Modeling of LTE back-hauling through OFDMA-PONs

Abstract

This paper evaluates a novel mapping and scheduling scheme which allows efficient control over the quality-of-service (QoS) experienced by long term evolution (LTE) users when backhauled over an orthogonal frequency division multiple access-passive optical network (OFDMA-PON). With respect to mapping, the LTE QoS class identifiers (QCIs) are assigned to the OFDMA-PON priorities based on class-of-service (CoS) differentiation. Scheduling involves the allocation of subcarriers to each optical network unit/enhanced node B (eNB/ONU) ensuring that the bandwidth allocation accounts for the QoS requirements of the respective LTE wireless bearers. Since the transmission pipes allocated to each eNB/ONU are to be shared by all CoS queues, fairness across traffic priorities throughout the network is achieved by introducing a weighted dynamic subcarrier assignment (WDSA) algorithm. Simulations are based on a 10Gbps OFDMA-PON with 1024 subcarriers, 20km reach and 32 eNB/ONUs. Performance evaluation figures confirm that the end-end wireless packet delay and queue lengths of the high priority queues benefit significantly from the application of the WDSA algorithm without failing the rest of the network performance