Spectral Efficiency of MIMO Millimeter-Wave Links with Single-Carrier Modulation for 5G Networks

Future wireless networks will extensively rely upon bandwidths centered on carrier frequencies larger than 10GHz. Indeed, recent research has shown that, despite the large path-loss, millimeter wave (mmWave) frequencies can be successfully exploited to transmit very large data-rates over short distances to slowly moving users. Due to hardware complexity and cost constraints, single-carrier modulation schemes, as opposed to the popular multi-carrier schemes, are being considered for use at mmWave frequencies. This paper presents preliminary studies on the achievable spectral efficiency on a wireless MIMO link operating at mmWave in a typical 5G scenario. Two different single-carrier modem schemes are considered, i.e. a traditional modulation scheme with linear equalization at the receiver, and a single-carrier modulation with cyclic prefix, frequency-domain equalization and FFT-based processing at the receiver. Our results show that the former achieves a larger spectral efficiency than the latter. Results also confirm that the spectral efficiency increases with the dimension of the antenna array, as well as that performance gets severely degraded when the link length exceeds 100 meters and the transmit power falls below 0dBW. Nonetheless, mmWave appear to be very suited for providing very large data-rates over short distances.Comment: 8 pages, 8 figures, to appear in Proc. 20th International ITG Workshop on Smart Antennas (WSA2016

Single-Carrier Modulation versus OFDM for Millimeter-Wave Wireless MIMO

This paper presents results on the achievable spectral efficiency and on the energy efficiency for a wireless multiple-input-multiple-output (MIMO) link operating at millimeter wave frequencies (mmWave) in a typical 5G scenario. Two different single-carrier modem schemes are considered, i.e., a traditional modulation scheme with linear equalization at the receiver, and a single-carrier modulation with cyclic prefix, frequency-domain equalization and FFT-based processing at the receiver; these two schemes are compared with a conventional MIMO-OFDM transceiver structure. Our analysis jointly takes into account the peculiar characteristics of MIMO channels at mmWave frequencies, the use of hybrid (analog-digital) pre-coding and post-coding beamformers, the finite cardinality of the modulation structure, and the non-linear behavior of the transmitter power amplifiers. Our results show that the best performance is achieved by single-carrier modulation with time-domain equalization, which exhibits the smallest loss due to the non-linear distortion, and whose performance can be further improved by using advanced equalization schemes. Results also confirm that performance gets severely degraded when the link length exceeds 90-100 meters and the transmit power falls below 0 dBW.Comment: accepted for publication on IEEE Transactions on Communication

On the use of multiple satellites to improve the spectral efficiency of broadcast transmissions

We consider the use of multiple co-located satellites to improve the spectral efficiency of broadcast transmissions. In particular, we assume that two satellites transmit on overlapping geographical coverage areas, with overlapping frequencies. We first describe the theoretical framework based on network information theory and, in particular, on the theory for multiple access channels. The application to different scenarios will be then considered, including the bandlimited additive white Gaussian noise channel with average power constraint and different models for the nonlinear satellite channel. The comparison with the adoption of frequency division multiplexing (FDM) is also provided. The main conclusion is that a strategy based on overlapped signals is convenient with respect to FDM, although it requires the adoption of a multiuser detection strategy at the receiver

A highly efficient receiver for satellite-based Automatic Identification System signal detection

An innovative receiver architecture for the satellitebased Automatic Identification System (AIS) has been recently proposed. In this paper, we describe a few modifications that can be introduced on the algorithms for synchronization and detection, that provide an impressive performance improvement with respect to the previous system. The receiver architecture has been designed for an on-board implementation, and for this reason all algorithms have been realized keeping the complexity as low as possible. A prototype for the proposed receiver has been implemented by the University of Parma and CGS S.p.A. Compagnia Generale per 10 Spazio under the ESA project FENICE

Advanced techniques for spectrally efficient DVB-S2X systems

We investigate different techniques to improve the spectral efficiency of systems based on the DVB-S2 standard, when the transmitted signal bandwidth cannot be increased because it has already been optimized to the maximum value allowed by transponder filters. We will investigate and compare several techniques to involve different sections of the transceiver scheme. The techniques that will be considered include the use of advanced detection algorithms, the adoption of time packing, and the optimization of the constellation and shaping pulses. The LDPC codes recently proposed for the evolution of the DVB-S2 standard will be considered, as well as the adoption of iterative detection and decoding. Information theoretical analysis will be followed by the study of practical modulation and coding schemes

THE COMPLEX OF SANTA CROCE IN RAVENNA AS A CASE STUDY: INTEGRATION OF 3D TECHNIQUES FOR SURVEYING AND MONITORING OF A HISTORICAL SITE

Over the last decades, climate change has brought more and more challenges to managers of cultural heritage and researchers. The increasing effects of natural hazards on assets have required the development of a new protocol of techniques and methodologies for the monitoring of Cultural Heritage and the adoption of management plans adapted to the new challenges at every stage of risk management. The work here presented aims at providing an insight of the work undertaken under the framework of the H2020 SHELTER project, to showcase the first steps of the multi-disciplinary research conducted in one of the project’s case studies, the complex of Santa Croce in Ravenna, Italy. The paper provides the presentation of the case study and the description of the surveying activities with some first results, to provide a preliminary assessment of the site criticalities to be addressed in the future activities in the area, in line with the EU project expected outcomes

Thyroid autoimmunity, thyroglobulin autoantibodies and thyroid cancer prognosis

Relevance of thyroid autoimmunity to prognosis of papillary thyroid carcinoma is still unsettled. We decided to investigate the impact of thyroid autoimmunity on prognosis of papillary thyroid carcinoma and the handling of TgAbs. We evaluated the clinical course of a large group of patients according to the presence (PTC-LT) or absence (PTC) of lymphocytic thyroiditis at histology. We studied 194 consecutive patients with a diagnosis of PTC and treated with total thyroidectomy plus ¹³¹I ablation between 2007 and 2009. Median follow-up (with 25th-75th percentiles) was 84·0 (56·4-118·0) months. The remission criteria were: basal Tg <0·2 ng/mL (or stimulated Tg <1), TgAbs <8 IU/mL (otherwise "decreasing TgAb trend", a decline of ≥20% in sequential TgAb measurements) and unremarkable imaging. PTC-LT and PTC patients had comparable treatment.TgAbs were detectable in 72·5% of PTC-LT and 16·5% of PTC patients. Time to remission was longer in the detectable than in the undetectable TgAb cohort (28·5 vs· 7·5 months [median]; HR 0·54, CI 0·35-0·83, p=0·005). When comparing PTC-LT to PTC patients the difference was maintained in the detectable TgAb (29·3 vs 13·0 months; HR 0·38, CI 0·18-0·80; p=0·01), but not in the undetectable TgAb cohort (7·7 vs 7·3 months; HR 0·90, CI 0·55-1·47; p=0·68). Using the decreasing TgAb trend, the influence of detectable TgAbs on time to remission was abolished. Thyroid autoimmunity does not influence the prognosis of papillary thyroid carcinoma. A decreasing TgAb trend seems an appropriate criterion to establish the remission of papillary thyroid carcinoma

Are sinonasal dissection courses a valid instrument for endoscopic sinus surgeons? A report on 7-years of experience

I corsi di chirurgia endoscopica naso-sinusale sono rivolti sia a giovani specialisti per il training chirurgico, sia a chirurghi più esperti per migliorare le abilità chirurgiche. Ad un totale di centotrenta (130) partecipanti, ad 8 corsi di dissezione in totale, tra il 2013 e il 2019, è stato somministrato un questionario strutturato standardizzato, comprendente domande sulla strumentazione ricevuta e problemi riscontrati durante la pratica di dissezione. L’uncinectomia e l’etmoidectomia anteriore sono state considerate le procedure più semplici del corso, dalla maggior parte dei partecipanti, mentre l’approccio al seno frontale, indipendentemente dall’esperienza e dall’età, è stato ritenuto il passaggio più complicato. Tutti i partecipanti hanno considerato il corso di dissezione come un mezzo utile per migliorare le loro conoscenze anatomiche, ed il grado di confidenza con la strumentazione e con la dissezione. I corsi di chirurgia endoscopica naso-sinusale sono stati ritenuti utili sia dai giovani specialisti, che dai chirurghi più esperti. Il miglioramento delle conoscenze anatomiche può ridurre efficacemente l’insorgenza di complicazioni indesiderate, in particolare per gli approcci endoscopici.Sinonasal dissection courses have been reported to be effective in teaching sinonasal anatomy to trainees, and in improving surgical skills for trained surgeons. Between 2013 and 2019, a standardised structured questionnaire was handed out to 130 participants of 8 sinonasal dissection courses. Each questionnaire included questions about the medical equipment the surgeons were fitted, and the problems encountered during the dissection.The majority of the participants, regardless of their experience and age, considered uncinectomy and anterior ethmoidectomy as the simplest parts of the dissection, whereas the most complicated step was the approach to the frontal sinus. All participants considered the dissection course as a useful way to improve their medical skills while performing an endoscopic surgery procedure, such as their anatomical knowledge, and confidence with instrumentation and the dissection. Sinonasal dissection courses can be considered to be useful for both trainees and trained surgeons. Improving anatomical knowledge can reduce the occurrence of complications, especially in endoscopic surgery