Multi Radio Resource Management over WiMAX-WiFi Heterogeneous Networks: Performance Investigation

Mobile communication systems beyond the third generation will see the interconnection of heterogeneous radio access networks (WiMax, wireless local area networks, etc.) in order to always provide the best quality of service (QoS) to users with multimode terminals. This scenario poses a number of critical issues, which have to be faced in order to get the best from the integrated access network. In this paper, we investigate the issue of parallel transmission over multiple radio access technologies (RATs), focusing the attention on the QoS perceived by \ufb01nal users. Both the alternative and the parallel use of two RATs is considered. In particular, a scenario with a point of access providing both WiMAX and WiFi coverage will be investigated, and the performance level experienced by \u201cdual-mode users\u201d is assessed

Multiradio Resource Management: Parallel Transmission for Higher Throughput?

Mobile communication systems beyond the third generation will see the interconnection of heterogeneous radio access networks (UMTS, WiMax, wireless local area networks, etc.) in order to always provide the best quality of service (QoS) to users with multimode terminals. This scenario poses a number of critical issues, which have to be faced in order to get the best from the integrated access network. In this paper, we will investigate the issue of parallel transmission over multiple radio access technologies (RATs), focusing the attention on the QoS perceived by final users. We will show that the achievement of a real benefit from parallel transmission over multiple RATs is conditioned to the fulfilment of some requirements related to the kind of RATs, the multiradio resource management (MRRM) strategy, and the transport-level protocol behaviour. All these aspects will be carefully considered in our investigation, which will be carried out partly adopting an analytical approach and partly by means of simulations. In this paper, in particular, we will propose a simple but effective MRRM algorithm, whose performance will be investigated in IEEE802.11a-UMTS and IEEE802.11a-IEEE802.16e heterogeneous networks (adopted as case studies)

Mobile WiMAX Performance Investigation

Although the Mobile-WiMAX technology is being deployed in the United States, Europe, Japan, Korea, Taiwan and in the Mideast, there are still ongoing discussions about the potential of this technology. What is really remarkable, in fact, with regard to the Mobile-WiMAX profile, is the high number of degrees of freedom that are left to manufacturers. The final decision on a lot of very basic and crucial aspects, such as, just to cite few of them, the bandwidth, the frame duration, the duplexing scheme and the up/downlink traffic asymmetry, are left to implementers. It follows that the performance of this technology is not clear yet, even to network operators. This consideration motivated our work, which is focused on the derivation of an analytical framework that, starting from system parameters and implementation choices, allows to evaluate the performance level provided by this technology, carefully taking all aspects of IEEE802.16e into account. In particular, the analysis starts from the choices to be made at the physical layer, among those admitted by the specification, and "goes up" through the protocol pillar to finally express the application layer throughput and the number of supported voice over IP (VoIP) users, carefully considering "along the way" all characteristics of the the medium access control (MAC) layer, the resource allocation strategies, the overhead introduced, the inherent inefficiencies, etc

Distributed SPS Algorithms for Non-Asymptotic Confidence Region Evaluation

In this paper, the distributed computation of confidence regions for parameter estimation is considered. Some information diffusion strategies are proposed and compared in terms of the required number of data exchanges to get the corresponding region. The effects of algorithms truncation is also addressed. As support for the theoretical part, numerical results are presented

Energy and Spectrum Efficient Wireless Sensor Networks

1Department of Electrical, Electronic and Information Engineering, University of Bologna, Viale Risorgimento 2, 40136 Bologna, Italy 2Mathematical and Algorithmic Sciences Lab, France Research Center, Huawei Technologies Co. Ltd., 20 quai du Point du Jour, 92100 Boulogne-Billancourt, France 3Department of Information Engineering, University of Florence, Via di Santa Marta 3, 50139 Firenze, Italy 4BISITE Research Group, University of Salamanca, Edificio I+D+i, C/Espejo, 37007 Salamanca, Spain 5Department of Electronic Engineering, Tsinghua University, Beijing 100084, Chin

Smart city pilot projects using LoRa and IEEE802.15.4 technologies

Information and Communication Technologies (ICTs), through wireless communications and the Internet of Things (IoT) paradigm, are the enabling keys for transforming traditional cities into smart cities, since they provide the core infrastructure behind public utilities and services. However, to be effective, IoT-based services could require different technologies and network topologies, even when addressing the same urban scenario. In this paper, we highlight this aspect and present two smart city testbeds developed in Italy. The first one concerns a smart infrastructure for public lighting and relies on a heterogeneous network using the IEEE 802.15.4 short-range communication technology, whereas the second one addresses smart-building applications and is based on the LoRa low-rate, long-range communication technology. The smart lighting scenario is discussed providing the technical details and the economic benefits of a large-scale (around 3000 light poles) flexible and modular implementation of a public lighting infrastructure, while the smart-building testbed is investigated, through measurement campaigns and simulations, assessing the coverage and the performance of the LoRa technology in a real urban scenario. Results show that a proper parameter setting is needed to cover large urban areas while maintaining the airtime sufficiently low to keep packet losses at satisfactory levels

The Need of Multidisciplinary Approaches and Engineering Tools for the Development and Implementation of the Smart City Paradigm

This paper is motivated by the concept that the successful, effective, and sustainable implementation of the smart city paradigm requires a close cooperation among researchers with different, complementary interests and, in most cases, a multidisciplinary approach. It first briefly discusses how such a multidisciplinary methodology, transversal to various disciplines such as architecture, computer science, civil engineering, electrical, electronic and telecommunication engineering, social science and behavioral science, etc., can be successfully employed for the development of suitable modeling tools and real solutions of such sociotechnical systems. Then, the paper presents some pilot projects accomplished by the authors within the framework of some major European Union (EU) and national research programs, also involving the Bologna municipality and some of the key players of the smart city industry. Each project, characterized by different and complementary approaches/modeling tools, is illustrated along with the relevant contextualization and the advancements with respect to the state of the art

Selected Topics in WiMAX

In June 2001, operators and equipment vendors in the communications ecosystem founded the nonprofit WiMAX Forum, an industry-led organization aimed at harmonizing broadband wireless access standards, and certifying interoperability among devices from different manufacturers. Nowadays, about 10 years later, the WiMAX technology is a mature and affordable solution for high-speed IP-based 4G mobile broadband, fully supporting bandwidth-intensive services, such as high-speed Internet access and television, as well as less bandwidth-demanding but more latency-sensitive services, such as voice-over-IP calls. The deployment of WiMAX networks, which are based on the IEEE 802.16-2004 Air Interface Standard, started in many countries in 2005, as soon as manufacturers released the first equipments. The early WiMAX networks were aimed at providing fixed broadband wireless services in a wide geographical scale and proved to be a really effective solution for the establishment of wireless metropolitan area networks. On February 2006, the IEEE802.16e-2005 amendment gave a further extension to the potentialities of this technology, introducing a number of features aimed at supporting also users mobility; in this way, the so-called Mobile-WIMAX profile was born.. The result was a complete standard family that specified the air interface for both fixed and mobile broadband wireless access, enabling thus the convergence of fixed and mobile networks through a common wide area radio access technology. Since then, the interest in WiMAX increased dramatically; nowadays this technology is at work in more than 100 countries, providing both residential and mobile connectivity in urban areas as well as remote locations, due to the relatively low costs associated with its deployment (in comparison with 3G, HSDPA). The parallel development of the 4G Long Term Evolution (LTE) wireless access technology, currently deployed in many countries, is not expected to displace WiMAX, which had a first-mover advantage. It is likely, in fact, that the two technologies will be complementary. As LTE networks begin to roll out, it is extremely likely, for instance, that WiMAX will be used as the wireless backhaul for those networks, leaving to LTE the access provision. Moreover, WiMAX seems preferable for DSL replacement, especially in developing countries and rural regions, where wireline broadband technologies are not available. For these reasons, both the industrial and the scientific communities keep on developing and investigating WiMAX, with the final aim to get the best from this technology. In this book, a collection of selected papers is presented, which covers several aspects of the WiMAX technology, investigated by specialists working in universities and research centres all over the world. In particular, the book is organized following a bottom up structure, starting from link aspects up to the whole system. Chapter 1 is focused on multiuser (MU) multiple input multiple output (MIMO) diversity techniques. It provides a comprehensive overview of various MIMO strategies and a critical discussion on the recent research in multiuser MIMO communications with emphasis on the design of precoders. State-of-the-art in research on MU-MIMO precoding and multi-cell processing is presented. A new precoder design and its application in WiMAX setting is also provided. In chapter 2 the issue of the high peak-to-average power ratio (PAPR) that affects WiMAX is investigated, with particular reference to the adoption of companding as a PAPR mitigation strategy. Impairments from nonlinear distortion at the transmitter, multipath and noise are considered. Chapter 3 deals with the adoption of mesh architectures within WiMAX, and provides an overview of the main challenges of the WiMAX mesh mode, with a focus on routing protocols and the effect of quality of service mechanisms on scenarios with mobile clients. Chapter 4 investigates the handover mechanism, with particular reference to the cell selection scheme. A multi-criteria selection scheme is proposed, based on the experienced carrier-to-interference plus noise ratio, the required bandwidth and the expected congestion delay. In chapter 5 the issue of coordinated authentication in a heterogeneous network environment is investigated. A Coordinated Robust Authentication (CRA) Mechanism is presented, with the ability to use a single set of credentials with any network. Finally, Chapter 6 reviews the Multicast and Broadcast re-keying Algorithm (MBRA) of IEEE 802.16e, that ensures the confidentiality of communications. The operational efficiency, scalability and 1-affects-n phenomenon are discussed

Design, Deployment and Evolution of Heterogeneous Smart Public Lighting Systems

Street lighting characterizes many smart city initiatives around the world. In fact, significant savings can be achieved by not only replacing traditional luminaires with low-power LEDs, but also providing streetlights with smart light controllers and network connectivity, allowing the introduction of a sensible light intensity management and reduction of maintenance costs. Moreover, if designed with a far-looking view, smart lighting infrastructure could also support city-wide Internet of Things services, becoming key enablers of the smart city revolution, also in the 5G perspective. In this paper, we provide a thorough discussion on network architectures and communication technologies that could be adopted for smart public lighting applications, showing their benefits and downsides. Starting with significant activity on research, implementation and in-field testing, we also outline the steps required for the deployment of a smart public lighting infrastructure, each discussed in accordance with the network topology considered. Finally, we introduce some additional services that a smart public lighting infrastructure could support and discuss the benefits that would arise from integration with the upcoming 5G cellular network