Multi-Radio Heterogeneous Networks: Architectures and Performance

It is well-known that next generation (5G) wireless networks will need to provide orders of magnitude more capacity to address the predicted growth in mobile traffic demand, as well as support reliable connectivity for billions of diverse devices, which comprise the " Internet of Things." While the industry is focused on a concerted effort to improve capacity of cellular networks, operators are increasingly using WiFi technology over un-licensed spectrum to relieve congestion in their networks. This paper argues that the trend towards integrated use of multiple radio access technologies (RATs) and networks, such as WiFi, will be essential for addressing the challenges faced by future 5G networks. In particular we expect that joint use of multiple RATs can yield beyond additive gains in user connectivity experience by exploiting the rich multi-dimensional diversity (e.g., spatial, temporal, frequency, load, etc.) available across multiple radio networks. We investigate such benefits through a case study on integrating WiFi with 3GPP heterogeneous networks. Our results show that intelligent integration of WiFi/3GPP radio networks can yield an additional 2-3x gains in system capacity and user quality of service, beyond what is achievable from independent use of both networks.