Motivated by scenario requirements for 5G cellular networks, we study one of the candidate protocols for massive random access: the family of random access methods known as Coded Slotted ALOHA (CSA). A recent trend in research has explored aspects of such methods in various contexts, but one aspect has not been fully taken into account: the impact of path loss, which is a major design constraint in long-range wireless networks. In this article, we explore the behavior of CSA, by focusing on the path loss component correlated to the distance to the base station. Path loss provides opportunities for capture, improving the performance of CSA. We revise methods for estimating CSA behavior, provide bounds of performance, and then, focusing on the achievable throughput, we extensively explore the key parameters, and their associated gain (experimentally). Our results shed light on the behavior of the optimal distribution of repetitions in actual wireless networks.

Next-generation mobile technologies are the enablers for meeting the variable specific requirements of the public safety (PS) community. In particular, due to the development of commercially deployed 5G networks, PS providers look for ways to implement related solutions upon such infrastructures, potentially in a shared use with existing commercial networks. In particular, LTE and 5G NR networks are rapidly gaining recognition as an all-inclusive critical communications platform for the delivery of both mission and business critical applications. Within this scope, we take into account the innovative architectural approach that has been proposed by the 5G ESSENCE project, addressing the paradigms of edge computing and small cell as-a-service that has been realised via a cloud-enabled small cell infrastructure leveraging multi-access technologies in 5G, where we propose a dedicated PS use case, able to offer a mission critical push-to-talk service as well as a Chat and Localisation service. Each one of these services is associated to a dedicated network slice within the scope of the corresponding fundamental 5G ESSENCE architecture and both services are provided via suitable VNFs, thus offering great flexibility to serve PS needs together. We further discuss the overall scenario deployment with the related technical enablers and the proposed functionalities, per case. The corresponding end-to-end slicing makes possible to allocate both radio and cloud resources to the involved critical actors, in an automated and elastic way.

Abstract-Interference Alignment is a new solution to overcome the problem of interference in multiuser wireless communication systems. Recently, the Compute-and-Forward (CF) transform has been proposed to approximate the capacity of Kuser Gaussian Symmetric Interference Channel and practically perform Interference Alignment in wireless networks. However, this technique shows a random behavior in the achievable sumrate, especially at high SNR. In this work, the origin of this random behavior is analyzed and a novel precoding technique based on the Golden Ratio is proposed to scale down the fadings experiences by the achievable sum-rate at high SNR.