We analyse some of the candidates for modulations for 5G: FBMC-OQAM, GFDM-OQAM, and WCP-COQAM. Unlike most of the related bibliographies, which are oriented to mobile communications, our research is focused on 5G in cognitive radio based industrial wireless communications. According to the ultrareliability and low-latency requirements of industrial communications, we simulate the aforementioned modulations in low-band transmissions (carrier frequencies below 6 GHz and a bandwidth narrower than 100 MHz) through large indoor spaces and severe multipath channels that emulate industrial halls. Moreover, we give detailed information about WCP-COQAM and how the windowing affects the protection against multipath effect and reduces spectral efficiency compared to GFDM-OQAM. We also compare the aforementioned filtered multicarrier techniques and OFDM in terms of robustness against multipath channels, power spectral density, and spectral efficiency. Based on these results, we aim at providing an approximate idea about the suitability of 5G MCM candidates for industrial wireless communications based on CR.

The main challenges for current industrial wireless solutions are the stringent real-time requirements of industrial automation applications and the harsh propagation channel conditions in this kind of scenarios. Most of the current industrial wireless communications are based on existing standards like IEEE 802.11, IEEE 802.15.1 or IEEE 802.15.4 and additionally proprietary protocol extensions are applied over them. These communication systems cover a wide range of industrial applications but they lack robustness when it comes to tight real-time requirements for factory automation. Hence, new schemes for the physical layer, along with new media access techniques, for industrial wireless communications must be proposed. Among the upcoming technologies, modulation candidates for 5G and cognitive radio might be promising solutions. In this article we analyse FBMC-OQAM, GFDM-OQAM and WCP-COQAM modulation candidates for 5G in terms of bit error rate, power spectral density and spectral efficiency over highly dispersive channels. From this analysis, on the one hand, we assess the suitability of these modulation systems for industrial wireless communications based on cognitive radio. On the other hand, we provide additional details about how windowing affects the protection against highly dispersive multipath channels and the spectral efficiency in WCP-COQAM.

This paper presents a flexible and scalable battery system for maritime transportation, integrating modular converters and hybrid battery technologies that are effectively implemented in real-world scenarios. The proposed system is realized with modular DC-DC converters, which do not require complex design and control or a high number of components and combine high-power (HP) and high-energy (HE) battery cells to optimize the energy and power requirements of vessel operations without oversizing the energy storage system. Moreover, the modular design ensures flexibility and scalability, allowing for easy adaptation to varying operational demands. In particular, the system topology, control mechanisms, and communication protocols are explained in this paper. The concept has been validated through simulations and real-scale laboratory tests, demonstrating its effectiveness. Key results highlight the system’s ability to maintain the DC bus voltage while operating at high efficiency (ranging from 97% to 98%) under different load conditions, supported by reliable and demanding real-time communication using the EtherCAT standard. This real-time capability has been validated, and related results are presented in this paper, showing a synchronization accuracy below 200 ns between two modules and a stable control at a cycle time of 400 µs. This approach offers a promising solution for reducing greenhouse gas emissions in the maritime industry, aligning with global sustainability goals.