Low-Latency Polling for Passive Optical Networks

In this letter, we present a passive optical network (PON) polling mechanism for services that require low-latency performance, which achieves delay performance gains reaching 57%. This is accomplished by decoupling the in-band report messages from the upstream data transmission time window and scheduling them separately in order to arrive immediately before a grant is to be transmitted from the optical line terminal (OLT). We analyze the details of this mechanism and provide discrete event simulation results to support the analysis. We emphasize that the proposed mechanisms maintain a statistical multiplexing approach (as opposed to a fixed window TDM approach), require only firmware upgrades at the OLT, can be rolled out on a per-ONU basis and come only at the cost of one extra guard time per ONU being polled in this manner.