The evolution of mobile networks towards the Fifth Generation (5G) introduces many concerns from the technical and economic points of view. Expected new applications exceed mobile networks' current capabilities, and 4G networks will have to evolve into 5G networks to provide some with a proper service. With regard to the ambitious intended performance of 5G networks, a huge process is required which will need to be faced up to both technically and economically. The 5G "ready system" standard is scheduled for 2020. However, only a few studies have carried out techno-economic evaluation of 5G. This paper presents a techno-economic analysis to foresee some feasible technical architectures leading to suitable and affordable use cases. The paper presents a new approach based on different evolving technical scenarios, establishing combined 4G/5G technical solutions and a roadmap that could provide useful insights about the most suitable use cases by scenario. Moreover, it analyses these possible use cases to determine their feasibility by optimizing their deployment costs. The study is based on the standardization process, integration of different views of key industrial players and mathematical modelling to address the new applications that 5G will provide. Finally, conclusions are drawn from the analysis and a recommendation score is established, providing useful advice to support the strategic decisions of the different stakeholders, technologists and investors involved in deployment of 5G networks.

The arrival of the fifth generation (5G) of mobile communications is boosting vehicular communications, an important use case addressed in the recent years. LTE introduced a sidelink radio interface through which user equipment would communicate directly with no necessary dependence on the network, named PC5. 5G has defined its own sidelink interface, NR-Sidelink, envisaged to improve PC5. This paper analyses the use of Demodulation Reference Signals (DMRS) to estimate the channel in sidelink communications. Improving several mappings proposed by the standards, the main contribution proposed in this paper is a new DMRS mapping with a better performance. The proposed Unequal Pilot Spacing (UPS) mapping can enhance the standard with a satisfactory trade-off between performance and overhead.