Nowadays most communication networks like GSM, WLan or WiMAX are based on pre-existing infrastructure. These infrastructures are complicated, costly and difficult to deploy in very short time. Whereas Wireless Ad Hoc Networks are infrastructure-free self organizing networks which consist of cooperating nodes. These networks are highly desirable for various emerging applications for military and...

Non-linear dynamic time history analysis is considered as the most advanced and comprehensive analytical method for evaluating the seismic response and performance of multi-degree-of-freedom building structures under the influence of earthquake ground motions. However, effective and accurate application of the method requires the implementation of advanced hysteretic constitutive models of the ...

A novel definition of a spread-spectrum signal as a signal whose Fourier bandwidth is much greater than its Shannon bandwith (one-half the number of dimensions of signal space required per second) is proposed. Six different communication systems are analyzed in terms of this definition. It is shown that there is a fundamental difference between the bandwidth expansion due to coding and that due...

Executive Summary Spectrum, the single most important resource for telecommunication voice and mobile broadband service, is finite and limited. As subscribers demand faster and increased capacity anytime, anywhere, operators face the challenge of maximizing all available spectrum assets – FDD or TDD. In previous 3GPP standards, mobile operators have deployed Frequency Division Duplex (FDD) tech...

In recent years, the mobile data usage has grown by 70–200 percent per annum. More worryingly, the bursty nature of wireless data traffic makes traditional network planning for capacity obsolete. Amongst both operators and vendors alike, small cells (e.g., picocells, femtocells and relay nodes) have been considered as a promising solution to improve local capacity in traffic hotspots, thus reli...

Throughput maximization is one of the main challenges in cognitive radio ad hoc networks, where the availability of local spectrum resources may change from time to time and hop-by-hop. For this reason, a cross-layer opportunistic spectrum access and dynamic routing algorithm for cognitive radio networks is proposed, called ROSA (ROuting and Spectrum Allocation algorithm). Through local control...

The set of 5G requirements show that future radio systems should answer to network capabilities in terms of : capacity, spectrum for future evolutions, fixed-mobile convergence, integration of 3GPP and and robustness, cost efficiency, etc. In parallel, new user experiences area, from static to high-speed-throughput per user/ application, E2E to the need of new enablers for business as: Internet...

In cognitive radio networks (CRNs), unlicensed users (secondary users – SUs) lease free spectrum with quality of service (QoS) guarantees from a multitude of spectrum owners (primary users, PUs) based on service level agreements (SLA). Free spectrum is used to establish the links of secondary network. The amount of leased spectrum influences the admitted number of SU’s requests, PUs’ profits, a...

Device-to-Device (D2D) communication, which enables direct communication between nearby mobile devices, is an attractive add-on component to improve spectrum efficiency and user experience by reusing licensed cellular spectrum. Nowadays, LTE-unlicensed (LTE-U) emerges to extend the cellular network to the unlicensed spectrum to alleviate the spectrum scarcity issue. In this paper, we propose to...

The coexistence of heterogeneous networks within the same spectrum for enhancing the spectrum efficiency has attracted large interest lately in the research community. Furthermore, the research interest towards the deployment of small cells and multibeam satellites is increasing due to high capacity, easier deployment and higher energy efficiency. However, due to the scarcity of available spect...