The POSEIDON project aims to define solutions for scalable CF-mMIMO operating in the sub-6GHz frequency bands (where the available spectral resources are scarce) toovercome various chanllenges (coverage, capacity, environmental sustainability…) . In particular, scalable CF-mMIMO architectures must be able to handle i) the dramatic increase in wireless traffic demand, which is caused by the exponential growth of connected wireless devices, and ii) the emerging services/applications requiring huge data traffic (e.g., high-quality video calls, holographic communications and Internet of Things/mMTC). Moreover, as an additional target, POSEIDON will propose architectures that may contribute in the roadmap for the necessary transition to greener solutions and infrastructures. With the ICT sector’s power consumption increasing exponentially through the different generations of radio mobile networks, a tenfold increase of the power consumption for the wireless access is expected over the next decade. Thus, power consumption is among the critical key performance indicators (KPIs) to be optimized in 6G networks. To this end, POSEIDON will provide solutions to satisfy the expected 6G’s requirements with ever-increasingly ubiquitous and reliable wireless connectivity while at the same time steadily addressing the crucial reduction of the ecological impact of cellular infrastructures. The project will focus on lower layers, physical and access, of CF-mMIMO where the consequences of these aforementioned objectives are direct and challenging. This document presents a description of some applicative scenarios and use cases for CF-mMIMO systems which are envisaged in bands below 7GHz: dense mobile broadband network; multi service private network; Vehicular to Infrastructure network; and wide area MTC network. Two setups are proposed for the two first scenarios where studies can be realized on either a theoretical setup (properly configured to well capture the real environment characteristics) or a digital twin model (for better predictions accuracy). An insight on the spectrum availability to deploy such wireless communications is provided. Key performance indicators are also given to evaluate and compare the different achieved technical performances and solutions. A preliminary list of KPIs per scenario with system parameters and performance requirements is also provided in this technical deliverable. A common PHY framework is given for performance assessments. It is worth mentioning that depicted KPIs values constitute a preliminary and an early shaping of targeted parameters for future CF-mMIMO wireless communications, which still need to be validated and confirmed.