Comparison of OFDMA and GFDMA for Next-Generation PONs

This paper examines and compares the use of orthogonal frequency division multiple access (OFDMA) and generalized frequency division multiple access (GFDMA) multicarrier formats in next-generation passive optical networks (PONs) through experimentation and numerical simulations. It is demonstrated that GFDMA presents a high resilience toward multiple access interference (MAI) compared to OFDMA at the uplink channel of a PON. Moreover, two methods are proposed for achieving synchronization in the uplink channel of PONs, enabling high spectral efficiency. These proposed methods can lead to the elimination of inter-ONU guard bands, and facilitate overlapping inter-ONU subcarriers, while eliminating the effects of MAI. Additionally, the performance of these multicarrier formats was analyzed in the downlink channel at a data rate of 15.6 Gb/s and a transmission span of 50 km where neglible performance penalty was observed.