Light-Trail Design for 5G Backhaul: Architecture, SDN Impact and Coordinated Multipoint

5G promises to be revolutionary from the perspective of offering unprecedented bandwidth to the end user. In this pursuit, the limited spectrum of the wireless overlay, further constricted by distance, requires strong support from a backhaul network. Such a strong backhaul network should provide large bandwidth pipes with near proximity to the end user at low costs and using pragmatic technology. Naturally, an optical solution is best suited to meet the voluminous bandwidth requirements of the backhaul. This optical solution has to cater to dynamic bandwidth needs among base stations and provide rapid and smart provisioning to meet the requirement of new features such as Coordinated Multipoint (CoMP) among base stations, and yet be low cost. To this end, we propose the use of light-trails (LTs), which are a generalization of a lightpath that provides for dynamic bandwidth communication, sub-wavelength optical grooming and optical layer multicasting using contemporary optics. We observe that each feature of a LT, i.e., dynamic provisioning, optical multicast, and sub-wavelength grooming is strongly desired by the 5G backhaul, implying a clear mapping between them. We investigate the usage of light-trails as a 5G backhaul solution. We discuss the proposed architecture of light-trails for micro cells, pico cells, and femto cells. We present the LT design problem for 5G backhaul as a constrained optimization problem. We also present a mechanism to achieve coordinated multipoint using light-trails. A dynamic virtual topology growth algorithm for the backhaul is also presented and extensively evaluated. The light-trails approach is compared to other approaches, the use of an SDN controller is discussed and significant performance benefits are observed.