Hierarchical wireless and optical access networking: Convergence and energy efficiency

Node consolidation and an all-passive (PON) infrastructure are important aspects to next-generation optical access (NGOA) networking. Wireless access is another important trend (WiFi, LTE/4G etc.) but requires active outside plant (base-stations). Once electrically-powered (e.g. via renewable energy) outside plant becomes a feature of an integrated NGOA architecture, the question of whether the NGOA network can be adapted and optimised still further (e.g. location of cognitive radio intelligence, vertical handover, locality, caching/content storage etc.) needs to be explored, as well as the additional energy-efficiency savings available with respect to optimising green radio technologies versus low-energy photonics. In this paper, we discuss the issues involved in the optimised design of a hierarchical and converged fixed-wireless access network, focussing on the handover possibilities associated with heterogeneous wireless technologies and the impact on the optimised design of an underlying fixed optical access infrastructure.