Adaptive interference mitigation techniques for femtocells (original) (raw)
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International Journal of Computer Applications, 2017
The deployment of small cell node such as femto-cell within macro area coverage has been considered a promising solution to provide better throughput and Quality of Experience (QoE) to users. However, co-channel deployment of femto-cell operating in a closed access mode (CSG) causes severe cross-tier interference. In this paper we have develop an adaptive Hybrid Power control and Time domain Technique (aHPTT) to mitigate cross-tier interference in HetNet. The hybrid technique was developed to handle limitations associated with using a single interference mitigation technique such as Power Control (PC) and Time Domain (TD). aHPTT integrate PC and TD to mitigate interference simultaneously depending on the position of the user in the network. The hybrid technique was implemented in a Graphical User Interface (GUI) using MATLAB R2013a. System level simulation was carried out to evaluate the performance of the hybrid technique in terms of user's throughput. The aHPTT was validated with the 3rd Generation Partnership Project (3GPP) enhance Inter-cell Interference Coordination (eICIC) technique, results obtained showed that the aHPTT performs better than PC technique by 2.90% and TD technique by 82.60%.
A power-control interference management mechanism for Femtocell-based networks
International Journal of High Performance Computing and Networking, 2018
Femtocell deployment is one of the promising solutions to meet the increasing demands on wireless services and applications. Based on deploying Femtocells within the already-existing Macrocells, Femtocells can improve indoor coverage and increase both spectral efficiency and data rate. This improvement can be achieved by reusing the available spectrum assigned for the Macrocells, and being closer to the users. However, Femtocell deployment faces many challenges. One of the most challenging issues is the interference management issue. In this paper, a power-control channel assignment algorithm to manage the interference between Femtocell and Macrocell networks is proposed. The proposed algorithm allows frequency reuse among Femtocell users (FUEs) to provide better throughput performance. Simulation results have shown an improvement in throughput by up to 90% compared to previous schemes.
A review of techniques to avoid cross-tier and co-tier interference in femtocell networks
The Journal of Engineering Research, 2016
Femtocell Networks are the proposed solution for deployment in homes that enables an indoor mobile user to achieve high speed downloading from the internet and make good quality voice calls. A femtocell network also provides relief to an overloaded macrocell network by servicing mobile users at home which without the femtocell network have to be served by the macrocell. However, like all wireless networks, femtocell networks suffer from the problem of interference. This interference can be divided into two types, Cross-tier (between femtocells and macrocells) and Co-tier (between femtocells). The avoidance or management of these two types of interference is crucial to the proper functionality of a femtocell i.e. to provide high data rate and high quality voice calls to indoor mobile users. Several techniques have been proposed in literature to avoid these types of interference. These are cognitive radio, resource allocation, power control, Q-learning and access control. The findings...
Review of interference avoidance schemes in femtocell networks
2011
Femtocell is a solution to increase the system capacity and coverage to meet the high demand of the next generation of services on broadband wireless access. However, the deployment of a new femtocell layer may have an undesired impact on the performance of the macrocell layer. The allocation of spectrum resources and the avoidance of electromagnetic interference are some of the more urgent challenges that operators face before femtocells become widely deployed. In this paper different interference avoidance schemes are described and compared. Special attention is paid to the use of uplink and downlink power control and self-configuration and self-optimization techniques for the avoidance of interference. From the review, we conclude that frequency planning is suitable for interference avoidance schemes for unplanned location of femtocells deployment.
Interference Mitigation for Femto Deployment in Next Generation Mobile Networks
The huge capacity requirements for the next generation mobile network is defining the technologies that will drive the future system. The trio of millimeter wave, massive MIMO and small cell are emerging as the tripod upon which the upcoming network is expected to thrive. With about 80% indoor mobile usage, small cell and by extension, femtocell is projected to deliver the bulk of the predicted mobile traffic. This paper takes an overview of the future 5G network and advances solutions to the most anticipated interference challenges as a result of cell densification.
Scalable and Self-Sustained Algorithms for Femtocell Interference Mitigation
Cellular networks are reaching their physical limits providing capacity that is almost near the Shannon theory. However, cellular usage is still increasing exponentially with hungry applications demanding higher data rates. As a result, designers are facing significant challenge in meeting the required demands. One of the promising solutions, being fostered by the 3GPP, is to increase the spectral efficiency through higher frequency reuse using smaller and denser network cells such as femto, pico and nano cells. One of the main challenges behind using smaller cells is managing interference, in this paper, we propose two novel solutions that alleviate the interference of femto-cells on macro-cell user equipment (MUEs). The solutions do not rely on any additional information exchange or signaling, nor do they rely on the backhaul and it's delay. The first proposal is Femto-cell Power Control Scheme (FPCS) that utilizes an analytical approach to adapt the femto base station's transmit power based on Channel Quality Indicator (CQI) reports from affected MUEs. The second method is Random Physical Resource Block Selection Scheme (RPSS) that allocates the femto-cell's resources from a random subset of Physical Resource Blocks (PRBs) so that the MUEs benefit from a reduced interference level. Our evaluations have shown that the two proposals do alleviate the femto-cell interference significantly, increasing the SINR and enhancing the end performance. To the best of our knowledge, no similar work exist in literature that addresses the femto-cell's interference without information exchange.
Femto-macro cellular interference control with subband scheduling and interference cancelation
2010
Abstract A significant technical challenge in deploying fem-tocells is controlling the interference from the underlay of femtos onto the overlay of macros. This paper presents a novel interference control method where the macrocell bandwidth is partitioned into subbands, and the short-range femtocell links adaptively allocate their power across the subbands based on a load-spillage power control method.
A Review of Radio Resource Management in FemtoCell from Interference Control Perspective
ECTI Transactions on Computer and Information Technology (ECTI-CIT), 2017
A new and emerging technology called femtocell brings significant improvement in terms of better indoor coverage and higher data rate. Able to be installed and maintained by individual user, femtocell provides a cost effective solution to mobile operators to achieve higher network capacity. However, interference due to two-tier network structure introduces many challenges for successful femtocell deployment. In this article, we summarize various interference and resource management techniques proposed in the context of femtocell. Specifically, we focus on interference avoidance techniques. First, the overview of femtocells, its architecture, and common issues are presented. Next, various interference avoidance techniques are reviewed. At the end, several important research directions are outlined.
A Novel Resource Allocation and Power Control Mechanism for Hybrid Access Femtocells
Computer Communications, 2017
LTE Small cells like Femto cells are being deployed in enterprises and residential buildings to improve data rates of indoor users who experience low Signal-to-Interference plus Noise Ratio (SINR) from Macro Base Stations (MBSs). Deployment of Femto cells inside a building can lead to signal leakage at the edges/corners of the buildings. This causes cross-tier interference and degrades the performance of users in High Interference Zone (HIZone) around the building area, who are connected to one of the MBSs in LTE Heterogeneous Networks (HetNets). Hybrid Access Femto cells (HAFs) can ensure QoS for paid Subscriber Group (SG) users by giving them preferential access to resource blocks over non-SG (NSG) users and also improve the throughput of LTE HetNet system by serving nearby NSG users. In this work, we address various challenges involved in deployment and operation of HAFs in indoor environments by proposing an Optimal Placement of Femto cell (OPF) model, a dynamic Bandwidth Allocation (BWA) mechanism for splitting resource blocks between SG and NSG users, a dynamic power control mechanism to mitigate co-tier and cross-tier interference in HetNets and an Enhanced Priority (EP) scheduling mechanism to give more priority to SG users over NSG users. During peak traffic load scenarios, HAFs may not be able to guarantee QoS of both indoor and HIZone users connected to them. As HAFs are primarily meant for indoor users, HAFs employ an Optimal Power Control (OPC) mechanism to tune their transmit powers so that HIZone users are offloaded to nearby MBSs. Since the OPC is a Mixed Integer Non-linear Programming (MINLP) problem, we put forth a Sub-Optimal Power Control (SOPC) mechanism. The SOPC mechanism boosts the throughput of MBSs by almost 62% over the traditional 3GPP proposed enhanced Inter-Cell Interference Coordination (eICIC) mechanism for 300 users in the HetNet system. Also, the proposed EP scheduling mechanism maintains Jain's fairness index of 0.99 for both SG and NSG users while providing a 40% higher per user throughput than that obtained with the legacy proportional fair and Priority Set schedulers.
LTE Femtocells: System Design and Performance Analysis
IEEE Journal on Selected Areas in Communications, 2000
In this paper we consider a heterogeneous LTE network where femto cells are randomly deployed in a macro network. Femto cells are modeled as closed cells, namely only group member UEs can be associated with the femto cells. We demonstrate that inter-cell interference may prevent reliable operations for non-member UEs that are in proximity of a closed cell, which thus experience outage. We show how some of the novel features introduced in the Rel-10 specifications of the LTE standard can be leveraged by a suitable intercell interference coordination scheme (ICIC), which relies upon resource partitioning among different nodes to reduce the intercell interference problem. Additional significant improvements can be achieved when the proposed ICIC scheme is associated to a simple yet effective autonomous power control algorithm, described in detail in the paper, and further gains are demonstrated for UEs employing interference cancellation of broadcast interfering signals. We finally propose an enhanced ICIC method, based on a tighter coordination between macro and femto nodes, whose significant performance improvements advocate for suitable updates to the future LTE specifications.