Hybrid Radio/Free-Space Optical Design for Next Generation Backhaul Systems

The deluge of date rate in today's networks imposes a cost burden on the backhaul network design. Developing cost efficient backhaul solutions becomes an exciting, yet challenging, problem. Traditional technologies for backhaul networks include either radio-frequency backhauls (RF) or optical fibers (OF). While RF is a cost-effective solution as compared to OF, it supports lower data rate requirements. Another promising backhaul solution is the free-space optics (FSO) as it offers both a high data rate and a relatively low cost. FSO, however, is sensitive to nature conditions, e.g., rain, fog, line-of-sight. This paper combines both RF and FSO advantages and proposes a hybrid RF/FSO backhaul solution. It considers the problem of minimizing the cost of the backhaul network by choosing either OF or hybrid RF/FSO backhaul links between the base-stations (BS) so as to satisfy data rate, connectivity, and reliability constraints. It shows that under a specified realistic assumption about the cost of OF and hybrid RF/FSO links, the problem is equivalent to a maximum weight clique problem, which can be solved with moderate complexity. Simulation results show that the proposed solution shows a close-to-optimal performance, especially for practical prices of the hybrid RF/FSO links

A NOVEL METHOD FOR THE CODECS’ PERFORMANCE ANALYSISIN MOBILE TELEPHONY SYSTEMS

This paper presents a novel method of expressing the quality of service in a mobile telecommunication system when its performance depends on several factors including applied codecs’ characteristics (voice quality and data flow rate) and telecommunications traffic service possibilities. The influence of these factors is unified in one variable - quality of service measure. The proposed method is especially applicable in the cases when two-dimensional systems are analyzed – for example when two codecs with different flow rate and different achievable connection quality are used in a system. As an example, we also studied system with full-rate or mixed full-rate and half-rate codec implementation depending on the offered traffic. The system performances – mean data-flow and mean connection quality as a function of offered traffic are presented graphically and also expressed quantitatively by the novel quality of service measure. The systems with different number of available traffic channels may be compared on the base of this novel evaluation value such that the system with the highest value is the most suitable one for the concrete situation. In this way mobile system design is simplified to the great extent. The developed model is applicable generally for mobile telephony systems defining, but in this paper we studied its implementation for Global System for Mobile communications

Introduction to the mobile application development with an example of a "PhraseBook app"

The aim of this project is to combine and apply the knowledge and experience obtained along this master degree and try to create a market opportunity by developing mobile applications for iPhone devices. The idea is not to become a full time mobile developer but perhaps a passive player with some income stream. I am well aware that the battle of mobile applications is brutal and some competitors are way beyond the rest, with great capital behind them and with excellent programing skills. Still the experience, the time invested along with hard work can only bring good results. This effort may not be reflected in an overnight minor fortune, but its about daring to compete, learn fast and adapt and show what your capable of. The project arises as a curiosity to discover how mobile app are created, what it takes to start building your own application, what do you need to know to develop one. My inclination to start testing on Apple’s iPhone is because I currently own a MacBook and an iPhone 4 device. I am familiar with the Mac environment and I have a preference for Apple’s software, I also find the iPhone operating system quite interesting and therefor I am curious to know what is behind its impressive performance. One of the most interesting things I find about this project is the set of skills you need to have to start creating applications. You should be able not only to program what your idea is about but also in designing what your idea is going to look like. A developer must create the code that is going to be the backbone of the application and also he must create all the graphic environment that is going to represent that code making it appealing for the user. When thinking about what you are going to build you should as well think about how it is going to be represented, like the colors, the orientation of the phone whether it is going to be landscape or portrait, the buttons, the tab bars, sounds, video, wether it is going to use internet connection or not. All this aspects have to be taken into account at the same time you are trying to figure how to write down all that you want your application to do. So you must combine your creativity and your technical skills to fulfill all that you want your application to do

Efficient cloud-based cellular planning algorithms for 3G and 4G networks

In mobile network deployments of growing size, the optimum and fast planning of radio resources are a key task. Cloud services enable efficient and scalable implementation of procedures and algorithms. In this dissertation, a cloud-based planning system for 3G and 4G networks is presented, using Amazon Web Services (AWS) for cloud implementation. It extracts configuration and performance data from the network, enabling to accurately estimate cells coverage, identify neighbouring cells and optimally plan Scrambling Codes (SC) in an UMTS network and Physical Cell Identity (PCI) in LTE networks. This system is integrated in a Software-as-a-Service monitoring and planning tool Metric, owned by Multivision, allowing for an easy and efficient allocation of the network resources. The system operation is demonstrated in a small canonical scenario for SCs, a small realistic scenario of PCIs cluster planning, taking less than 0,6 seconds to perform the planning. For a realistic 3G scenario with 12 484 unplanned cells, the planning of SCs is efficiently achieved, taking less than 8 seconds, and guaranteeing no collisions between first order neighbouring cells.Nas implementações de redes móveis grande escala, o planeamento otimizado e rápido dos recursos de rádio é uma tarefa fundamental. Os serviços em cloud permitem a implementação eficiente e escalável de padrões e algoritmos. Nesta dissertação, é apresentado um sistema de planeamento baseado em cloud para redes 3G e 4G, fazendo recurso à Amazon Web Services (AWS) para implementação em cloud. Este sistema extrai dados de configuração e desempenho da rede, o que permite estimar com precisão a cobertura das células, identificar células vizinhas e planear de forma eficiente os Scrambling Codes (SC) em redes UMTS e Physical Cell Identity (PCI) em redes LTE. Este sistema está integrado no Metric, uma ferramenta de planeamento e monitorização de Software-as-a-Service, propriedade da Multivision, permitindo uma alocação fácil e eficiente dos recursos da rede. A operação do sistema é demonstrada num pequeno cenário canónico para SCs, um pequeno cenário realista de um cluster de células pertencentes a uma rede LTE, onde se pretende planear os seus PCIs. O algoritmo executa um planeamento ótimo deste cluster em menos de 0,6 segundos. Para um cenário 3G realista com 12 484 células não planeadas, a alocação dos SCs é realizada com eficiência, levando menos de 8 segundos e garantindo que não existem colisões entre as células vizinhas de primeira ordem

On Performance Analysis of Single Frequency Network with C-RAN

Centralized-RAN (C-RAN) is an architectural trend that uses resource sharing and a set of interference mitigation techniques to reduce capital and operational expenditures for mobile network operators (MNOs). One of the technical enablers of a C-RAN solution is single frequency network (SFN) that curbs the interference and allows MNOs to transmit over single frequency across coordinated cells. One of the main advantages of SFN is that it reduces the number of handovers between neighboring cells while improving the overall system performance. In contrast to previous approaches that demonstrate some of the most prominent C-RAN features, in this paper, we first investigate two different SFN deployment scenarios’ characteristics, benefits, and limitations. Second, we perform a simulation analysis of non-SFN and SFN without joint scheduling to observe signal to interference ratio heatmap distribution of the experimental test-site using similar system configurations. Finally, we perform an experimental analysis of joint scheduling in SFN based on coordinated inter baseband units scenario using C-RAN in a realistic environment. The experimental results are tested on a real operating site of a major MNO’s infrastructure in Turkey. Through experimental results, we show overall performance gains of SFN feature in terms of different key performance indicators that are obtained from coordinating remote radio units in an SFN cell. Finally, we discuss about the main takeaways, lessons learned, and challenges of the considered SFN implementation