Modeling Multi‐Radio Coordination and Integration in Converged Heterogeneous Networks

In recent years, analysts have been predicting strong and continuous increases in mobile traffic, causing industry and academia to seek methods to improve wireless network capacity. As a result, heterogeneous multi‐radio networks have emerged as novel network architectures. These consist of hierarchical deployments of increasingly smaller cells. Another recent method of providing significant wireless capacity gains is creating “ad hoc” small cells based on direct connections between proximate user devices.In the envisioned fifth‐generation (5G) heterogeneous deployments, each user device will employ multiple radio access technologies for communicating with the network infrastructure or other proximate devices. With the growing numbers of such multi‐radio consumer devices, network operators are increasingly willing to leverage spectrum across diverse radio technologies to boost capacity and enhance quality of service. In this chapter, we review major challenges in delivering uniform connectivity and service experience to converged multi‐radio heterogeneous deployments, including device‐to‐device communications capability, and with a particular emphasis on comprehensive multi‐radio integration and link selection.We propose that devices be continually associated with the cellular infrastructure and use this connectivity to help manage their unlicensed‐band connections. To this end, we anticipate that multiple radios and the associated device/infrastructure intelligence for their efficient use will become a fundamental characteristic of future 5G technologies. Distributed unlicensed‐band networks, such as WiFi, may take advantage of the centralized control function residing in cellular networks such as 3GPP LTE. In particular, we demonstrate that assisted offloading of cellular user sessions onto the unlicensed spectrum improves the degree of spatial reuse and reduces the impact of interference.