Adaptive muting ratio in enhanced Inter-Cell Interference Coordination for LTE-A systems (original) (raw)
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Macro- and femtocell interference mitigation in OFDMA wireless systems
2012 IEEE Global Communications Conference (GLOBECOM), 2012
We conceive an interference mitigation scheme, for twin-layer networks for protecting the macrocell-users, from the interference imposed by the femtocells as well as for mitigating the interference amongst femtocells. Femtocells are capable of finding the available sub-bands using cognitive radio techniques, where the lowest interference is observed by the nearby macrocell-users. A sub-channel allocation algorithm is developed with the aid of graph-theoretic approaches for optimizing the femtocell throughput in dense femtocells deployment scenarios. The femto-users are grouped into different clusters for suppressing the interference amongst them. Each cluster is assigned a unique sub-channel by using the classic cluster-coloring approach. Adaptive power allocation is performed among the femtocells for further enhancing the system throughput and the attainable performance is quantified.
Inter-cell Interference Management for 4G Cellular Networks with Macro-and Femtocell Coexistence
To meet high data-rate target and obtain best use of the valuable spectrum, the forthcoming cellular systems are designed to support universal frequency reuse (UFR) and deploy femtocells. However, actual implementations of UFR in cellular systems lead to unacceptable interference levels at cell-edge area. Inter-cell interference coordination (ICIC) is one of the key techniques to manage and mitigate the inter-cell interference (ICI) for the forthcoming wireless broadband systems. In this paper, three ICIC schemes for two-tier cellular networks are presented: the reuse-3, soft frequency reuse (SFR) and partial frequency reuse (PFR). The first scheme is much simpler than the last two schemes, which demand location information of each mobile user to carry out the power control and frequency allocation. Simulation results show that the deployment of femtocells not only significantly reduces the blocking rate, but greatly increases the system capacity and draws in the performance gap between cell center and cell-edge users. It is also found that as the femtocells are deployed, the capacity of the reuse-3 method becomes comparable with the other two schemes (SFR and PFR). This indicates the usability of the simple reuse-3 method under the femtocell deployment without demanding the location information of mobile users which is much expensive to implement especially for smaller cells and high mobility users.
POSSIBLE SOLUTIONS FOR INTERFERENCE COORDINATION IN HETNETS OF LTE-A
IAEME PUBLICATION, 2021
In recent advances in cellular communication, the concept of heterogeneous networks has gained significant importance. A heterogeneous network is poised of multiple radio access technologies, architectures, transmission solutions, and base stations of varying transmission power that can interoperate, thus creating a multilayer structure. Management of interferences caused by the macro station to the low power nodes and vice versa is one of the biggest challenges in the deployment of heterogeneous networks. This paper presents a study of the mutual interference between a Macro cell and a Pico cell within LTE-A (Long Term Evolution – Advanced) framework. It is assumed that the Macro cell and the Pico cell share the same frequency channel and only the downlink (DL) performance is studied. In this paper, the possible solutions of enhanced inter-cell interference coordination (eICIC) in terms of throughput and power are analyzed.
Co-channel interference avoidance in two-tier LTE femtocell systems using control information
2013 19th Asia-Pacific Conference on Communications (APCC), 2013
Macrocell Base stations, called the Enhanced NodeB (eNB) are mainly aiming to serve outdoor users. However, due to insufficient signal strength this solution has difficulty in serving indoor users. To address this problem, the Femtocell, called the Home eNB(HeNB), system has been deployed in the L TE system. Since the HeNBs and the eNB use the same frequency band and the same frame structure, co-channel interference between HeNBs and eNB is unavoidable. To solve this problem, we propose a co-channel interference (CCI) avoidance scheme using the control information in the downlink subframe. Simulation results show the proposed scheme outperforms the conventional two-tier L TE femtocell systems in terms of the outage probability and the system throughput.
Interference management in OFDMA femtocell networks: issues and approaches
IEEE Wireless Communications, 2000
One of the effective techniques of improving the coverage and enhancing the capacity and data rate in cellular wireless networks is to reduce the cell size (i.e., cell splitting) and transmission distances. Therefore, the concept of deploying femtocells over macrocell has recently attracted growing interests in academia, industry, and standardization forums. Various technical challenges towards mass deployment of femtocells have been addressed in recent literature. Interference mitigation between neighboring femtocells and between the femtocell and macrocell is considered to be one of the major challenges in femtocell networks because femtocells share the same licensed frequency spectrum with macrocell. Further, the conventional radio resource management techniques for hierarchical cellular system is not suitable for femtocell networks since the position of the femtocells is random depending on the users' service requirement. In this article, we provide a survey on the different state-of-the-art approaches for interference and resource management in orthogonal frequency-division multiple access (OFDMA)-based femtocell networks. A qualitative comparison among the different approaches is provided. To this end, open challenges in designing interference management schemes for OFDMA femtocell networks are discussed.
An interference mitigation scheme for LTE based femtocell networks
2016
Femtocells are fully customized deployed base stations. They are being deployed in the macrocell cellular network in order to improve the indoor coverage and provide better user experience. Nevertheless, the randomly deployed femtocell poses a number of challenges, among the most critical is the interference as the achievable data rates and capacity depends mainly on the interference mitigation by the femtocell network. In this study, a self organizing solution combined with power control mechanism is proposed as the interference mitigation scheme for Long Term Evolution (LTE) femtocell network. The notion is based on adjusting the femtocell's transmission power and based on interference power received at femtocell downlink, in order to reduce the interference between femtocells. The power adjustment is controlled and based on some basic factors such as number of femtocells and distance between the femtocells and subscribers. The performance evaluation of real time services is conducted in terms of Packet Loss Ratio (PLR) and throughput.
2016
Femtocells are seen to be the future of Long Term Evaluation (LTE) networks to improve the performance of indoor, outdoor and cell edge User Equipments (UEs). These small cells work efficiently in areas that suffer from high penetration loss and path-loss to improve the coverage area. It is said that 30% of total served UEs in LTE networks are vehicular, which poses challenges in LTE networks due to their high mobility, high vehicular penetration loss (VPL), high path loss and high interference. Therefore, self-optimising and dynamic solutions are required to incorporate more intelligence into the current standard of LTE system. This makes the network more adaptive, able to handle peak data demands and cope with the increasing capacity for vehicular UEs. This research has drawn a performance comparison between vehicular UEs who are served by Mobile-Femto, Fixed-Femto and eNB under different VPL scales that range between highs and lows e.g. 0dB, 25dB and 40dB. Deploying Mobile-Femto ...
Interference avoidance with dynamic inter-cell coordination for downlink LTE system
2009
The investigation of co-channel interference mitigation techniques (such as, interference cancellation through receiver processing, interference randomization by frequency hopping, and interference avoidance through resource usage restrictions imposed by frequency and power planning) has become a key focus area in achieving dense spectrum reuse in next generation cellular systems such as 3GPP LTE, LTEadvanced, and WiMAX. In this paper, we propose an interference avoidance scheme for LTE downlink that uses dynamic inter-cell coordination facilitated through X2 interface among neighbouring evolved UTRAN nodeBs (eNBs, i.e., LTE base stations). Proposed scheme is evaluated by extensive simulations and compared with a number of reference schemes available in the literature. It has been observed that the proposed scheme attains superior performance in terms of cell-edge and sector throughput compared to those in the reference schemes.
Cognitive Interference Management in Heterogeneous Femto-Macro Cell Networks
2011 IEEE International Conference on Communications (ICC), 2011
In this work, we propose a cognitive interference management scheme for heterogeneous cellular wireless networks (LTE-A and WiMAX) with macrocells and femtocells (that operate in a closed-access mode). The scheme presented allocates resources (in time and frequency) and transmission opportunities to the macro/femtocells in the network by considering their potential to cause interference at each others associated user equipments (UEs). We study the efficacy of the proposed scheme using a LTE-A system level simulator and compare with frequency reuse techniques and no interference management scenarios. We observe that our scheme significantly enhances average cell-edge UE throughput (5%-tile throughput) with slight degradation in overall sum throughput. Also we observe that the scheme decreases the probability of cell-edge users in the system experiencing degraded SINR.
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.