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This paper proposes a modified bat algorithm for optimal resource allocation scheme in closed access femtocell networks. Bat algorithm is a new nature-inspired metaheuristic algorithm which is inspired by the behaviour of bats echolocation. The main objective of the proposed algorithm is to select the best combination of resource blocks for femto users so as to minimize the co- and cross-tier interference...
Vastly increasing capacity and coverage demand in communication networks accompanied by energy efficiency challenge is getting attraction in research topics. Phantom cells based heterogeneous networks (HetNets) is a new idea which proposed to fulfil these requirements in the next generation cellular networks. In this paper, the resource allocation problem in an orthogonal frequency-division multiple...
We formulate the resource allocation in the downlink of heterogeneous orthogonal frequency division multiple access (OFDMA) networks. Our primary objective is to maximize the system sum throughput subject to service and system constraints, including maximum transmit power, quality of service and per-user subchannel allocation. Due to the intercell interference, the corresponding optimization problem...
Femtocell networks provide a good opportunity to satisfy increasing user demand for high data rate services. One of the most important challenges in femtocell networks is interference which degrades the overall system throughput considerably. In order to successfully deploy a femtocell network, efficient resource allocation algorithms and interference mitigation techniques should be deployed. In this...
Fractional Frequency Reuse (FFR) has been adopted in current two-tier Heterogeneous Networks (HetNet) with femtocells deployed in the presence of an overlaid macrocell. This technology would effectively reduce the inter-cell interference (ICI), from both co-tier and cross-tier, and thus achieve higher system throughput. Cell partitioning is an important parameter in FFR scheme. In this article, a...
Rapid growth in data traffic necessitates a proportional growth and improvement in the capacity of cellular networks. A heterogeneous network in which macro cells are overlaid with small cells is a cost efficient and effective paradigm shift for increasing the network traffic capacity. Unplanned deployment of low power base stations with divergent power levels introduces new challenges in heterogeneous...
Cell coverage and network capacity are two major challenges for the evolving 4G cellular wireless communication networks. Hierarchical layering of cells with macro base stations coexisting with low-power base stations in a service area has been investigated as a promising technique for enhancing the coverage extension and reducing the transmit power consumption, which has emerged as a candidate for...
When the femtocell performs power control in order to reduce the interference level, this may degrade the SNR at the femto-user side if the transmitted power is reduced to large amount. Thus power control is not efficient and other methods such as spectrum splitting among the femtocells is not efficient too and waste recourses. Femtocells must have a new mechanism so that to manage interference and...
Mobile network traffic is expected to increase dramatically with the proliferation of smart and diverse wireless devices. Moreover, pervasive and complex services such as mobile cloud, device-to-device communications and mobile multimedia consumption will require higher bandwidth and better network coverage. Hence, more spectrum and capacity with small cells and self-organization of heterogeneous...
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...
Spectrum sensing in cognitive femtocells play an important role in detecting spectrum holes and to opportunistically use under-utilized frequency bands without causing harmful interference to macrocell users. In case of mass deployment of femtocells, interference management is essential to maximize the capacity and achievable data rates. In this paper, a novel algorithm is proposed, based on Lagrangian...
In this paper, we propose a fuzzy-based channel assignment and power setting (FCAP) scheme for OFDMA-based macro-femto systems to effectively mitigate the interference caused by the deployment of femto base stations (FBSs). The FCAP scheme is a distributed solution for the spectrum allocation and interference mitigation problems in the macro-femto systems. By using the fuzzy logics, it dynamically...
Femtocells are low power access points that can be deployed by the consumer indoors to alleviate cellular coverage problems, offload traffic from the cellular network and boost user data rates. To enable the widespread of femtocells coexisting with macrocells, smart interference management schemes are required. Interference management by frequency allocation is still a big challenge in hybrid macro/femto...
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...
The increase in mobile data usage is pushing broad-band operators towards deploying smaller cells (femtocells) and sophisticated access technologies such as OFDMA. The expected high density of deployment and uncoordinated operations of femtocells however, make interference management both critical and extremely challenging. Femtocells have to use the same access technology as traditional macrocells...
This paper represented research on transmission scheme mechanism in Multimedia Broadcast and Multicast Service (MBMS) Long Term Evolution based on femtocells area. In MBMS, there are 3 types of transmission scheme, namely Point to Point, Point to Multipoint and Single Frequency Network. The last transmission scheme can only be occurred in Multi-cell transmission which all base station transmit the...
Femtocells can offload the traffic of macrocells and satisfy the big high-data-rate wireless communication requirement of indoor users. Due to the large number of fmetocells deployed by users, a significant challenge this new access technology brings to us is coordinating the cross-tier interference. Much special attention has been paid to solve the problem. This paper presents a novel strategy to...
Deploying femtocells faces a major challenge of causing downlink interference to the existing macrocell. This paper proposes an intelligent spectrum sharing mechanism for a two-layer cellular network, which comprises macrocells and femtocells. Because users are scheduled to access the spectrum in time-domain according to their channel conditions, the usage of spectrum is predictable by tracing the...
This paper studies the cooperative interference control in a two-cell downlink OFDMA system, which can be modeled as an interfering broadcast channel. It is assumed that each cell can simultaneously access the same frequency band, which corresponds to a universal frequency-reuse in cellular systems. We study the joint power and subcarrier allocation over the two cells to maximize their sum throughput...
The concept of small cells such as femtocell has been regarded as a promising solution to achieve green communication and deal with the coverage hole and growth of traffic within macrocells. However, the unpredictable deployment pattern of such nodes makes static network planing impractical and the overlaying macrocell and femtocell tiers may suffer significant cross-tier interference from each other...
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