A Robust Speed-Based Handover Algorithm for Dense Femtocell/Macrocell LTE-A Network and Beyond

Femtocells are currently being deployed in the present generation of cellular networks because of their ability to provide increased data rate at home and offices. This development together with the recent advances in technology brings about a huge increment in bandwidth required to meet the future demand for data by the ever increasing mobile devices. It is envisaged that with dense deployment of femtocells, the present challenge in terms of data requirement as well as the future demand will be met. Therefore, it is imperative to intensify the research in the area of handover management in femtocell/macrocell integrated network using a high dense network scenario that will dominate the future network. Presently, most research works in this area do not focus much on a dense deployment of mobile users in a femtocell/macrocell integrated network. Also, many existing handover algorithms were not designed to work in a highly mobile and dense environment. In this work, the authors propose a robust CAC handover algorithm for a dense femtocell/macrocell LTEAdvanced integrated network. The proposed CAC algorithm is efficient to handle calls in a highly dense and mobile user environment. The simulation results of the proposed algorithm show that the handover call dropping probability, call blocking probability and handover probability are considerably reduced

Femtocellular Aspects on UMTS Architecture Evolution

Recent advancement in System Architecture Evolution (SAE) has opened the door for the deployment of femtocells on a large scale. Deployment of femtocells in the existing macrocell networks and in 4G networks will significantly increase because femtocell offers increase coverage and capacity in both home and office environments. Hence it is likely that these low-power home based access points are going to change the landscape of mobile technology and the networking business in the coming years. This thesis work offers a deep insight into the mobile communication system architecture evolution and typically explains femtocellular aspects in the evolution of Universal Mobile Telecommunication System (UMTS) architecture. This research work mainly focuses on architectural variations of 3G and 4G femtocells along with the operational functionality of Local IP Access (LIPA). LIPA introduces the functionality in femtocells to access a home Local Area Network (LAN) and enable customers to use the Internet through Internet-enabled devices. Hence users have the capability to have simultaneous access to the operator's network as well as having access to their own home LAN. The way LIPA works is explained How it can create problems for femtocells deployment and what solutions LIPA offers for providing easy femtocell configurations. With the help of the extensive study about LIPA-enabled femtocells, different scenarios are discussed and two different solutions are proposed both for 3G and 4G femtocells. For maintaining higher data rates, 3G and 4G systems require a good coverage area to increase system performance. But research results suggest that two-thirds of consumers suffer from inadequate indoor signal penetration which actually leads to poor coverage for consumers, who do not enjoy the full data capacity as guaranteed. 4G systems will facilitate high speed data services, but poor coverage and interference will definitely diminish the quality of real-time applications and will significantly slow down high speed data services. The aim of this thesis is to propose di_erent logical indoor 4G femtocell architectures based on 3GPP specifications that will also be capable of providing LIPA functionality

Energy Efficiency Techniques & Challenges for Mobile Access Networks

Energy consumption of mobile access networks has recently received increased attention in research carried out in both industry and academia. The cellular networks do not have considerable share in the overall energy consumption of the ICT (Information and Communication Technology) sector. However, reduction in energy consumption of mobile networks is of great importance from economical (cost reduction) and environmental (decreased CO2 emissions) perspective. The Thesis work has investigated the different means to enhance the capacity of evolved mobile networks and discussed the related challenges from energy consumption perspective; this discussion is followed by a simple radio network power usage model. Based on the model examples are given where two different deployment scenarios have been compared. Further the work focused on the WCDMA energy saving through femtocell deployment. A simple model for the energy consumption per unit area has been derived based on WCDMA downlink load equations. Based on the model, two different deployment scenarios have been compared to make the conclusion from energy consumption perspective. In the end, the impact of femtocells to the energy efficiency of the WCDMA network has been studied under the consideration of a valuable power save feature of femtocell

Femtocell deployment; next generation in cellular systems

The final Bachelor’s Thesis that is shown below has such a final purpose of giving an overview of the inclusion of the so-called Femtocells (or Home Node B) in the current cellular systems. The main objective is to give a clear but simple idea about the concepts of Femtocells, as well as to explain the benefits and disadvantages of the mass uses of these services both for consumers and associated companies with this phenomenon. In this text it is also possible to find a brief review of wireless technologies throughout the history of telecommunications, as well as an introduction to the more current wireless technologies, with a special interest in the concept of cellular systems. In the last chapter a simple mathematical explanation of the key issue of interference between Femtocells and macrocellular networks is presented, with a brief argument about possible solutions

Energy efficiency in wireless communication

This era would probably be recognized as the information age, hence as a paramount milestone in the progress of mankind, by the future historians. One of the most significant achievements of this age is, making it possible to transmit and receive information effectively and reliably via wireless radio technology. The demand of wireless communication is increasing in a never-resting pace, imposing bigger challenge not only on service providers but also on innovators and researches to innovate out-of-the-box technologies. These challenges include faster data communication over seamless, reliable and cost effective wireless networks, utilizing the limited physical radio resources as well as considering the environmental impact caused by the increasing energy consumption. The ever-expanding wireless communication infrastructure is withdrawing higher energy than ever, raising the need for finding more efficient systems. The challenge of developing efficient wireless systems can be addressed on several levels, starting from device electronics, up to the network-level architecture and protocols. The anticipated gains of achieving such efficiency is the key feature of extending mobile devices' battery life and reducing environmental and economic impacts of wireless communication infrastructure. Therefore energy efficient designs are urgently needed from both environmental and economic aspects of wireless networks. In this research, we explore the field of energy efficiency in MAC and Physical layers of wireless networks in order to enhance the performance and reliability of future wireless networks as well as to reduce its environmental footprint. In the first part of this research, we analyse the energy efficiency of two mostly used modulation techniques, namely MQAM and MFSK, for short range wireless transmissions, up to a few $100$s of meters, and propose optimum rate adaptation to minimize the energy dissipation during transmissions. Energy consumed for transmitting the data over a distance to maintain a prescribed error probability together with the circuit energy have been considered in our work. We provide novel results for optimal rate adaptation for improved energy efficiency. Our results indicate that the energy efficiency can be significantly improved by performing optimal rate adaptation given the radio and channel parameters, and furthermore we identify the maximum distance where optimal rate adaptation can be performed beyond which the optimum rate then becomes the same as the minimum data rate. In the second part of this research, we propose energy efficient algorithm for cellular base stations. In cellular networks, the base stations are the most energy consuming parts, which consume approximately $60-80\%$ of the total energy. Hence control and optimization of energy consumption at base stations should be at the heart of any green radio engineering scheme. Sleep mode implementation in base stations has proven to be a very good approach for the energy efficiency of cellular BSs. Therefore, we have proposed a novel strategy for improving energy efficiency on ternary state transceivers for cellular BSs. We consider transceivers that are capable of switching between sleep, stand-by and active modes whenever required. We have modelled these ternary state transceivers as a three-state Markov model and have presented an algorithm based on Markov model to intelligently switch among the states of the transceivers based on the offered traffic whilst maintaining a prescribed minimum rate per user. We consider a typical macro BS with state changeable transceivers and our results show that it is possible to improve the energy efficiency of the BS by approximately $40\%$ using the proposed MDP based algorithm. In the third part of this research, we propose energy efficient algorithm for aerial base stations. Recently aerial base stations are investigated to provide wireless coverage to terrestrial radio terminals. The advantages of using aerial platforms in providing wireless coverage are many including larger coverage in remote areas, better line-of-sight conditions etc. Energy is a scarce resource for aerial base stations, hence the wise management of energy is quite beneficial for the aerial network. In this context, we study the means of reducing the total energy consumption by designing and implementing an energy efficient aerial base station. Sleep mode implementation in base stations (BSs) has proven to be a very good approach for improving the energy efficiency; therefore we propose a novel strategy for further improving energy efficiency by considering ternary state transceivers of aerial base stations. Using the three state model we propose a Markovian Decision process (MDP) based algorithm to switch between the states for improving the energy efficiency of the aerial base station. The MDP based approach intelligently switches between the states of the transceivers based on the offered traffic whilst maintaining a prescribed minimum channel rate per user. Our simulation results show that there is a around $40\%$ gain in the energy efficiency when using our proposed MDP algorithm together with the three-state transceiver model for the base station compared to the always active mode. We have also shown the energy-delay trade-off in order to design an efficient aerial base station. In the final part of our work, we propose a novel energy efficient handover algorithm, based on Markov decision process (MDP) for the two-tier LTE network, towards reducing power transmissions at the mobile terminal side. The proposed policy is LTE backward-compatible, as it can be employed by suitably adapting a prescribed SNR target and standard LTE measurements. Simulation results reveal that compared to the widely adopted policy based on strongest cell and another energy efficient policy, our proposed policy can greatly reduce the power consumption at the LTE mobile terminals. Most of our works presented in this dissertation has been published in conference proceeding and some of them are currently undergoing a review process for journals. These publications will be highlighted and identified at the end of the first chapter of this dissertation

Femtocell deployment; next generation in cellular systems

The final Bachelor’s Thesis that is shown below has such a final purpose of giving an overview of the inclusion of the so-called Femtocells (or Home Node B) in the current cellular systems. The main objective is to give a clear but simple idea about the concepts of Femtocells, as well as to explain the benefits and disadvantages of the mass uses of these services both for consumers and associated companies with this phenomenon. In this text it is also possible to find a brief review of wireless technologies throughout the history of telecommunications, as well as an introduction to the more current wireless technologies, with a special interest in the concept of cellular systems. In the last chapter a simple mathematical explanation of the key issue of interference between Femtocells and macrocellular networks is presented, with a brief argument about possible solutions

Femtocell Deployment; next generation in Cellular Systems

The final Bachelor's Thesis that is shown below has such a final purpose of giving an overview of the inclusion of the so-called Femtocells (or Home Node B) in the current cellular systems. The main objective is to give a clear but simple idea about the concepts of Femtocells, as well as to explain the benefits and disadvantages of the mass uses of these services both for consumers and associated companies with this phenomenon. In this text it is also possible to find a brief review of wireless technologies throughout the history of telecommunications, as well as an introduction to the more current wireless technologies, with a special interest in the concept of cellular systems. In the last chapter a simple mathematical explanation of the key issue of interference between Femtocells and macrocellular networks is presented, with a brief argument about possible solutions

Identification of femtocells in mobile networks

The evolving mobile networks are requested to convey increasing data traffic as popularity of online services together with affordability of mobile devices is growing. One solution to mobile carriers, which can help them quickly deploy small base stations (BS) ensuring great indoor coverage with minimum costs, and high data rate capability, is femtocell technology. However, standard deployment techniques are unsatisfactory for these type of BSs. There are two main reasons for that. Firstly, femtocells will be deployed in great numbers. Secondly, they are deployed by users and are portable. It means their position is not known in advance, and can vary in time. Therefore, femtocells have to implement self-configuration principles. Physical Cell Identity is one of the most important parameters to be chosen automatically under defined conditions. It is crucial parameter, which allows them to convey a communication between a user equipment and a core network. A study on Physical Cell Identity issues in mobile networks with femtocells is presented in my thesis. For this purpose, I created two different models of femtocells deployment and deal with a collision and a confusion. They are two main problems, which threaten proper Physical Cell Identity assignment in mobile networks. Outputs of the thesis serves for better understanding of interrelations between differently placed femtocells in term of collision and confusion issue and as the basis to design the framework handling Physical Cell Identity allocation. The simulations conducted on proposed models were utilized to obtain probability characteristics and indicators based on graph theory. In the evaluation section, I appoint several characteristics as probability of collision, probability of confusion and maximal number of neighbourhood cells and some others to support solution of collision and confusion issue. I use results of evaluation and layout the framework for automated Physical Cell Identity assignment with two different approaches, the distributed one, and the centralized one. Since, femtocells are subcategory of small cells so findings, mentioned in this thesis, can also be used for other types of small cells.Katedra telekomunikační technik