A novel metric to study the performance of sectorized fractional frequency reuse techniques in LTE
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LTE Femtocells are designed to increase capacity and coverage especially for the indoor and cell-edge mobile users. Typically, they are deployed to offload the macrocell. However, due to co-location of femtocells in macrocell coverage, the co-tier and cross-tier interferences are high. Fractional Frequency Reuse mechanism (FFR) is one of the most effective femtocell interference avoidance techniques. In this paper, we propose a new metric to determine optimal inner region radius and frequency allocation which optimizes the total cell throughput and serves as many number of users in the network. We already know that FFR technique is designed to better serve cell edge users. With introduction of new metric, we extend that idea to serve as many users in the network. The new metric is applied to sectorized FFR configurations and their performance is evaluated under different network conditions.Keywords:
Macrocell
Femtocell
Frequency allocation
Frequency reuse
Trunking
: Femtocell is a low powered small base station that operates on licensed frequency band. Femtocells are deployed by users to improve indoor coverage. Femtocells and the outer macrocell can co-exist with dedicated spectrum allocation or shared spectrum allocation strategy to avoid interference. The dedicated spectrum allocation strategy is not cost-effective as spectrum resource is limited. However the shared spectrum allocation strategy where the femtocells share the same frequency bands with the macrocell is an efficient solution, but demands specialized inter-cell interference management techniques. This paper investigates the characteristics of dense femtocells and its various access control modes and provides an overview of resource allocation, open issues and challenges for interference avoidance in dense OFDMA hybrid access femtocells.
Femtocell
Macrocell
Femto-
Frequency allocation
Spectral Efficiency
Radio spectrum
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This paper considers the problem of subcarrier scheduling in the downlink of multicell OFDMA networks. It proposes a dynamic fractional frequency reuse cell architecture that partitions subcarriers into two groups. One is reused in the whole cell area whereas the other is partitioned into sectors and used orthogonally. The proposed architecture allows dynamic allocation of users to the group of subcarriers. This dynamic allocation of users is different from the existing architectures where users are partitioned according to fixed thresholds. Next, we propose an efficient hierarchical solution which first allocates subcarriers to the groups and next opportunistically schedules subcarriers to the users. The overall scheme allows frequency reuse factor of 1 with reduced inter-cell interference, increased trunking gain and satisfied minimum data rate requirements. Simulation results illustrate the usefulness of the proposed solution.
Trunking
Frequency reuse
Frequency allocation
Channel allocation schemes
Frequency-division multiple access
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Deployment of femtocells (Home eNode Bs) along with existing macrocells has been drawn considerable attention of mobile industry because of its potential to reduce Operational Expenditure to the operators by offloading traffic from macrocell to femtocells. In this paper, we evaluate the energy efficiency of co-channel deployed macrocell-femtocell networks considering centralized control for HeNBs. We also show the impact of macro-cell power configuration on the energy efficiency. The results show that significant amount of improvement in energy efficiency can be achieved by centrally coordinating macrocell and femtocell networks, according to varying traffic load condition without affecting the Quality of Service requirements of macrocell and femtocell users.
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Macrocell
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Recently, Long Term Evolution (LTE) has developed a femtocell for indoor coverage extension. However, interference problem between the femtocell and the macrocell should be solved in advance. In this paper, we propose an interference management scheme in the LTE femtocell systems using Fractional Frequency Reuse (FFR). Under the macrocell allocating frequency band by the FFR, the femtocell chooses sub-bands which are not used in the macrocell sub-area to avoid interference. Simulation results show that proposed scheme enhances total/edge throughputs and reduces the outage probability in overall network, especially for the cell edge users.
Macrocell
Femtocell
Frequency reuse
LTE Advanced
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Wireless networks employing small cells like femtocells are considered to be the choice of network deployment for 4G or advanced networks. This hierarchical deployment of cells introduces the necessity of effective frequency planning for mitigation of interference between different layers of network. As the scarce spectrum resources are likely to be reused to increase spectral efficiency, interference free signal reception has to be guaranteed to ensure better quality of service (QoS). In this paper we propose a dynamic frequency reuse scheme for the deployment of femtocells within a macrocell with the femtocells reusing the spectrum of neighbouring macrocells. We also provide a protective scheme for cell edge femtocell users as they are vulnerable to interference signals from neighbouring macrocells. A detailed frequency planning is provided to maximize spectral reuse while providing maximum throughput. We compare our proposed scheme with other frequency allocation schemes already described in literature. Simulation results shows that our scheme provides better throughput and ensures lower outage probability.
Macrocell
Femtocell
Frequency allocation
Spectral Efficiency
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Femtocell has appeared as a solution to increase both coverage and capacity of cellular networks. However, interference problem between the macrocell and the femtocell must be solved before any deployment. In this paper, we deal with the problem of joint subband, rate, and power allocation in OFDMA based two-tier femtocell networks. It is assumed that for macrocell users, spectrum allocation is accomplished through Fractional Frequency Reuse (FFR). Our objective is to maximize the femtocell user's throughput while maintaining as little as possible reduction in the macrocell users' performance. Our proposed algorithm is decentralized, and needs to be done only when femtocell access point is plugged in, based on some measurements. Simulation results show superior performance of the proposed scheme compared to the other methods.
Macrocell
Femtocell
Frequency reuse
Frequency allocation
Frequency-division multiple access
Transmitter power output
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For indoor coverage extension Long Term Evolution (LTE) has developed a Femtocell. However, in advance we should solve the interference problem between the femtocell and the macrocell. Here, we propose a scheme to interference mitigation in the LTE femtocell systems using Fractional Frequency Reuse (FFR). By the FFR under the macrocell allocating a frequency band, to avoid interference the femtocell select those sub-bands which are not used in the macrocell sub-area. Simulation results show that proposed scheme improves total/edge throughputs and reduces the outage probability in the overall network.
Macrocell
Femtocell
Femto-
Frequency reuse
LTE Advanced
Macro
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Femtocell
Macrocell
Stackelberg competition
Frequency allocation
Macro
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Femtocells are being deployed for coverage extension and higher data rates. However, interference problem between macrocell and femtocells should be solved before massive deployment. In this paper, we analyze the possible cases of frequency resource allocation in the OFDMA femtocell systems using Fractional Frequency Reuse (FFR) in order to minimize the interference between both cells. Under the assumed pre-allocation of macrocell users with the FFR, the allocable cases of sub-bands for the femtocells are investigated. Efficient and practical guidelines for femtocell's resource allocation are suggested with the consideration of macrocell users having a priority over femtocell users and of enhancing overall throughputs. Simulation results show the enhanced throughputs of both macrocell users and combined total users through practical interference-avoidance guidelines.
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Femtocell
Frequency reuse
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Femtocells (HeNB) are deployed within macrocell coverage area to increase performance of indoor user. In order to cover, all indoor users, HeNBs make a network, known as femtocell network. Since, HeNBs use same spectrum, they are causing interference on both MeNB users (MUE) and among HeNB users (HUE). The performance of the femtocell network depends on the SINR of HUEs of respective HeNBs, which eventually depends on the interference produced on it. In order to improve the performance, we need to minimize the interferences among themselves. In this paper, we first study the SINR performance of HUEs in the macrocell environment. We also analyze the outage probability in femtocell network. Finally, we consider the power consumption issue of femtocell network.
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Femtocell
Femto-
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