and the optimized network tends to become a Unity Frequency Reuse (UFR) aided system. We then propose a spectrum swapping access (SSA) strategy for protecting the Macrocell's performance and for overcoming the typical near-far problem. Our analysis demonstrates that both the OP of femtocell users in the Cell Centre Region (CCR) and that of the Macrocell users in the Cell Edge Region (CER) will be reduced by the proposed SSA. The optimized network using our SSA is more robust to the detrimental impact of femtocells.
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fractional frequency reuse aided twin layer femtocell networks analysis design and optimization
IEEE Transactions on Communications, 2013Co-Authors: Rong Zhang, Lajos HanzoAbstract:Femtocells constitute an economical solution conceived for improving the indoor coverage, which are capable of achieving a high network capacity. In order to guarantee a high Spectral Efficiency (SE), femtocells have to reuse the spectrum of Macrocells. As a result, the performance of both the femtocells and Macrocells may suffer owing to the near-far effects. In this paper, we study a twin-layer cellular networks, where the Macrocell Base Stations (MBSs) employing Fractional Frequency Reuse (FFR) host the Femtocell Base Stations (FBSs). This paper investigates the design, performance analysis and optimization problems of this FFR aided twin-layer network. We firstly assume that the femtocells opt for full spectrum access (FSA). The per-layer outage probability (OP) is derived and the network is optimized for maximizing the Macrocell's throughput. We found that the advantage of FFR eroded in dense femtocell-scenarios and the optimized network tends to become a Unity Frequency Reuse (UFR) aided system. We then propose a spectrum swapping access (SSA) strategy for protecting the Macrocell's performance and for overcoming the typical near-far problem. Our analysis demonstrates that both the OP of femtocell users in the Cell Centre Region (CCR) and that of the Macrocell users in the Cell Edge Region (CER) will be reduced by the proposed SSA. The optimized network using our SSA is more robust to the detrimental impact of femtocells.
Hiroyuki Ishii - One of the best experts on this subject based on the ideXlab platform.
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future steps of lte a evolution toward integration of local area and wide area systems
IEEE Wireless Communications, 2013Co-Authors: Yoshihisa Kishiyama, A Benjebbour, Takehiro Nakamura, Hiroyuki IshiiAbstract:In the future steps of 3GPP LTE-Advanced, we will need to ensure the sustainability of 3GPP radio access technologies in order to respond to the anticipated challenging requirements of the future. To this end, this article presents our views on the evolution concept and candidate technologies for future steps of LTE-A taking into account the ever increasing importance of local area (small cells) and the need for further spectrum extension to higher frequency bands. In our evolution concept, we emphasize the integration of the local area with the wide area as a new form of cooperation between conventional Macrocells in lower frequency bands and small cells deployed in higher frequency bands. Furthermore, we identify the potential key technologies for further spectrum efficiency enhancements for both the local area and the wide area, and for the efficient integration of the local and wide areas while assuming frequency separation between Macrocells and small cells. In particular, multicell cooperation based on Macrocell assistance of small cells (referred to as Phantom cell) is introduced, and the related benefits are discussed. Finally, in order to demonstrate the potential capacity gains of our evolution concept, system-level simulation results are provided for using outdoor small cells in higher/wider frequency bands.
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future steps of lte a evolution toward integration of local area and wide area systems
IEEE Wireless Communications, 2013Co-Authors: Yoshihisa Kishiyama, A Benjebbour, Takehiro Nakamura, Hiroyuki IshiiAbstract:In the future steps of 3GPP LTE-Advanced, we will need to ensure the sustainability of 3GPP radio access technologies in order to respond to the anticipated challenging requirements of the future. To this end, this article presents our views on the evolution concept and candidate technologies for future steps of LTE-A taking into account the ever increasing importance of local area (small cells) and the need for further spectrum extension to higher frequency bands. In our evolution concept, we emphasize the integration of the local area with the wide area as a new form of cooperation between conventional Macrocells in lower frequency bands and small cells deployed in higher frequency bands. Furthermore, we identify the potential key technologies for further spectrum efficiency enhancements for both the local area and the wide area, and for the efficient integration of the local and wide areas while assuming frequency separation between Macrocells and small cells. In particular, multicell cooperation based on Macrocell assistance of small cells (referred to as Phantom cell) is introduced, and the related benefits are discussed. Finally, in order to demonstrate the potential capacity gains of our evolution concept, system-level simulation results are provided for using outdoor small cells in higher/wider frequency bands.
Yoshihisa Kishiyama - One of the best experts on this subject based on the ideXlab platform.
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system level performance of downlink non orthogonal multiple access noma under various environments
Vehicular Technology Conference, 2015Co-Authors: Yuya Saito, Yoshihisa Kishiyama, A Benjebbour, Takehiro NakamuraAbstract:Non-orthogonal multiple access (NOMA) is a promising multiple access scheme for further improving the spectrum efficiency compared to that for orthogonal multiple access (OMA) in the 5th Generation (5G) mobile communication systems. All of the existing evaluations for NOMA focus on the Macrocell deployment since NOMA fully utilizes the power domain and the difference in channel gains, e.g., path loss, between users, which is typically sufficiently large in Macrocells. Currently, small cells are becoming important and being studied for future Long-Term Evolution (LTE) enhancements in order to improve further the system performance. Thus, it is of great interest to study the performance of NOMA for small cell deployment under various environments. This paper investigates the system level performance of NOMA in small cells considering practical assumptions such as the single user multiple-input multiple-output (SU-MIMO) technique, adaptive modulation and coding (AMC), feedback channel quality indicator (CQI). Some of the key NOMA specific functionalities, including multi-user paring and transmit power allocation are also taken into account in the evaluation. Based on computer simulations, we show that for both Macrocell and small cell deployments, NOMA can still provide a larger throughput performance gain compared to that for OMA.
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future steps of lte a evolution toward integration of local area and wide area systems
IEEE Wireless Communications, 2013Co-Authors: Yoshihisa Kishiyama, A Benjebbour, Takehiro Nakamura, Hiroyuki IshiiAbstract:In the future steps of 3GPP LTE-Advanced, we will need to ensure the sustainability of 3GPP radio access technologies in order to respond to the anticipated challenging requirements of the future. To this end, this article presents our views on the evolution concept and candidate technologies for future steps of LTE-A taking into account the ever increasing importance of local area (small cells) and the need for further spectrum extension to higher frequency bands. In our evolution concept, we emphasize the integration of the local area with the wide area as a new form of cooperation between conventional Macrocells in lower frequency bands and small cells deployed in higher frequency bands. Furthermore, we identify the potential key technologies for further spectrum efficiency enhancements for both the local area and the wide area, and for the efficient integration of the local and wide areas while assuming frequency separation between Macrocells and small cells. In particular, multicell cooperation based on Macrocell assistance of small cells (referred to as Phantom cell) is introduced, and the related benefits are discussed. Finally, in order to demonstrate the potential capacity gains of our evolution concept, system-level simulation results are provided for using outdoor small cells in higher/wider frequency bands.
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future steps of lte a evolution toward integration of local area and wide area systems
IEEE Wireless Communications, 2013Co-Authors: Yoshihisa Kishiyama, A Benjebbour, Takehiro Nakamura, Hiroyuki IshiiAbstract:In the future steps of 3GPP LTE-Advanced, we will need to ensure the sustainability of 3GPP radio access technologies in order to respond to the anticipated challenging requirements of the future. To this end, this article presents our views on the evolution concept and candidate technologies for future steps of LTE-A taking into account the ever increasing importance of local area (small cells) and the need for further spectrum extension to higher frequency bands. In our evolution concept, we emphasize the integration of the local area with the wide area as a new form of cooperation between conventional Macrocells in lower frequency bands and small cells deployed in higher frequency bands. Furthermore, we identify the potential key technologies for further spectrum efficiency enhancements for both the local area and the wide area, and for the efficient integration of the local and wide areas while assuming frequency separation between Macrocells and small cells. In particular, multicell cooperation based on Macrocell assistance of small cells (referred to as Phantom cell) is introduced, and the related benefits are discussed. Finally, in order to demonstrate the potential capacity gains of our evolution concept, system-level simulation results are provided for using outdoor small cells in higher/wider frequency bands.
Takehiro Nakamura - One of the best experts on this subject based on the ideXlab platform.
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system level performance of downlink non orthogonal multiple access noma under various environments
Vehicular Technology Conference, 2015Co-Authors: Yuya Saito, Yoshihisa Kishiyama, A Benjebbour, Takehiro NakamuraAbstract:Non-orthogonal multiple access (NOMA) is a promising multiple access scheme for further improving the spectrum efficiency compared to that for orthogonal multiple access (OMA) in the 5th Generation (5G) mobile communication systems. All of the existing evaluations for NOMA focus on the Macrocell deployment since NOMA fully utilizes the power domain and the difference in channel gains, e.g., path loss, between users, which is typically sufficiently large in Macrocells. Currently, small cells are becoming important and being studied for future Long-Term Evolution (LTE) enhancements in order to improve further the system performance. Thus, it is of great interest to study the performance of NOMA for small cell deployment under various environments. This paper investigates the system level performance of NOMA in small cells considering practical assumptions such as the single user multiple-input multiple-output (SU-MIMO) technique, adaptive modulation and coding (AMC), feedback channel quality indicator (CQI). Some of the key NOMA specific functionalities, including multi-user paring and transmit power allocation are also taken into account in the evaluation. Based on computer simulations, we show that for both Macrocell and small cell deployments, NOMA can still provide a larger throughput performance gain compared to that for OMA.
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future steps of lte a evolution toward integration of local area and wide area systems
IEEE Wireless Communications, 2013Co-Authors: Yoshihisa Kishiyama, A Benjebbour, Takehiro Nakamura, Hiroyuki IshiiAbstract:In the future steps of 3GPP LTE-Advanced, we will need to ensure the sustainability of 3GPP radio access technologies in order to respond to the anticipated challenging requirements of the future. To this end, this article presents our views on the evolution concept and candidate technologies for future steps of LTE-A taking into account the ever increasing importance of local area (small cells) and the need for further spectrum extension to higher frequency bands. In our evolution concept, we emphasize the integration of the local area with the wide area as a new form of cooperation between conventional Macrocells in lower frequency bands and small cells deployed in higher frequency bands. Furthermore, we identify the potential key technologies for further spectrum efficiency enhancements for both the local area and the wide area, and for the efficient integration of the local and wide areas while assuming frequency separation between Macrocells and small cells. In particular, multicell cooperation based on Macrocell assistance of small cells (referred to as Phantom cell) is introduced, and the related benefits are discussed. Finally, in order to demonstrate the potential capacity gains of our evolution concept, system-level simulation results are provided for using outdoor small cells in higher/wider frequency bands.
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future steps of lte a evolution toward integration of local area and wide area systems
IEEE Wireless Communications, 2013Co-Authors: Yoshihisa Kishiyama, A Benjebbour, Takehiro Nakamura, Hiroyuki IshiiAbstract:In the future steps of 3GPP LTE-Advanced, we will need to ensure the sustainability of 3GPP radio access technologies in order to respond to the anticipated challenging requirements of the future. To this end, this article presents our views on the evolution concept and candidate technologies for future steps of LTE-A taking into account the ever increasing importance of local area (small cells) and the need for further spectrum extension to higher frequency bands. In our evolution concept, we emphasize the integration of the local area with the wide area as a new form of cooperation between conventional Macrocells in lower frequency bands and small cells deployed in higher frequency bands. Furthermore, we identify the potential key technologies for further spectrum efficiency enhancements for both the local area and the wide area, and for the efficient integration of the local and wide areas while assuming frequency separation between Macrocells and small cells. In particular, multicell cooperation based on Macrocell assistance of small cells (referred to as Phantom cell) is introduced, and the related benefits are discussed. Finally, in order to demonstrate the potential capacity gains of our evolution concept, system-level simulation results are provided for using outdoor small cells in higher/wider frequency bands.
