Application of feasible vertex labeling for dynamic capacity allocation of a multicarrier multimode PON

Multimode PON is considered as a potentially cost-effective solution for a Full Service Access Network. To avoid the limited bandwidth-distance product of multimode fiber when using baseband transmission, passband transmission which utilizes highorder transmission lobes in GHz region of the electrical-domain link frequency responses can be used instead [1]. However, due to the intermodal dispersion, the link frequency responses in general are frequency-selective for broadband serial transmission in the order of 100 Mbps (i.e., when only one subcarrier is used for transmission between the OLT and each ONU). Here, the impact of the chromatic dispersion is considered to be negligible for the distances of up to a few kilometers envisioned for the PON under consideration by using appropriate optical wavelengths. Therefore, we assume the use of multicarrier transmission which can mitigate the aforementioned impairment. Recent researches have considered the use of an optical OFDM scheme (e.g., [2,3]), which is a specific case of multicarrier transmission through an optical fiber, for similar reasons. An important aspect of this kind of system is that different subcarriers generally experience different subchannel normalized signal-tonoise ratios (nSNRs), i.e., the ratio of the subchannel gain to the subchannel noise power. Moreover, these subchannel nSNRs are ONU-dependent and time-dependent. For this system, it is compelling to employ a dynamic capacity allocation which can exploit those time-dependent subchannel nSNRs in order to increase the overall system capacity such that the system can accommodate more traffic load.