Mobile Networks

The growth in the use of mobile networks has come mainly with the third generation systems and voice traffic. With the current third generation and the arrival of the 4G, the number of mobile users in the world will exceed the number of landlines users. Audio and video streaming have had a significant increase, parallel to the requirements of bandwidth and quality of service demanded by those applications. Mobile networks require that the applications and protocols that have worked successfully in fixed networks can be used with the same level of quality in mobile scenarios. Until the third generation of mobile networks, the need to ensure reliable handovers was still an important issue. On the eve of a new generation of access networks (4G) and increased connectivity between networks of different characteristics commonly called hybrid (satellite, ad-hoc, sensors, wired, WIMAX, LAN, etc.), it is necessary to transfer mechanisms of mobility to future generations of networks. In order to achieve this, it is essential to carry out a comprehensive evaluation of the performance of current protocols and the diverse topologies to suit the new mobility conditions

From fixed to mobile femtocells in LTE systems: issues and challenges

This paper investigates the concept of Mobile Femtocell which is the extension of implementing Mobile Relays and Fixed Femtocells. Mobile Femtocells can be deployed 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 intends to help cell-edge users to have better signal strength. An investigation into Long Term Evolution cell-edge users' performance is being conducted by investigating the deployment of Mobile Femtocells in LTE system. The throughput for cell edge users can be improved by deploying Fixed/Mobile Femtocells. This paper is considering several scenarios namely; Fixed Femtocells with Fixed users, Mobile Femtocells with fixed users, Fixed Femtocells with mobile users and Finally Mobile Femtocells with mobile users. The achieved results via Matlab simulation showed that Mobile Femtocells' users have enjoyed better Quality of Services than Fixed Femtocells' users. The improved performance has been noticed through the improvement of the Mobile Femtocells UEs' spectral efficiency, throughput and SINR over the Fixed Femtocells' users

WLAN-UMTS integration to optimize MBMS provision

Provision of multimedia services with high bandwidth demands is constantly increasing its share in mobile systems. Aiming a more efficient distribution of multicast/broadcast contents in the UMTS networks, 3GPP introduced the Multimedia Broadcast Multicast Service (MBMS). Even though this technology brought significant improvements regarding the network efficiency, the UTRAN (UMTS Terrestrial Radio Access Network) remains the network’s most vulnerable area due to its shortage resources. The integration of wireless LAN (WLAN) access technology in cellular data networks to enhance their services coverage and increase data rates, is an extremely interesting solution for operators. In addition, this solution based on WLAN is easily deployed and can provide additional license-free bandwidth. Therefore, this paper addresses a possible WLAN integration, which uses a UMTS Access Point (UAP) that establishes a WLAN tunnel to provide MBMS data services to UEs with both UMTS and WLAN interfaces. Using this simulation environment, we pretend to measure and conclude about the benefits achieved from merging these two access technologies when delivering MBMS services.info:eu-repo/semantics/acceptedVersio

Performance evaluation of LTE network via using fixed/mobile femtocells

This paper examines the concept of Mobile Femtocells to be the revolution of the next generation cellular networks. Mobile Femtocells can be deployed 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. The purpose of this study is to help cell-edge users to have better signal strength. Therefore, an investigation into Long Term Evolution cell-edge users' performance is being conducted by investigating the deployment of Mobile Femtocells in LTE system. The throughput for cell edge users can be improved by deploying Fixed/Mobile Femtocells. In this paper, two scenarios have been considered in the case of Fixed/Mobile Femtocells. The handover of Mobile Femtocell has been expressed in three more scenarios. The achieved results via Matlab simulation showed that Mobile Femtocells' users have enjoyed better Quality of Services than Fixed Femtocells' users. The improved performance has been noticed through the improvement of the Mobile Femtocells UEs' spectral efficiency, throughput and SINR over the Fixed Femtocells' users. The system behavior has been investigated under low, medium and high load traffic before and after adding the Mobile Femtocells. The results showed that adding the Mobile Femtocells in the high loaded traffic areas has the biggest affect on improving the UE's throughput

Mobility management for vehicular user equipment in LTE/mobile femtocell networks

Vehicular User Equipment (UE) performance during mobility faces two issues relating to signaling and transmission, namely Handover (HO) and link adaptation. This paper shows that both processes are experiencing degradation during mobility and that vehicular UEs suffer from call drops and loss of connections. Therefore, this work presents an effective technique using Mobile-Femtos to improve vehicular UEs' HO process and link quality. Results show that vehicular UEs attached to a Mobile-Femto achieved better signalling and Link Ergodic capacity and as a consequence the outage probability was reduced. The achieved results indicated that deploying Mobile-Femtos under 25dB Vehicular Penetration Loss (VPL) has improved the vehicular UE Link Ergodic capacity by 1% and reduced the signal outage probability by 1.8% compared to the eNB direct transmission. Consequently, Drop Calls Probability (DCP) and Block Calls Probability (BCP) have been reduced by 7% and 14% respectively compared to the direct transmission from the eNB

Scalable RAN Virtualization in Multi-Tenant LTE-A Heterogeneous Networks (Extended version)

Cellular communications are evolving to facilitate the current and expected increasing needs of Quality of Service (QoS), high data rates and diversity of offered services. Towards this direction, Radio Access Network (RAN) virtualization aims at providing solutions of mapping virtual network elements onto radio resources of the existing physical network. This paper proposes the Resources nEgotiation for NEtwork Virtualization (RENEV) algorithm, suitable for application in Heterogeneous Networks (HetNets) in Long Term Evolution-Advanced (LTE-A) environments, consisting of a macro evolved NodeB (eNB) overlaid with small cells. By exploiting Radio Resource Management (RRM) principles, RENEV achieves slicing and on demand delivery of resources. Leveraging the multi-tenancy approach, radio resources are transferred in terms of physical radio Resource Blocks (RBs) among multiple heterogeneous base stations, interconnected via the X2 interface. The main target is to deal with traffic variations in geographical dimension. All signaling design considerations under the current Third Generation Partnership Project (3GPP) LTE-A architecture are also investigated. Analytical studies and simulation experiments are conducted to evaluate RENEV in terms of network's throughput as well as its additional signaling overhead. Moreover we show that RENEV can be applied independently on top of already proposed schemes for RAN virtualization to improve their performance. The results indicate that significant merits are achieved both from network's and users' perspective as well as that it is a scalable solution for different number of small cells.Comment: 40 pages (including Appendices), Accepted for publication in the IEEE Transactions on Vehicular Technolog

A Vertical Handover Algorithm in Integrated Macrocell Femtocell Networks

The explosion in wireless telecommunication technologies has lead to a huge increase in the number of mobile users. The greater dependency on the mobile devices has raised the user’s expectations to always remain best connected. In the process, the user is always desiring good signal strength even at certain black spots and indoors. Moreover, the exponential growth of the number of mobile devices has overloaded macrocells. Femtocells have emerged out as a good promising solution for complete coverage indoors and for offloading macrocell. Therefore, a new handover strategy between femtocells and macrocell is proposed in this paper. The proposed handover algorithm is mainly based on calculating equivalent received signal strength along with dynamic margin for performing handover. The simulation results of proposed algorithm are compared with the traditional algorithm. The proposed strategy shows improvement in two major performance parameters namely reduction in unnecessary handovers and Packet Loss Ratio. The quantitative analysis further shows 55.27% and 23.03% reduction in packet loss ratio and 61.85% and 36.78% reduction in unnecessary handovers at a speed of 120kmph and 30kmph respectively. Moreover, the proposed algorithm proves to be an efficient solution for both slow and fast moving vehicles

Performance evaluation of mobile users served by fixed and mobile femtocells in LTE networks

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 integrated mathematical equations. The simulated results have demonstrated the benefits of having Mobile Femtocells over the Fixed Femtocells in terms of mobile User Equipments’ performance

Radio network management in cognitive LTE-Femtocell Systems

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London.There is a strong uptake of femtocell deployment as small cell application platforms in the upcoming LTE networks. In such two-tier networks of LTEfemtocell base stations, a large portion of the assigned spectrum is used sporadically leading to underutilisation of valuable frequency resources. Novel spectrum access techniques are necessary to solve these current spectrum inefficiency problems. Therefore, spectrum management solutions should have the features to improve spectrum access in both temporal and spatial manner. Cognitive Radio (CR) with the Dynamic Spectrum Access (DSA) is considered to be the key technology in this research in order to increase the spectrum efficiency. This is an effective solution to allow a group of Secondary Users (SUs) to share the radio spectrum initially allocated to the Primary User (PUs) at no interference. The core aim of this thesis is to develop new cognitive LTE-femtocell systems that offer a 4G vision, to facilitate the radio network management in order to increase the network capacity and further improve spectrum access probabilities. In this thesis, a new spectrum management model for cognitive radio networks is considered to enable a seamless integration of multi-access technology with existing networks. This involves the design of efficient resource allocation algorithms that are able to respond to the rapid changes in the dynamic wireless environment and primary users activities. Throughout this thesis a variety of network upgraded functions are developed using application simulation scenarios. Therefore, the proposed algorithms, mechanisms, methods, and system models are not restricted in the considered networks, but rather have a wider applicability to be used in other technologies. This thesis mainly investigates three aspects of research issues relating to the efficient management of cognitive networks: First, novel spectrum resource management modules are proposed to maximise the spectrum access by rapidly detecting the available transmission opportunities. Secondly, a developed pilot power controlling algorithm is introduced to minimise the power consumption by considering mobile position and application requirements. Also, there is investigation on the impact of deploying different numbers of femtocell base stations in LTE domain to identify the optimum cell size for future networks. Finally, a novel call admission control mechanism for mobility management is proposed to support seamless handover between LTE and femtocell domains. This is performed by assigning high speed mobile users to the LTE system to avoid unnecessary handovers. The proposed solutions were examined by simulation and numerical analysis to show the strength of cognitive femtocell deployment for the required applications. The results show that the new system design based on cognitive radio configuration enable an efficient resource management in terms of spectrum allocation, adaptive pilot power control, and mobile handover. The proposed framework and algorithms offer a novel spectrum management for self organised LTE-femtocell architecture. Eventually, this research shows that certain architectures fulfilling spectrum management requirements are implementable in practice and display good performance in dynamic wireless environments which recommends the consideration of CR systems in LTE and femtocell networks