Interference management and system optimisation for Femtocells technology in LTE and future 4G/5G networks

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 under high VPLs has improved the vehicular UE Ergodic capacity by 1% and 5% under 25dB and 40dB VPL respectively as compared to other eNB technologies. A noticeable improvement is also seen in signal strength, throughput and spectral efficiency. Furthermore, this research discusses the co-channel interference between the eNB and the Mobile-Femto as both share the same resources and bandwidth. This has created an interference issue from the downlink signals of each other to their UEs. There were no previous solutions that worked efficiently in cases where UEs and base stations are mobile. Therefore, this research has adapted an efficient frequency reuse scheme that worked dynamically over distance and achieved improved results in the signal strength and throughput of Macro and Mobile-Femto UE as compared to previous interference management schemes e.g. Fractional Frequency Reuse factor1 (NoFFR-3) and Fractional Frequency Reuse factor3 (FFR-3). Also, the achieved results show that implementing the proposed handover scheme together with the Mobile-Femto deployment has reduced the dropped calls probability by 7% and the blocked calls probability by 14% compared to the direct transmission from the eNB. Furthermore, the outage signal probabilities under different VPLs have been reduced by 1.8% and 2% when the VPLs are 25dB and 40dB respectively compared to other eNB technologies

Novel group handover mechanism for cooperative and coordinated mobile femtocells technology in railway environment

Recently, the Mobile Femto (MF) Technology has been debated in many research papers to be a promising solution that will dominate future networks. This small cell technology plays a major role in supporting and maintaining network connectivity, enhancing the communication service as well as user experience for passengers in High-Speed Trains (HSTs) environments. Within the railway environment, there are many MF Technologies placed on HSTs to enhance the train passengers’ internet experience. Those users are more affected by the high penetration loss, path loss, dropped signals, and the unnecessary number of Handovers (HOs). Therefore, it is more appropriate to serve those mobile users by the in-train femtocell technology than being connected to the outside Access Points (APs) or Base Stations (BSs). Hence, having a series of MFs (called Cooperative and Coordinated MFs -CCMF) installed inside the train carriages has been seen to be a promising solution for train environments and future networks. The CCMF Technologies establish Backhaul (BH) links with the serving mother BS (DeNB). However, one of the main drawbacks in such an environment is the frequent and unnecessary number of HO procedures for the MFs and train passengers. Thus, this paper proposes an efficient Group HO mechanism that will improve signal connection and mitigate the impact of a signal outage when train carriages move from one serving cell to another. Unlike most work that uses Fixed Femtocell (FF) architecture, this work uses MF architecture. The achieved results via Matlab simulator show that the proposed HO scheme has achieved less outage probability of 0.055 when the distance between the MF and mobile users is less than 10 m compared to the signal outage probability of the conventional HO scheme. More results have shown that the dropping calls probability has been reduced when mobile users are connected to the MF compared to the direct transmission from the eNB. That is in turn has have improved the call duration of mobile UEs and reduced the dropping calls probability for mobile users who are connected to the MF compared to eNB direct connection UEs

Estimation of ransomware payments in Bitcoin ecosystem

Ransomware is one of the malicious software that is designed to prevent access to computer system until a sum of money is paid by the victim to the attacker. During the infection, the computer will either be locked, or the data will be encrypted. Ransoms are often demanded in Bitcoin, a largely anonymous Cryptocurrency. All transactions are recorded in the blockchain and verified by peer-to-peer networks. This paper investigation collects ten recent ransomware families, which use bitcoin as a payment for their ransom. In conjunction, we identified, collected and analysed Bitcoin addresses of users combining information from a clustering model and the blockchain. We used a heuristic clustering algorithm to reveal the hidden node's payment of ransomware. Finally, we demonstrated the characteristics of ransomware encryption mechanisms that include a view of the infected process and its execution, and the distinctive demands of ransom

Cooperative and coordinated Mobile Femtocells technology in high-speed vehicular environments: mobility and interference management

In future networks, most users who will be accessing wireless broadband will be vehicular. Serving those users cost-effectively and improving their signal quality has been the main concern of many studies. Thus, the deployment of Mobile Femtocell (Mobile-Femto) technology on public transportation is seen to be one of the promising solutions. Mobile-Femto comes with its mobility and interference challenges. Therefore, eliminating the Vehicular Penetration Loss (VPL) and interference while improving signal quality and mobility for train passengers is the main concern of this paper. The initial system-level evaluation showed that the dedicated Mobile-Femto deployment has great potential in improving users’ experience inside public transportation. The Downlink (DL) results of the Proposed Interference Management Scheme (PIMS) showed significant improvement in Mobile-Femto User Equipment (UE) gains (up to 50%) without impacting the performance of macro UEs. In contrast, the Uplink (UL) results showed noticeable gains for both macro UEs and Mobile-Femto UEs

Interference management for co-channel mobile femtocells technology in LTE networks

The dense deployment of Femtocells within the Macrocell's coverage is expected to dominate the future of Long Term Evolution (LTE) networks. While Mobile Femtocells (Mobile-Femtos) could be the solution for vehicular networks when there is a need to improve the vehicular User Equipment (UE) performance by mitigating the impact of penetration loss and path-loss issues. The deployed Femtocells have operated in a co-channel deployment due to the scarcity of spectrums. This issue causes interference between Femtocells and Macrocells as well it causes extra overhead on the LTE networks because of the co-tire interference between adjacent Femtocells. In this paper two interference scenarios are considered, the interference between Mobile-Femto and Macrocell, and the interference between the Mobile Femtos themselves. Therefore, to avoid the generated interference between Femtocells, the controlled transmission powers as well as the coverage planning techniques have been discussed. While in the worst-case scenarios, a frequency reuse scheme has been proposed to avoid the generated interference effectively and dynamically between the Mobile-Femtos as well as their UEs and between the Macrocell UEs

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

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

Mobile femtocell utilisation in LTE vehicular environment: vehicular penetration loss elimination and performance enhancement

Mobile computing is fast becoming a vital part of everyday life in which User Equipment (UE) demand being reachable anywhere and at anytime, as they spend much time travellingfrom one place to another, often by trains or buses. The ultimate aim of passengers is the ability to be connected to the Internet while they are moving from one place to another with their mobile devices. Providing indoor coverage on trains and buses directly with outdoor Base Stations (BSs) may not be a good solution due to the high density of use and path losses in the LTE network. This limitation can result in poor signal quality inside the train, and offering broadband services is not always possible. Clearly improvement to broadband access on buses and trains could be achieved by installing more BSs close to railway and bus routes and terminals. However, this solution is not ideal for the Internet Service Providers (ISPs) due to the high investment needed to deploy many more BSs. In addition, such a solution will introduce additional complexity by increasing the number of Handovers (HOs). This issue has focused the research community effort on developing solutions that take advantage of the existing wireless infrastructure without increasing the number of BSs. One method being considered is the development of more efficient methods and technologies to manage the UE’s mobility in seamless ways. In this paper we propose adoption of Mobile Femtocell (Mobile-Femto) technology as a solution to mitigate the Vehicular Penetration Loss (VPL) and Path Loss, with consequent improvement to the vehicular UE’s performance in LTE networks. Our results, using a Matlab simulation model, showed a noticeable improvement in the achieved Ergodic capacity by 5% under a VPL of 40dB while 90% of vehicular UEs spectral efficiency has improved by 1.3b/cu under a VPL of 25dB. In addition, 80% of vehicular UEs have improved their throughput and SINR by 300kb/s and 4dB respectively after implementing the Mobile-Femto into the Macrocell in LTE networks