Inter-cell interference mitigation using adaptive reduced power subframes in heterogeneous networks

With the remarkable impact and fast growth of the mobile networks, the mobile base stations have been increased too, especially in the high population areas. These base stations will be overloaded by users, for that reason the small cells (like pico cells) were introduced. However, the inter-cell interference will be high in this type of Heterogeneous networks. There are many solutions to mitigate this interference like the inter-cell interference coordination (ICIC), and then the further enhanced ICIC (Fe-ICIC) where the almost blank subframes are used to give priority to the (victim users). But it could be a waste of bandwidth due to the unused subframes. For that reason, in this paper, we proposed an adaptive reduced power subframe that reduces its power ratio according to the user’s signal-to-interference-plus-noise ratio (SINR) in order to get a better throughput and to mitigate the intercell interference. When the user is far from the cell, the case will be considered as an edge user and will get a higher priority to be served first. The results show that the throughput of all users in the macro cells and pico cell will be improved when applying the proposed scheme in term of throughput for the users and the cells.

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Ensuring reliable connectivity to cellular-connected UAVs with up-tilted antennas and interference coordination

ITU Journal on Future and Evolving Technologies ◽

10.52953/left7402 ◽

2021 ◽

Vol 2 (2) ◽

pp. 165-185

Author(s):

Md Moin Uddin Chowdhury ◽

Ismail Guvenc ◽

Walid Saad ◽

Arupjyoti Bhuyan

Keyword(s):

Large Scale ◽

Interference Mitigation ◽

Heuristic Method ◽

Path Loss ◽

Antenna Pattern ◽

Base Stations ◽

Interference Coordination ◽

Minimal Impact ◽

Np Hard Problem ◽

Inter Cell Interference

To integrate unmanned aerial vehicles (UAVs) in future large-scale deployments, a new wireless communication paradigm, namely, the cellular-connected UAV has recently attracted interest. However, the line-of-sight dominant air-to-ground channels along with the antenna pattern of the cellular ground base stations (GBSs) introduce critical interference issues in cellular-connected UAV communications. In particular, the complex antenna pattern and the ground reflection (GR) from the down-tilted antennas create both coverage holes and patchy coverage for the UAVs in the sky, which leads to unreliable connectivity from the underlying cellular network. To overcome these challenges, in this paper, we propose a new cellular architecture that employs an extra set of co-channel antennas oriented towards the sky to support UAVs on top of the existing down-tilted antennas for ground user equipment (GUE). To model the GR stemming from the down-tilted antennas, we propose a path-loss model, which takes both antenna radiation pattern and configuration into account. Next, we formulate an optimization problem to maximize the minimum signal-to-interference ratio (SIR) of the UAVs by tuning the up-tilt (UT) angles of the up-tilted antennas. Since this is an NP-hard problem, we propose a genetic algorithm (GA) based heuristic method to optimize the UT angles of these antennas. After obtaining the optimal UT angles, we integrate the 3GPP Release-10 specified enhanced inter-cell interference coordination (eICIC) to reduce the interference stemming from the down-tilted antennas. Our simulation results based on the hexagonal cell layout show that the proposed interference mitigation method can ensure higher minimum SIRs for the UAVs over baseline methods while creating minimal impact on the SIR of GUEs.

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Game-Theoretic Approaches in Heterogeneous Networks

Game Theory ◽

10.4018/978-1-5225-2594-3.ch009 ◽

2017 ◽

pp. 204-218

Author(s):

Chih-Yu Wang ◽

Hung-Yu Wei ◽

Mehdi Bennis ◽

Athanasios V. Vasilakos

Keyword(s):

Game Theory ◽

Heterogeneous Networks ◽

Small Cells ◽

Efficient Manner ◽

Intercell Interference ◽

Lte Advanced ◽

Game Theoretic ◽

Promising Solution ◽

Cost Efficient ◽

Coverage Holes

Improving capacity and coverage is one of the main issues in next-generation wireless communication. Heterogeneous networks (HetNets), which is currently investigated in LTE-Advanced standard, is a promising solution to enhance capacity and eliminate coverage holes in a cost-efficient manner. A HetNet is composed of existing macrocells and various types of small cells. By deploying small cells into the existing network, operators enhance the users' quality of service which are suffering from severe signal degradation at cell edges or coverage holes. Nevertheless, there are numerous challenges in integrating small cells into the existing cellular network due to the characteristics: unplanned deployment, intercell interference, economic potential, etc. Recently, game theory has been shown to be a powerful tool for investigating the challenges in HetNets. Several game-theoretic approaches have been proposed to model the distributed deployment and self-organization feature of HetNets. In this chapter, the authors first give an overview of the challenges in HetNets. Subsequently, the authors illustrate how game theory can be applied to solve issues related to HetNets.

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Clustering and Auction-Based Power Allocation Algorithm for Energy Efficiency Maximization in Multi-Cell Multi-Carrier NOMA Networks

Applied Sciences ◽

10.3390/app9235034 ◽

2019 ◽

Vol 9 (23) ◽

pp. 5034 ◽

Cited By ~ 1

Author(s):

Abuzar B. M. Adam ◽

Xiaoyu Wan ◽

Zhengqiang Wang

Keyword(s):

Energy Efficiency ◽

Power Allocation ◽

Cooperative Game ◽

Multiple Access ◽

Optimization Problem ◽

Interference Mitigation ◽

Base Stations ◽

Frequency Division ◽

Simulation Results ◽

Inter Cell Interference

In this paper, we investigate the energy efficiency (EE) maximization in multi-cell multi-carrier non-orthogonal multiple access (MCMC-NOMA) networks. To achieve this goal, an optimization problem is formulated then the solution is divided into two parts. First, we investigate the inter-cell interference mitigation and then we propose an auction-based non-cooperative game for power allocation for base stations. Finally, to guarantee the rate requirements for users, power is allocated fairly to users. The simulation results show that the proposed scheme has the best performance compared with the existing NOMA-based fractional transmit power allocation (FTPA) and the conventional orthogonal frequency division multiple access (OFDMA).

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