Synchronizing the Packet Optical Network

Optical Fiber Perimeter; Image Courtesy: Fiber SenSys

G-PON is a popular technology for 5G backhaul, mobile fronthaul and for last-mile access.


The massive rollout of LTE base stations to satisfy the ever-increasing demand for traffic has forced operators to consider a variety of transport networks to carry backhaul traffic. Among the wireline options, G-PON as a fiber-based access network is well suited for this function because it can support high bandwidth.

NG-PON2, a more recent standard, supports 40 Gbps throughput using techniques such as Time and Wavelength Division Multiplexing (TWDM) to deliver up to 10 Gbps symmetric bandwidth per subscriber. NG-PON2 also allows co-existence of TWDM and legacy G-PON systems.

  • G-PON systems inherently carry an accurate and stable frequency reference in the physical layer

  • G-PON systems use a specialized mechanism (G.984.3 Amendment 2) to distribute Time-of-Day between the OLT and ONU

  • However, LTE and 5G networks require phase/time and typically have an embedded PTP slave in the eNodeB. G-PON's G.984.3 Amendment 2 must therefore coexist with PTP

  • In this case, phase synchronization between the ONU and OLT may be viewed as a "distributed boundary clock". This is akin to having a PTP slave function in the OLT and a PTP master function in the ONU

Distrubuted Boundary Clock

Qulsar's products are designed to meet G-PON/X-PON requirements.

  • Qg 2 Multi-Sync Getaway can be deployed as a Grandmaster for the backhaul or fronthaul network, or as a boundary clock for a scalable synchronization network.

Copyright © 2023 Qulsar Inc. All rights reserved. Privacy Policy