Backhauling/Fronthauling for Future Wireless Systems

In a mobile communication system, the segment that connects the core to the access networks is termed the ‘backhaul’. The edges of any telecommunication network are connected through backhauling. The importance of backhaul research is spurred by the need for increasing data capacity and coverage to cater for the ever‐growing population of electronic devices – smartphones, tablets and laptops – which is foreseen to hit unprecedented levels by 2020. The backhaul is anticipated to play a critical role in handling large volumes of traffic, its handling capability driven by stringent demands from both mobile broadband and the introduction of heterogeneous networks (HetNets). Backhaul technology has been extensively investigated for legacy mobile systems, but is still a topic that will dominate the research arena for next generation mobile systems; it is clear that without proper backhauling, the benefits introduced by any new radio access network technologies and protocols would be overshadowed.
Traditionally, the backhaul segment connects the RAN (radio access network) to
the rest of the network where the baseband processing takes place at the cell site. However, with the onset of next generation networks, the notion of ‘fronthaul access’ is also gaining momentum. The future technology roadmap points towards SDN (software‐defined networks) and network virtualization as means of effectively sharing resources on demand between different mobile operators, thus taking a step towards reducing the operational and capital expenditure in future networks. Moreover, the baseband processing will be centralized, allowing the operators to completely manage interference through coordinated resource‐management strategies. In fact, 3GPP are today visualizing a C‐RAN (cloud-RAN) architecture, where the evolved base stations are connected to the C‐RAN unit through communication hauls, to what is referred to as the ‘fronthaul network’. Traditionally, fibre‐optic technology is used to roll out the deployment of base stations; however, this comes along with inherent limitations, including cost and lack of availability at many small sites. This provides the impetus for radio solutions that can handle large volumes of traffic on the fronthaul access, triggering the research community at large to find
alternative and advanced solutions that can supersede fibre.
The current work on backhaul and fronthaul technology is fragmented, and still
in its infancy. There are still giant steps to be taken towards developing concrete solutions to provide a modern communication haul for next generation networks, which is also commonly referred to as 5G. This book aims to be the first of its kind to hinge together the related discussions on the fronthaul and backhaul access under the umbrella of 5G networks, which we will often refer to as the ‘communication haul’. We aim to discuss these pivotal building blocks of the communication infrastructure and provide a view of where it all started, where we are now in terms of LTE/LTE‐A networking and the future challenges that lie ahead for 5G. In addition, this book presents a comprehensive analysis of different types of backhaul/fronthaul technologies while introducing innovative protocol architectures.
In the compilation of this book, the editors have drawn on their vast experience in international research and being at the forefront of the communication haul research arena and standardization. This book aims to be the first to talk openly about next generation communication hauls, and will hopefully serve as a useful reference not only for postgraduate students to learn more about this evolving field, but also to stimulate mobile communication researchers towards taking further innovative strides in this field and marking their legacy in the 5G arena.