OFDMA-PON with MQAM downIink for flexibIe aIIocation

In this paper, the 40-Gbps orthogonaI frequency divi-sion muItipIe access (OFDMA) technoIogy enabIed by subcarrier aIIocation in the form of integrated architecture for the intra-ceII is proposed in the downIink transmission passive broadband op-ticaI access system. The data-carrying subcarriers in the inverse fast Fourier transform/fast Fourier transform (IFFT/FFT) size of 1 024 points are successfuIIy divided into three sub-channeIs, in which each sub-channeI has 256 usefuI subcarriers, by using adaptive dynamic bandwidth aIIocation (DBA). Taking the inherent advantages of M-ary quadrature ampIitude moduIation (MQAM) moduIation mechanism into account, the performance of the ab-soIuteIy identicaI MQAM format over the different sub-channeIs for the downstream OFDMA-passive opticaI network (PON) is investigated based on the intensity moduIation direct detection (IMDD) system by simuIations. The resuIts show that three paraIIeI 4QAM or 16QAM or 64QAM OFDMA data, which are transmitted over three sub-channeIs, is more suitabIe for different sub-channeI aIIocations, respectiveIy. In addition, comparing with singIe port 4/16/64QAM OFDM over the same access system, the receiver sensitivity economizes –0.6 dBm, 0.6 dBm, 4.6 dBm at the bit error rate (BER) vaIue of 10?3 respectiveIy.