Heterogeneous and opportunistic wireless networks

Recent years have witnessed the evolution of a large plethora of wireless technologies with different characteristics, as a response of the operators' and users' needs in terms of an efficient and ubiquitous delivery of advanced multimedia services. The wireless segment of network infrastructure has penetrated in our lives, and wireless connectivity has now reached a state where it is considered to be an indispensable service as electricity or water supply. Wireless data networks grow increasingly complex as a multiplicity of wireless information terminals with sophisticated capabilities get embedded in the infrastructure. © 2012 Springer Milan. All Right Reserved

Could a structural damage mimic a Parkinson plus syndrome?

Corticobasal syndrome (CBS) is a progressive disease that includes a heterogeneous neuropathological spectrum. In the majority of cases, corticobasal degeneration (CBD) is the underlying disease. Clinical heterogeneity is reflected in the clinical presentation of the syndrome and consequently misdiagnosis is common. Our case is of interest because the symptoms, the poor response to L-dopa and the I123 Ioflupane CIT SPECT (DAT-SCAN) results were typical for CBD. However, the magnetic resonance imaging appearance suggested the possibility of a disease of vascular etiology. A 63-year-old woman presented in our outpatient clinic with symptoms of progressive clumsiness in the right arm when performing movements demanding fine motor skills, and mild speech difficulties. The brain magnetic resonance imaging (MRI) report described ischemic lesions in the left subcortical parietal areas, in the centrum semiovale, in periventricular white matter, cingulated gyrus bilaterally and moderate ventricle dilatation. A comprehensive neuropsychological study suggested mixed cortical and subcortical involvement. A DAT-SCAN examination showed a diminished dopamine transporter uptake in the left lenticular nucleus, suggesting parkinsonisn. For this patient, CBS-CBD was the most probable diagnosis, whereas vascular CBS was not excluded. This case report illustrates the low diagnostic sensitivity in predicting CBD and the overlap with other related neurodegenerative diseases. Finally, it demonstrates that in CBS, different underlying pathologies can be found at the same individual. © 2013 Versita Warsaw and Springer-Verlag Berlin Heidelberg

Technical advances in the design and deployment of future heterogeneous networks

The trend in wireless communications systems is the enhancement of the network infrastructure with the introduction of small cells, where a specific geographical area is served by low-range, low-power access points. The result is the creation of a heterogeneous topology where macrocells coexist with a variety of small-cell types. In this editorial article we briefly summarize the recent technical advances in the design and deployment of future heterogeneous networks addressed in the papers that compose this special issue. In particular the following aspects are considered: the design of interference and radio resource management algorithms, the analysis of the energy efficiency and power control issues in heterogeneous networks, the concept of coordination in small cell networks, key backhaul aspects of HetNets, deployment issues and overall management strategies. © 2015, Kliks et al

Distributed radio resource allocation schemes in OFDMA cellular networks

The paper focuses on OFDMA Subcarrier Allocation algorithms for multiple users in a multi-cell scenario. The algorithms are distributed and either exploit measured interference per subcarrier feedback for all subcarriers (DRA algorithm) or they limit this feedback to the best subcarriers (Minimum Feedback DRA algorithm). These algorithms will be also compared with a Random Allocation Algorithm that is combined with a Fractional Frequency Reuse pattern to show the related trade-offs between performance and complexity