Enhancing the survivability and power savings of 5G transport networks based on DWDM rings

So much has been promised by the fifth generation (5G), the revolution of mobile communications that allows for flexible, speedy, and efficient delivery of unlimited data and information sharing between people located anywhere and at any time. The road toward making 5G a reality, however, requires concerted efforts in designing both the underlying infrastructure and the enabling technologies to simultaneously satisfy not only capacity but also reliability, low latency, synchronization, security, and energy consumption requirements. In that respect, the transport segment of a 5G network, i.e., the backhaul network of mobile base stations (BSs) or fronthaul of remote radio units (RRUs), must not be overlooked. Further, any future design of a resilient 5G transport network must also consider the potential exploitation of switching on and off network resources such as RRUs and BSs to improve energy efficiency. At present, there are few inroads on 5G transport networks that provide resilience during sleep mode operation. Therefore, the focus of this work is aimed specifically at providing solutions to enhance both the survivability and power savings of mobile transport networks that implement sleep mode operation. We develop our solutions around a dense wavelength-division multiplexed (DWDM) optical ring transport network that has been previously proven to be energy efficient as a 5G transport network. Further, we propose two survivable schemes that exploit the inherent resiliency of the ring network. In conjunction with cw monitoring signals and highly sensitive monitoring modules, these schemes facilitate for the first time continuous monitoring of the network at all times, even during idle periods of transmission when transceivers are sleeping. That is, our proposed schemes enable network energy savings through sleep mode operation without having to compromise on failure detection time. Compared to a conventional ring architecture, our survivable schemes provide enhanced connection availability and power savings at less than 0.2% incremental network cost. Based on performance evaluations for brownfield, duct reuse, and greenfield deployments, we provide guidance on the most suitable scheme for each considered scenario, thus driving the future choices of mobile network operators.