Transport Mechanisms for Mobility Support in Optical Slot Switching-Based Next-Generation Mobile Backhaul Networks

Abstract

In order to implement the next-generation (e.g., LTE-A) mobile backhaul networking segment, an optical slot switching solution called packet optical add/drop multiplexer (POADM) was previously proposed. Optical slot switching is at the same time a high capacity, energy-efficient, and low-latency optical transport network technology that relies on the direct transmission of data from base station to base station without resorting to time-consuming electronic processing and energy-hungry optoelectronic conversions. Low latency is an important requirement of mobile backhaul networks for real-time traffic such as Coordinated MultiPoint (CoMP) and POADM was shown to be compatible with the strict latency requirement of CoMP—1 ms end-to-end—even for very high network loads of 80% and above. However, user mobility was not taken into account. The traffic of users moving from one cell to another cell during handovers should also meet this strict requirement. In this paper, we propose and evaluate several transport mechanisms to support User Element mobility at the optical layer in a next-generation mobile backhaul network implemented using our previously proposed optical slot switching technology. We show with simulations that with smart introduction of additional electronic processing for handover traffic only (traffic of user elements that have moved from one cell to another), very strict latency constraints (sub-ms) can be met even for the time-sensitive mobile traffic.