The Experts below are selected from a list of 11400 Experts worldwide ranked by ideXlab platform
Marios Kountouris - One of the best experts on this subject based on the ideXlab platform.
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Throughput Optimization, Spectrum Allocation, and Access Control in Two-Tier Femtocell Networks
IEEE Journal on Selected Areas in Communications, 2012Co-Authors: W.c. Cheung, Tony Q.s. Quek, Marios KountourisAbstract:The deployment of Femtocells in a macrocell network is an economical and effective way to increase network capacity and coverage. Nevertheless, such deployment is challenging due to the presence of inter-tier and intra-tier interference, and the ad hoc operation of Femtocells. Motivated by the flexible subchannel allocation capability of OFDMA, we investigate the effect of spectrum allocation in two-tier networks, where the macrocells employ closed access policy and the Femtocells can operate in either open or closed access. By introducing a tractable model, we derive the success probability for each tier under different spectrum allocation and femtocell access policies. In particular, we consider joint subchannel allocation, in which the whole spectrum is shared by both tiers, as well as disjoint subchannel allocation, whereby disjoint sets of subchannels are assigned to both tiers. We formulate the throughput maximization problem subject to quality of service constraints in terms of success probabilities and per-tier minimum rates, and provide insights into the optimal spectrum allocation. Our results indicate that with closed access Femtocells, the optimized joint and disjoint subchannel allocations provide the highest throughput among all schemes in sparse and dense femtocell networks, respectively. With open access Femtocells, the optimized joint subchannel allocation provides the highest possible throughput for all femtocell densities.
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Access Control and Cell Association in Two-Tier Femtocell Networks
2012Co-Authors: W.c. Cheung, Tony Q.s. Quek, Marios KountourisAbstract:Two-tier femtocell networks, which comprise macro-cells underlaid with short range Femtocells, are under intensive study due to their improved indoor coverage and data rate advantages as compared to conventional single-tier macrocellular networks. Nevertheless, the implementation of two-tier networks with universal frequency reuse causes severe cross-tier interference from the Femtocells to the macrocellular users, exacerbated by dense femtocell deployment. In this paper, we investigate the effect of access control and cell association in two-tier networks, where the macrocells employ closed access, whereas the Femtocells can operate in either open or closed access. By introducing a tractable model, we derive the success probability for each tier under different femtocell access schemes using stochastic geometric tools. For the case of open access, we derive the enhanced success probability for a macrocell user, and we show that the effect of inter-tier interference could be eliminated through optimal cell association policy for the open access.
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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frequency swapping aided Femtocells in twin layer cellular networks relying on fractional frequency reuse
Wireless Communications and Networking Conference, 2012Co-Authors: Fan Jin, 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 Area Spectral Efficiency (ASE), 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 investigate the Outage Probability (OP) of twin-layer cellular networks, where the Macrocell Base Stations (MBSs) employing Fractional Frequency Reuse (FFR) host the Femtocell Base Stations (FBSs). More explicitly, the frequency-swapping aided femtocell concept is proposed for overcoming the typical near-far problem. We derive the approximate closed-form expressions for the DownLink (DL) OP for both our benchmarker as well as for our proposed solution. Our analysis demonstrates that 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 swapped-spectrum access policy.
Andrzej Duda - One of the best experts on this subject based on the ideXlab platform.
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An Energy Efficient Cell Selection Scheme for Open Access Femtocell Networks
2012Co-Authors: Antonio De Domenico, Emilio Calvanese Strinati, Andrzej DudaAbstract:The exponential increase in high rate traffic driven by a new generation of wireless devices is expected to overload cellular network capacity in the near future. Femtocells have recently been proposed as an efficient and cost-effective approach to enhance cellular network capacity and coverage. However, dense and unplanned deployment of additional Base Stations and their uncoordinated operation may increase the system power consumption. Thus, efficient schemes are essential for managing Femtocells activity and improving the system performance. In this paper, we investigate the effect of femtocell deployment on the cellular network energy efficiency. The goal is twofold: first, we aim to analyse how classic femtocell access schemes affect the system energy consumption; second, we propose a novel cell selection scheme for Open Access Femtocells that allows the effective deployment of Femtocells in the cellular network reducing power consumption and limiting the effect of interference.
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Ghost Femtocells: A novel radio resource management scheme for OFDMA based networks
2011 IEEE Wireless Communications and Networking Conference WCNC 2011, 2011Co-Authors: Emilio Calvanese Strinati, Anna Duda, Antonio De Domenico, Andrzej DudaAbstract:The femtocell deployment in 3GPP/LTE sets new challenges to interference mitigation techniques and Radio Resource Management (RRM). Traditional schemes are mainly designed for classical cellular networks while the ad hoc nature of Femtocells notably limits the complexity of possible algorithms. Thus, efficient RRM schemes are essential for limiting the interference impact on end-user performance. The goal of this paper is to achieve effective spectral reuse between macrocells and Femtocells while guaranteeing the QoS of users served by both macro and femto base stations. We propose a novel resource management scheme that limits the overall interference per chunk generated outside the coverage range of a femtocell while reducing the transmission power in each Resource Block (RB). Our simulation results show that the proposed RRM scheme enhances the energy efficiency of Femtocells and improves both macrocell and femtocell throughput.
W.c. Cheung - One of the best experts on this subject based on the ideXlab platform.
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Throughput Optimization, Spectrum Allocation, and Access Control in Two-Tier Femtocell Networks
IEEE Journal on Selected Areas in Communications, 2012Co-Authors: W.c. Cheung, Tony Q.s. Quek, Marios KountourisAbstract:The deployment of Femtocells in a macrocell network is an economical and effective way to increase network capacity and coverage. Nevertheless, such deployment is challenging due to the presence of inter-tier and intra-tier interference, and the ad hoc operation of Femtocells. Motivated by the flexible subchannel allocation capability of OFDMA, we investigate the effect of spectrum allocation in two-tier networks, where the macrocells employ closed access policy and the Femtocells can operate in either open or closed access. By introducing a tractable model, we derive the success probability for each tier under different spectrum allocation and femtocell access policies. In particular, we consider joint subchannel allocation, in which the whole spectrum is shared by both tiers, as well as disjoint subchannel allocation, whereby disjoint sets of subchannels are assigned to both tiers. We formulate the throughput maximization problem subject to quality of service constraints in terms of success probabilities and per-tier minimum rates, and provide insights into the optimal spectrum allocation. Our results indicate that with closed access Femtocells, the optimized joint and disjoint subchannel allocations provide the highest throughput among all schemes in sparse and dense femtocell networks, respectively. With open access Femtocells, the optimized joint subchannel allocation provides the highest possible throughput for all femtocell densities.
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Access Control and Cell Association in Two-Tier Femtocell Networks
2012Co-Authors: W.c. Cheung, Tony Q.s. Quek, Marios KountourisAbstract:Two-tier femtocell networks, which comprise macro-cells underlaid with short range Femtocells, are under intensive study due to their improved indoor coverage and data rate advantages as compared to conventional single-tier macrocellular networks. Nevertheless, the implementation of two-tier networks with universal frequency reuse causes severe cross-tier interference from the Femtocells to the macrocellular users, exacerbated by dense femtocell deployment. In this paper, we investigate the effect of access control and cell association in two-tier networks, where the macrocells employ closed access, whereas the Femtocells can operate in either open or closed access. By introducing a tractable model, we derive the success probability for each tier under different femtocell access schemes using stochastic geometric tools. For the case of open access, we derive the enhanced success probability for a macrocell user, and we show that the effect of inter-tier interference could be eliminated through optimal cell association policy for the open access.
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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frequency swapping aided Femtocells in twin layer cellular networks relying on fractional frequency reuse
Wireless Communications and Networking Conference, 2012Co-Authors: Fan Jin, 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 Area Spectral Efficiency (ASE), 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 investigate the Outage Probability (OP) of twin-layer cellular networks, where the Macrocell Base Stations (MBSs) employing Fractional Frequency Reuse (FFR) host the Femtocell Base Stations (FBSs). More explicitly, the frequency-swapping aided femtocell concept is proposed for overcoming the typical near-far problem. We derive the approximate closed-form expressions for the DownLink (DL) OP for both our benchmarker as well as for our proposed solution. Our analysis demonstrates that 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 swapped-spectrum access policy.
