| dc.description.abstract | An experience common to smartphone users is the
difficulty in accessing services in crowded scenarios, such as a rock concert or a football match. In these cases, to (partially) mitigate frustration, users generically claim that network congestion is occurring, and try again and again to access the network with their smartphones: the result is that user frustration and network congestion reinforce each other! This paper investigates the root
causes of poor performance of cellular networks in crowded
environments, and shows that the commonly adopted random
access procedure can prevent full utilization of wireless resources. We develop a simple, yet accurate analytical model, to analyze why attempting random access to wireless resources can become a problem even when access congestion avoidance is enforced, e.g., with the Access Class Barring (ACB) technique. The model we propose suggests that cluster-based network access, leveraging device-to-device communications, significantly alleviates access problems. Moreover, it sheds light on scalability laws that govern
network utilization and quality of experience, in terms of cell capacity, number of access channels, and cluster size. | |
