Femtocell Research Papers - Academia.edu (original) (raw)

Nowadays the quality of the indoor coverage on trains is not enough to offer broadband services, mainly due to two factors: the high penetration losses caused by Faraday cage characteristics of the railcars and the high speeds reached. In this paper we aim to enhance the 3G indoor coverage on trains by setting up femtocells inside the railcars and establishing several wireless interfaces along the roof of the train. We design an architecture to connect the train to the fixed network in a transparent manner, so that the end users do not experience service disruptions during the journey. Finally, we deploy a testbed to evaluate the performance of the mobility management system based on test results.

- by
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- Femtocell, Mobile Femtocell, Multihomed Femtocell, Mobike
- by Harth Alhmam
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- Wireless Communications, Handover, Femtocell, Throughput
- by AHMED ALEESA
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- Information Security, Network Security, Security, Computer Security
- by Maysam Mirahmadi
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- Femtocell
- by Faisal Tariq
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- Mobile Computing, Cognitive radio, OFDM, Femtocell
- by Xiaoli Chu
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- Computer Architecture, Distributed Computing, Resource Allocation, Femtocell
- by Xiaoli Chu
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- Integer Programming, Resource Allocation, Convex Optimization, Femtocell
- by Mahamod Ismail
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- Algorithms, Wireless Communications, Resource Allocation, Femtocell

Future of cellular networks lies in heterogeneity. Heterogeneous cellular networks are characterized by overlay of low power nodes such as microcells, picocells, and femtocells along with traditional macrocell base stations. These nodes help operators to improve system capacity in cost effective manner while making the environment greener by reducing the carbon footprint. Research has shown that femtocells can be an effective solution to handle the increasing demands for indoor mobile traffic. However, low utilization of femtocell resources limits the gain obtained from their large scale deployment. Also, random placement of femtocells accumulate additional interference to macrocell users. In this paper, we introduce the concept of cell biasing for femtocells to improve user association and resource utilization. Our work analyses the effects of cell biasing on femtocell based cellular network and provides improvement in capacity and energy efficiency of the network through frequency...

- by Rahul Thakur and +1
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- Wireless Communications, Energy efficiency, Performance Evaluation, Femtocell
- by Nikos Dimitriou
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- Radio Resource Management, Femtocell, Power Control, Cellular Network

In LTE-A (LTE-Advanced), the access network cell formation is an integrated form of outdoor unit and indoor unit. With the indoor unit extension the access network becomes heterogeneous (HetNet). HetNet is a straightforward way to provide quality of service (QoS) in terms better network coverage and high data rate. Although, due to uncoordinated, densely deployed small cells large interference may occur, particularly in case of operating small cells within the spectrum of macro base stations (MBS). This paper probes the impact of small cell on the outage probability and the average network throughput enhancement. The positions of the small cells are retained random and modelled with homogeneous Poisson Point Process (PPP) and Matérn Cluster process (MCP). The paper provides an analytic form which permits to compute the outage probability, including the mostly applied fast fading channel types. Furthermore, simulations are evaluated in order to calculate the average network throughput for both random processes. Simulation results highlights that the network throughput remarkably grows due to small cell deployment.

- by Joydev Ghosh
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- Wireless Communications, Cognitive Radio Networks, Femtocell, NOMA and 5G
- by Hadi Otrok
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- Game Theory, Radio Resource Management, Genetic Algorithm, Femtocell

Efficient power and subchannel allocation methods are required for orthogonal frequency division multiple access (OFDMA) based femtocell networks to improve the capacity of the system. This paper considers a joint subchannel and power allocation algorithm with capacity maximization for downlink of an OFDMA based femtocell networks. In the proposed algorithm subchannel allocation is first performed based on signal to interference plus noise ratio (SINR) of the channel with equal power distribution. Then for enhancing capacity with optimal power allocation, successive convex approximation (SCA) based power optimization is adopted. The effect of Arithmetic geometric mean (AGM) approximation with SCA on power optimization is also investigated. The optimal power is subsequently distributed by water-filling algorithm.

- by Leonardo Gonsioroski
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- Femtocell, Channel Characterization

Mobile networks are the largest contributor
to the carbon footprint of the telecom sector and
their contribution is expected to rapidly increase in
the future due to the foreseen traffic growth. Therefore,
there is an increasing urgency in the definition
of green mobile network deployment strategies. This
paper proposes a four-step design and power assessment
methodology for mobile networks, taking into
consideration both radio and transport segments. A
number of mobile network deployment architectures
for urban residential areas based on different radio
(i.e., macro base station, distributed indoor radio,
femto cell) and transport (i.e., microwave, copper,
optical fiber) technologies are proposed and evaluated
to identify the most energy efficient solution. The
results show that with low traffic the conventional
macro base station deployment with microwave based
backhaul is the best option. However, with higher traf-
fic values heterogeneous networks with macro base
stations and indoor small cells are more energy effi-
cient. The best small cell solution highly depends on
the transport network architecture. In particular, our
results show that a femto cell based deployment with
optical fiber backhaul is the most energy efficient,
even if a distributed indoor radio architecture (DRA)
deployment with fiber fronthaul is also a competitive
approach.

- by Matteo Fiorani and +2
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- Heterogeneous Networks, Energy efficiency, Femtocell, Backhaul

Abstract We address the femtocell clustering together with the resource allocation in macro-femtocell networks. The clustering schemes allow the implementation of distributed approaches that can run locally within each cluster. Nevertheless, several limitations should be addressed for dense femtocell deployment, such as: lack of clustering schemes that encourage femtocells to grant service to public users and to become cluster members while guaranteeing their subscriber satisfaction, inefficient bandwidth usage due to the lack of bandwidth adaptation per tier when the cluster configuration changes, and lack of power control mechanisms to reduce interference. In this paper, we propose a distributed clustering model based on a cooperative game, where femtocells are encouraged to cooperate by forming clusters and rewarded with resources from macrocell. Our solution consists of: a cluster formation based on a coalitional game among femtocells and the macrocell to determine the subcarrier distribution per tier, a base station selection for public users and a resource allocation algorithm using Particle Swarm Optimization. We compare our solution with a centralized clustering approach and our cooperative clustering model using the well-known Weighted Water Filling resource allocation algorithm. Simulation results show that our proposal obtains throughput values similar to the centralized approach, satisfies the service requirements for both types of users and reduces the interference in comparison with the benchmark models.

- by Rebeca Estrada
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- Engineering, Computer Science, Technology, Computer Networks

Obtaining large spectral efficiency (SE) and energy efficiency (EE) subject to quality of experience (QoE) is one of the prime concerns for the wireless next generation networks, however a major confrontation with its trade-off which is becoming apparent while optimizing both SE and EE parameters concurrently. In this work, an analytical framework for a cognitive-femtocell network is proposed to be dealt with and overcome the situations regarded as unwelcome. Here, the conflict of SE-EE trade-off in downlink (DL) transmission is expressed methodically by Pareto Optimal Set (POS) based on a multi-empirical most effective use of a resource scheme as a function of femto base station (FBS) and macro base station (MBS) transmit power and base station (BS) density, respectively. Then, SE and EE are formulated in a utility function by applying Cobb-Douglas production function to transform the multi-empirical difficulty into the single-empirical optimization case. Besides, it is analytically shown that the SE-EE trade-off can be optimize through a distinctive universal optimum among the Pareto optimal by fine-tuning the weighting metric other than BS transmit power and density, respectively. Simulation results validate that it is possible to obtain the EE-SE trade-off with SINR threshold at different weighting factor.

- by Joydev Ghosh
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- Femtocell, 5G, Energy Efficiency, Spectral Efficiency
- by Xiaoli Chu
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- Game Theory, Femtocell

In this paper, we study interference mitigation in cellular networks with femtocells. We propose to use adaptive distributed beamforming to mitigate downlink interference between the femtocell users, known as Home User Equipments (HUEs), and macrocell users, known as Macrocell User Equipments (MUEs). We propose three beamforming schemes that consider the QoS requirement of the MUE and HUE, respectively, which provide much more flexibility in resource provisioning and signaling
requirement. The QoS requirement can be controlled by a
threshold that determines the choice of the beamforming
weight index. The proposed schemes minimize the interference
at the MUE or maximize the throughput at the HUE depending on the network traffic and QoS constraints. We also analyze the MUE mean throughput by applying order statistics theory.

- by Erchin Serpedin
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- Mobility, Femtocell, Fading, Interference

Today, most cyber-physical systems (CPS) in smart buildings require a wireless-based network infrastructure for sensing, communication , and actuation. In such CPSs, the energy expenditure and hence battery lifetime of the wireless network infrastructure depend heavily upon the placement of the base stations (BS). However, in indoor environments , BS placement is particularly challenging due to the impact of building structures and floors/walls separations. In this paper, we study the problem of jointly optimizing BS placement and power control in buildings to prolong the battery lifetime of sensors in the CPS network infrastructure. We first show that the joint BS placement and power control problem can be formulated as a mixed-integer non-convex program (MINCP), which is NP-hard and difficult to solve especially when the network size is large. To address this difficulty, we propose a novel efficient algorithm called ECPC that targets at large-sized network in-frastructures in buildings. Our theoretical analysis and numerical results show that ECPC achieves competitive solutions compared to the true optimal solutions obtained by the branch-and-bound method.

- by TK KOU
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- Wireless Communications, Mobile Computing, Green Building, Femtocell

Femtocell networks are a common means of offloading in current mobile networks. Game theoretic and learning-based self-organization schemes are known as two viable approaches for interference control in co-existing macro/femtocell networks. Nevertheless, extensions of these schemes to concurrent multi-agent scenarios often face several challenges including high computational complexity, cyclic behaviors, and lack of convergence. This paper addresses such challenges by introducing local games based on a graph representation of the network. The goal of the games is to optimize the aggregate network capacity through power control. Fairness among femtocells and quality of service (QoS) for macrocell users are also addressed. Finally, we prove that our algorithm converges to an equilibrium point.

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- by Enrico de Marinis
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- Genetics, Computer Science, Genetic Algorithms, Clustering Algorithms

In a conventional cellular network, UEs are connected directly to eNB, and when a vehicular UE moves away from the cell centre, it gets less bandwidth and lower data rates. However, Femtocells technology has been introduced in 3GPP to allow an indirect link between UEs and eNB through Femtocells. Femtocells can also be used to spread the cell coverage and increase coverage at areas with high path-loss and penetration loss. This paper focuses on the mobility management in LTE and Mobile Femtocells networks in order to mitigate the outage, dropping calls and blocking calls probabilities. The achieved results via MATLAB system level simulator have shown the advantages of implementing Mobile-Femtos over the Fixed-Femtos in the LTE Macrocell in terms of the achieved throughput, outage probability, drop and block calls probability.

- by Rand Raheem
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- Computer Science, Computer Network, Femtocell

ABSTRACT In this paper, we consider the problem of resource allocation in two-tier networks taking into consideration nondense femtocell deployments. The following limitations can be remarked from the prior work in the field of resource allocation: (1) resources are underutilized due to the equal power distribution in macrocell, (2) access to public users in femtocells is restricted to avoid depriving own subscribers transmissions, and (3) degradation of signal-to-noise ratio due to noise effects has not been evaluated. To overcome these limitations, we propose a joint power and bandwidth allocation among two tiers together with base station selection using genetic algorithm. Our solution is able to: (1) maximize the overall system throughput, (2) find an appropriate serving base station for each user, and (3) bandwidth and power assigned to each user. Simulations were conducted and a comparison with a Weighted Water Filling algorithm is carried out.

- by Rebeca Estrada
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- Computer Science, Genetic Algorithms, Resource Allocation, Genetic Algorithm

A microstrip patch antenna for multiple LTE (long term evaluation) frequency bands for femtocell application is proposed in this paper. Distributed antenna solution (DAS) has been introduced in cellular network to achieve homogenous indoor coverage. Femtocell is the latest extension to these solutions. It is a smart solution to both coverage and capacity scales. Femtocell operation in LTE band is occupied by higher frequency bands. For multiband femtocell application, miniature antenna design is quite essential. The antenna proposed here is composed of basic monopole structure with two parasitic elements at both sides of the active element. A rectangular slot is introduced at the ground plane of the proposed antenna. The antenna is designed using ElnoS HK light CCL substrate material of relative permittivity of 9.4, dielectric loss-tangent of 0.003 and thickness of 3 mm. The S11response of the antenna is shown to have a bandwidth of 1.01 GHz starting from 1.79 GHz to 2.8 GHz. The ch...

This work presents the evaluation of the downlink (DL) performance of a dual-layer cellular networks by using energy efficiency (EE) metric, where femto base stations (FBSs), macro base stations (MBSs) and users (FUs) form independent spatial Poisson point processes (PPPs). The proposed network model is developed by considering number of antennas at each BS alongside a single antenna at each user with the use of the conventional spectrum re-utilization approach. Then, Coverage probability and EE expressions for the dual-layer cellular networks are exclusively derived analytically. It is also demonstrated that simulation results are almost in-line with the analytical one in the PPP-based model. While coverage probability deteriorates with less margin in the lower FBS density region compared to the scheme presented in [10] signalled not much turnaround of the network performance, EE in the lower and the upper FBS density regions are likely to remain between 6 × 10^{−3} to 9.2 × 10^{−3} Bits/Joule and 4.6 × 10^{ −3} to 7.1 × 10^{−3} Bits/Joule, respectively. Proposed scheme tells us that it is firmly on course to match up with Vehicular Ad-hoc NETworks (VANET) applications without incurring high cost as EE, low latency, coverage probability and low power adaptability are back on good growth path.

- by Joydev Ghosh
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- Wireless Communications, Femtocell, 5G, Energy Efficiency

In this work, we present the cell edge coverage probability (CECP) performance of cellular networks under the composite multi-path fading environment, where Rayleigh fading is superimposed on log-normal shadowing, by the fractional frequency reuse (FFR) scheme. We demonstrate that our analytical results and the simulation results are in line with the analysis presented in [12].

- by Joydev Ghosh
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- Wireless Communications, Cognitive Radio Networks, Femtocell, NOMA and 5G
- by Rohayanti Hassan
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- Communication Technology, Femtocell, Link analysis, Throughput
- by Hadi Otrok
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- Game Theory, Radio Resource Management, Genetic Algorithm, Femtocell
- by Deepak Kataria
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- Wireless Communications, Femtocell
- by DAN HU
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- Computer Science, Distributed Computing, Resource Allocation, Femtocell

Next-generation wireless networks are going to have highly dense, small cell structure with a large number of femtocells. The dense deployment of the femtocell network architecture is expected to meet the growing data demand by leveraging millimeter-wave structure of 5G wireless networks. However, arbitrary deployment of large number of femtocells underlying a macrocell will pose a challenge for collision and confusion-free Physical Cell ID (PCID) assignments as the total number of available PCIDs is limited to 504. In this paper we propose a distributed, randomized kkk -clustering algorithm for collision and confusion-free PCID assignment problem, which is known to be NP-complete. To reduce the total control message flow, we create overlapping clusters in ultra-dense femtocellular networks, where each cluster head runs the distributed randomized PCID allocation algorithm and locally monitors the conflicts to avoid the collision and confusion constraints. We prove the correctness of our proposed algorithm and analyze its time and message complexity. Through simulation experiments, we also show the effect of different parameters on the PCID allocation objectives.

This paper investigates the concept of Mobile Femtocell with considering the feasibility of deploying Mobile Femtocells in public transportation vehicles such as trains, buses or private cars that form its own cell inside vehicles to serve vehicular and mobile User Equipments. This study is the launch of cell-edge mobile users who have always suffered degradation in the Quality of Service (QoS). Therefore, an investigation on the performance of LTE cell-edge mobile User Equipment e.g. users’ throughput, SINR, SNR, SIR, spectral efficiency and Handover performance, have been considered with deploying Fixed Femtocells and Mobile Femtocells in Long Term Evolution network. Two scenarios have been proposed in this study; Fixed Femtocells with mobile users and Mobile Femtocells with mobile users. More scenarios maybe considered in the case of Mobile Femtocell’s handover procedure. MATLAB simulation has been used for the purpose of simulating the designed scenarios and implementing the int...

- by Rand Raheem
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- Engineering, Computer Science, Computer Network, Femtocell
- by Rand Raheem
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- Computer Science, Computer Network, Femtocell

Universal mobile networks require enhanced capability and appropriate quality of service (QoS) and experience (QoE). To achieve this, Long Term Evolution (LTE) system operators have intensively deployed femtocells (HeNBs) along with macrocells (eNBs) to offer user equipment (UE) with optimal capacity coverage and best quality of service. To achieve the requirement of QoS in the handover stage among macrocells and femtocells we need a seamless cell selection mechanism. Cell selection requirements are considered a difficult task in femtocell-based networks and effective cell selection procedures are essential to reduce the ping-pong phenomenon and to minimize needless handovers. In this study, we propose a seamless cell selection scheme for macrocell-femtocell LTE systems, based on the Q-learning environment. A novel cell selection mechanism is proposed for high-density femtocell network topologies to evaluate the target base station in the handover stage. We used the LTE-Sim simulator to implement and evaluate the cell selection procedures. The simulation results were encouraging: a decrease in the control signaling rate and packet loss ratio were observed and at the same time the system throughput was increased.

- by Raed Abdulla
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- Handover, LTE, Femtocell, Cell selection

The integration of optical and wireless technologies at access networks are considered as a future solution which provide both high bandwidth and high mobility in an efficient way. GPON is a suitable candidate for optical backhaul due to the combination of higher data rates, greater split ratio and support for triple play services hence it offers maximum flexibility and cost advantages. On the other hand, recent developments of new radio access technologies and introduction of femtocell base stations provide the potential of offering broadband services and applications to everyone and everywhere. However, the power consumption of this network demands a particular attention because access networks are the largest contributor the network related electricity consumption. Therefore, in this paper we evaluate the power consumption of integrated optical-wireless access network which is based on independent ONU-BS architecture. We proposed a power consumption model for such network and the assessment has been done under different simulation scenarios. The constructed model will provide insight of the energy performance of the integrated access network so that in the network design process, focus can be done to the most energy saving strategies.

- by International Journal of Electrical and Computer Engineering (IJECE) and +1
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- Wireless Communications, Femtocell, Wireless access, GPON

An interference tolerant OFDMA scheme is proposed for multiuser wireless communications with specific application in femto cells. An interleaved set of subcarriers is dedicated to each user to provide with a high order of frequency diversity. A reduced complexity digital implementation of the technique is proposed and discussed for the interleaved sub-carrier arrangement. Both inter-symbol interference and other-user interference are mitigated using a proper cyclic extension, provided that the relative propagation delays of the users are an integer multiple of a symbol period. The effect of other-user interference due to non-integer propagation delays is investigated using computer simulations. The bit error rate performance and signal to interference ratio are presented for a few example systems over both an Additive White Gaussian Noise (AWGN) and a frequency selective Rayleigh fading channel. The amount of other-user interference is shown to be reduced as the number of sub-carriers per user is increased. The effect of design parameters on the interference level is discussed.

This research work explores small cell densification as a key technique for next generation wireless network (NGWN). Small cell densification comprises space (i.e, dense deployment of femtocells) and spectrum (i.e., utilization of frequency band at large). The usage of femtocells not only improves the spectral efficiency (SE) of the Heterogeneous two-tier networks against conventional approach, but also it alleviates outage probability and enhances the achievable capacity. We yield an analytical framework to establish the density of the femto base station (FBS) to a monotonically increasing or decreasing function of distance or radius, respectively. This ensures the enhanced performance in spectrum sharing Orthogonal Frequency Division Multiple Access (OFDMA) femtocell network models. We also illustrate the influence of active Femto users (i.e., users in femtocells, and they are usually low mobility and located closer to the cell center with less fading), cluster size (i.e., a group of adjacent macrocells which use all of the systems frequency assignments) via simulation results.

- by Joydev Ghosh
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- Wireless Communications, Cognitive Radio Networks, Femtocell, NOMA and 5G

In this paper, we study joint power and subchannel allocation problem for OFDMA based femtocell networks with focus on uplink direction. We minimize the aggregate power of all Femto user equipments and maximize the total system energy efficiency while satisfying the minimum required rate of all users. An interference limit constraint is considered to protect the QoS of macrocells. The original problem is a mixed-integer non-convex optimization problem which is converted to a convex problem using the time-sharing concept. Three algorithms are proposed to provide a scheme to optimize the goal function while meeting the constraints. The complexity order of all algorithms was investigated and was compared to other alternative solutions. The analytic and simulation results have demonstrated that the proposed algorithms could achieve significant power saving and better energy efficiency compared to existing algorithms.

- by Meysam Masoudi and +2
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- Wireless Communications, Resource Allocation, Femtocell, LTE Optimization
- by Rahim Tafazolli
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- Complexity Theory, Resource Allocation, Femtocell, Color

This paper proposes distributed joint power and admission control algorithms for the management of interference in two-tier femtocell networks, where the newly-deployed femtocell users (FUEs) share the same frequency band with the existing macrocell users (MUEs) using code-division multiple access (CDMA). As the owner of the licensed radio spectrum, the MUEs possess strictly higher access priority over the FUEs; thus, their quality-of-service (QoS) performance, expressed in terms of the prescribed minimum signal-to-interference-plus-noise ratio (SINR), must be maintained at all times. For the lower-tier FUEs, we explicitly consider two different design objectives, namely, throughput-power tradeoff optimization and soft QoS provisioning. With an effective dynamic pricing scheme combined with admission control to indirectly manage the cross-tier interference, the proposed schemes lend themselves to distributed algorithms that mainly require local information to offer maximized net utility of individual users. The approach employed in this work is particularly attractive, especially in view of practical implementation under the limited backhaul network capacity available for femtocells. It is shown that the proposed algorithms robustly support all the prioritized MUEs with guaranteed QoS requirements whenever feasible, while allowing the FUEs to optimally exploit the remaining network capacity. The convergence of the developed solutions is rigorously analyzed, and extensive numerical results are presented to illustrate their potential advantages.

- by Duy Ngo
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- Distributed Computing, Distributed Algorithms, Femtocell, Dynamic Pricing

Femtocells can be used to improve the indoor coverage and bandwidth of 3G cellular networks in homes and buildings. They are designed to be placed in a fixed location. However, their use would also be interesting in mobile environments such as public transportation systems. This paper studies the mobility limitations at the layer 3 and suggests an approach to support mobility on femtocell networks. This solution employs the protocols already defined in the femtocell architecture, minimizing thus the impact on it.

- by Carlos García-rubio
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- Femtocell, Femtocell Mobility, Mobile Femtocell, Multihomed Femtocell

LTE Network is a high speed Network but as compare with other Networks there are places in Network where there is less coverage or no coverage. Therefore to provide services in those areas, there is need of a technology which can fill the gap. This is done with the help of
Femtocells. A Femtocell use a very low power of about 0.1
watt but as the number of Femtocells in an area increases its
transmission power also increases. We know that cellular
network are based on radio radiation and Femtocells are
deployed very near to human environment. Therefore, it is
very important to take special care while deploying
Femtoells.