Device-to-device communication in 5G cellular networks: challenges, solutions, and future directions

TLDR

Conventional cellular networks prohibit direct device‑to‑device communication, routing all traffic through base stations, whereas emerging 5G architectures propose a two‑tier system that enables device‑to‑device links and introduces new technical challenges. This article aims to outline the challenges of a two‑tier macrocell–device network and to propose pricing schemes that encourage device participation. The authors describe a two‑tier architecture where devices act as relays in a massive ad hoc mesh, requiring secure privacy‑preserving routing, smart interference management, resource allocation, and incentive‑based pricing to maintain macrocell performance.

Abstract

In a conventional cellular system, devices are not allowed to directly communicate with each other in the licensed cellular bandwidth and all communications take place through the base stations. In this article, we envision a two-tier cellular network that involves a macrocell tier (i.e., BS-to-device communications) and a device tier (i.e., device-to-device communications). Device terminal relaying makes it possible for devices in a network to function as transmission relays for each other and realize a massive ad hoc mesh network. This is obviously a dramatic departure from the conventional cellular architecture and brings unique technical challenges. In such a two-tier cellular system, since the user data is routed through other users' devices, security must be maintained for privacy. To ensure minimal impact on the performance of existing macrocell BSs, the two-tier network needs to be designed with smart interference management strategies and appropriate resource allocation schemes. Furthermore, novel pricing models should be designed to tempt devices to participate in this type of communication. Our article provides an overview of these major challenges in two-tier networks and proposes some pricing schemes for different types of device relaying.