Michelangelo Ricciulli’s research while affiliated with Huawei Technologies and other places

Iterative demodulation and decoding has been introduced in 2005 by Colavolpe, Barbieri, and Caire to cope with channels affected by phase noise. However, iterations between the channel decoder and the demodulator increase system’s complexity. In this letter, we propose an iterative carrier recovery scheme where the current iteration is based on the hard decisions taken after the previous iteration. The resulting algorithm is easy-to-implement and offers excellent phase noise tracking performance, as demonstrated by the numerical results presented in the letter that are obtained with phase noise generated by linewidths of practical interest and a highly spectral efficient modulation scheme as 256-QAM.

In this paper, the detection of LoRa signals from a low-earth orbit (LEO) satellite is considered. The use of a LEO satellite to collect messages from the terminals, as an alternative to terrestrial base stations in rural areas, represents a major challenge due to the specific impairments of this scenario, e.g., Doppler effects and interfering signals. A redesign, whose validation is assessed through a system simulator operating in a realistic scenario, is thus required.

We investigate the problem of increasing the spectral efficiency of current high rate telemetry systems in two different scenarios, which exploit one and two channels, respectively. We will analyze several techniques aimed at improving different stages of the transceiver scheme. We will optimize the transmission parameters and apply advanced receiver architectures, able to take into account part of the channel memory and of the interchannel interference. We will propose a new signal predistortion algorithm, which has very good performance in both considered scenarios, and we will show that, by combining the presented techniques, significant gains are possible over the current configuration. The whole analysis is aimed at providing information theoretical bounds to the achievable transmission rates.

The second-generation specification of the digital video broadcasting for satellite (DVB-S2) was developed in 2003 with the aim of improving the existent broadcasting standard DVB-S. The main new features introduced by DVB-S2 included increased baud rates, higher cardinality constellations (up to 32 points), and more efficient binary codes. The extension to DVB-S2, approved in 2014 with the name DVB-S2X, together with continuous technological evolution, moves further steps in this direction, with the use of constellations with cardinality up to 256 points, improved granularity of modulation and coding schemes, and the possibility to increase the baud rate. In this scenario, it is important to be able to ascertain what is the best transceiver structure, starting from the choice of the shaping pulse and the baud rate of the transmitted signals and ending with the most promising receiver architectures, with the aim of maximizing the spectral efficiency. In this paper, we will discuss some of the aspects of this investigation, namely, the optimization of transmission parameters and the description of an efficient receiver. We will then assess the performance of the proposed scheme in comparison with a classical DVB-S2 architecture. Some synchronization aspects will also be discussed, to account for the impairments introduced by the channel. Copyright © 2015 John Wiley & Sons, Ltd.