Energy-efficient bandwidth and wavelength allocation in HS-PONs with a dedicated activation wavelength

In higher-speed passive optical networks (HS-PONs), an upstream dedicated activation wavelength (DAW) is introduced to eliminate the latency caused by periodically creating quiet windows (i.e., time slots) for optical network unit (ONU) activation, thus supporting emerging time-sensitive services. As for the DAW, only part of the bandwidth is reserved for ONU activation, and the remaining bandwidth can still be used to transmit data frames of non-time-sensitive services. However, the existing dynamic bandwidth allocation mechanism tailored for PONs with a single wavelength cannot support cooperative bandwidth scheduling of working and activation wavelengths. In addition, even though transmitting data frames by the DAW can improve the performance in terms of latency and throughput, it brings high energy consumption, especially for the optical digital signal processing function being performed in ONUs. In this paper, we address the above problems by enhancing the existing scheduling protocols for HS-PONs with DAWs to enable bandwidth scheduling of two wavelengths in a unified way, based on which the maximum upstream latencies are further analyzed. Furthermore, we also propose an energy-efficient bandwidth and wavelength allocation scheme, in which the number of operating wavelengths can be reduced while meeting the services’ latency requirements. Simulation results show that the proposed scheme outperforms the benchmarks in terms of energy saving, without affecting the latency constraint, thus well satisfying services’ diverse requirements.