Overview of 50G PON
Updated at Dec 17th 20241 min read
From 10G to 50G: The Evolution of PON Technology
Standard organizations such as FSAN, ITU-T, and IEEE have played a crucial role in advancing PON technology. Today, GPON and EPON are widely used in commercial deployments. Meanwhile, 10G PON equipment has matured and is now at a pivotal stage for large-scale commercial rollout.
But 10G isn't the end for PON technology. The industry widely believes that PON needs to evolve to higher speeds, driving the development of 50G PON.
PON Technology | Downlink Speed | IEEE | ITU-T |
GPON/EPON | 2.5G/1.25Gbps | EPON (IEEE 802.3ah) | GPON (ITU-T G.984) |
10G PON | 10Gbps | 10G-EPON (IEEE 802.3av) | XG-PON(ITU-T G.987) XGS-PON(ITU-T G.9807) |
50G-PON | 25G/50Gbps | 25G/50G-EPON (IEEE 802.3ca) | 50G-PON (ITU-T G.9804) |
New-Generation PON Technology: 50G PON
After 10G PON, next-generation PON technology evolves along two paths. One focuses on increasing single-wavelength transmission rates, and the other uses multiple wavelength overlays. IEEE and ITU-T are actively advancing research in these areas.
IEEE led the way by launching the standardization of next-generation PON technology with the NG-EPON standard, known as IEEE 802.3ca. This standard supports downstream speeds of 25G and upstream speeds of 10/25G on a single fiber while maintaining compatibility with 10G EPON. It uses multi-wavelength overlays and channel bonding to achieve transmission speeds of up to 50Gbps.
Following the completion of the XG(S)-PON standard, FSAN initiated the development of NG-PON2, which succeeded the 10G PON standards (10G GPON and 10G EPON). In April 2012, FSAN decided to adopt TWDM-PON technology for NG-PON2. ITU-T later established this approach as the G.989.x series standard, finalized in 2015. However, high costs of tunable optical devices and system maturity issues have slowed NG-PON2's commercial deployment, leading to decreased industry enthusiasm for its overlay architecture.
In February 2018, driven by a proposal from Chinese industry groups, ITU-T SG15 Q2 began work on the single-channel 50G TDM PON series standard, named "G.HSP (G.Higher Speed PON)," targeting commercial availability by 2025. The 50G PON standard consists of four parts:
G.9804.1 (General Requirements): Covers system requirements, evolution, coexistence, supported services, and interfaces.
G.hsp.COmTC (Common Transmission Convergence Layer): Includes TC layer architecture, physical and service adaptation layers, and management processes.
G.hsp.50Gpmd (Physical Media Dependent Layer): Specifies the physical layer for 50 Gbps TDM PON, including architecture and optical interface parameters.
G.hsp.TWDMpmd (TWDM Physical Media Dependent Layer): Details the physical layer for 50 Gbps TWDM PON, including architecture and optical interface parameters.
Between 2021 and 2023, the 50G PON standard underwent research and revision. In 2023, the ITU-T SG15 plenary session approved G.9804.3 Amd.2, marking the completion of the 50G PON international standard system.
Why Is 50G PON Needed
Due to the collaborative efforts of standard organizations and industry, 50G PON now delivers a transmission rate of 50Gbps. But why is there a need for 50G PON, and where can it be applied?
The rise of video services as a major traffic source, coupled with PON's expansion into campus networks, telemedicine, and smart manufacturing, has significantly increased bandwidth demands. There's also a growing need for lower latency, reduced packet loss, and better service quality. For example, VR applications require over 1 Gbit/s in bandwidth and latency under 5 milliseconds (round-trip) for optimal performance. Telemedicine requires end-to-end latency below 50 milliseconds and jitter under 200 microseconds. Additionally, Wi-Fi 7 access points can deliver peak throughput rates exceeding 40 Gbps. This has driven growing interest and adoption among vendors and operators to transition to 50G PON.
50G PON offers five times more bandwidth than 10Gbps PON technology and showcases lower latency, reduced jitter, and higher reliability. This makes it possible to improve service quality and support new applications. With the same bandwidth convergence and split ratio, it supports a shift from gigabit to 10-gigabit access, meeting the demands of the 10-gigabit era in areas such as digital home life, industrial digital transformation, and urban digital infrastructure.
The Coexistence of PON Technology
Currently, mainstream deployed technologies such as EPON, GPON, 10G EPON, and XG(S)-PON operate on different wavelengths. Leveraging this difference, GPON and XG(S)-PON can coexist through Combo PON or XPON-WDM equipment.
However, limited wavelength resources in access networks leave little room for 50G-PON. The ITU-T has clearly stipulated, after extensive discussions, that 50G-PON cannot coexist with GPON and 10G PON simultaneously. This poses a key challenge for 50G-PON: how to achieve smooth evolution while leveraging existing PON equipment and ODN networks.
To address this challenge, a two-step migration strategy can be adopted: first upgrading from GPON to XG(S)-PON, and then migrating to 50G-PON. Based on WDM principles, XG(S)-PON and 50G-PON can coexist through two approaches:
Independent XPON-WDM Devices: Utilize separate WDM equipment to enable signal coexistence.
50G PON Combo PON: Integrate both technologies within a single device for seamless coexistence.
50G-PON: The Future of Broadband Technology
50G PON is undoubtedly a key technology for future fiber access networks, and here are the reasons why:
ITU-T Standardization: 50G-PON supports industry standards, which is a critical factor for successful commercialization.
PON Coexistence: 50G-PON seamlessly coexists with 10G PON on the same optical distribution network (ODN), enabling flexible and cost-effective evolution as the network grows.
Industry Support: Leading global operators and PON product suppliers support the development of 50G-PON and have conducted pilot trials, advancing the maturity of 50G PON.
The prospects for 50G PON are promising, but the technology is still undergoing development and refinement and has not yet been widely commercialized. Consequently, GPON, EPON, and XG(S)-PON remain the mainstream options in the current market. FS offers GPON, EPON, and XG(S)-PON equipment. These solutions have been validated by the market, effectively meet the diverse needs of today, and are ready for future technological upgrades.
Conclusion
The journey of PON technology from GPON and EPON to 50G PON signifies a remarkable progression in fiber access networks. In the future, 50G PON is expected to usher in a new era of faster and more intelligent fiber access with its superior transmission capabilities and flexible network evolution solutions. Over time, 50G PON is bound to become an essential pillar of modern broadband networks, continually driving the progress and widespread of communication technology.