China Mobile to Launch 400G Live Network Testing in H2 2014

Morning news on May 22 (Li Ming) — The continuous emergence of emerging services and technologies such as cloud computing, IoT, streaming media, and LTE has placed higher demands on broadband transmission. Just as 100G enters its golden development period, beyond-100G technologies are already on the horizon and gradually maturing.

As 100G gains traction worldwide, the industry's focus has begun shifting toward beyond-100G technologies such as 400G. In this context, at the "2014 China Optical Network Workshop," Li Han, Deputy Researcher at China Mobile Research Institute, stated that China Mobile has completed 400G laboratory testing in the first half of 2014, including mixed laboratory tests involving 4 equipment vendors and 4 types of optical fiber. China Mobile will launch 400G live network trials in the second half of 2014.

400G on the Horizon

It can be said that the rapid development of mobile Internet and the large-scale deployment of LTE have driven China Mobile's rapid adoption of 100G. By 2014, China Mobile's inter-provincial backbone bandwidth will reach 80T, and is expected to reach 260T by 2017, with an average annual growth rate of nearly 50%. Based on these demands, China Mobile has proposed the strategy of "leapfrogging 40G and directly introducing 100G."

"Within 2-3 years, China Mobile will primarily rely on 100G, and will gradually introduce ASON on top of 100G," Li Han noted. "Currently, China Mobile is building the world's largest 100G transmission network, and 100G has demonstrated excellent performance in terms of deployment time, cost, and power consumption."

As 100G just enters large-scale commercial deployment, what drives operators to plan for 400G? Data shows that global IP traffic (fixed and mobile) will reach 1.4ZB (1ZB equals 1,000,000,000TB) in 2017, exceeding the total of all previous "Internet years." Clearly, the surge in network traffic and the sustained substantial growth in transmission rate demands have accelerated the progression of 400G from laboratory to live network testing and even commercial deployment.

According to industry insiders, based on current traffic growth trends, network traffic will grow by nearly 40% annually over the next 5 years, with the transport network dominated by 100G. However, by 2017, the maximum cross-section transmission bandwidth of the backbone network will be approximately 38Tb/s, requiring five 80-wavelength 100G systems. Where feasible, 400G is the more reasonable choice. Over the next 5-10 years, network traffic will grow by approximately 30% annually, and high-traffic regions will require 45-125Tb/s. Where feasible, 400G should be the dominant rate.

China Mobile Completes 400G Laboratory Testing and Launches Live Network Trials in H2

For China Mobile, the rapid development of the mobile Internet in recent years has raised 100G and beyond-100G transmission requirements across all network layers: on the backbone, transmission performance needs further enhancement; in the metro area, there is a need for low-cost, highly integrated 100G and beyond-100G technologies. In addition, LTE deployment will also drive the rapid development of China Mobile's 100G and beyond-100G technologies.

Compared with the 8T transmission capacity provided by 100G WDM systems, 400G can provide 16T to 20T of transmission capacity. Its expected application scenarios mainly include backbone networks, line-side and client-side requirements of large local networks, and data center interconnection requirements. Moreover, if 400G technology is used to complement 100G, it can significantly reduce operators' network construction costs. Therefore, looking ahead, as long as transmission distance and pricing are appropriate, 400G rates will be the more reasonable choice.

Currently, major transmission equipment vendors are already able to provide 400G transmission equipment and 400G solutions. For example, Huawei, Alcatel-Lucent, and Ciena have all released modules based on 400G technology, and 400G standardization efforts are also progressing within various standards organizations.

According to Li Han, "China Mobile has completed 400G laboratory testing in the first half of 2014, including mixed laboratory tests involving 4 equipment vendors and 4 types of optical fiber. China Mobile will launch 400G live network trials in the second half of 2014."

Discussing the choice of 400G transmission technology, Li Han believes that "dual-carrier PM-16QAM is the mainstream technology, with spectral width compressed from 50GHz to 37.5GHz, improving spectral efficiency by 2.6 times. Compared with 100G PM-QPSK, the OSNR tolerance theoretically needs to increase by 6.7dB. In addition, Nyquist WDM can serve as a supplement."

Furthermore, in the post-100G era, SDN is expected to serve 400G, enabling flexible grids, tunable optical module rates/modulation formats, and dynamically configurable physical layers. Li Han stated that SDN will facilitate 400G deployment. Mesh networks require transmission capability of over 2,000 kilometers, cross-connect capacity needs to reach hundreds of T, and 400G has the potential to transmit 2,000 kilometers over conventional fiber. Raman amplifiers should become a mandatory choice for long-distance transmission. Meanwhile, ULL ultra-low-loss fiber can reduce loss by approximately 2dB, and large-effective-area ultra-low-loss fiber can reduce loss by approximately 3dB. SDN will help enable hybrid optical-electrical scheduling.