China Mobile plots 400 Gigabit trials in 2017

China Mobile is preparing to trial 400-gigabit transmission in the backbone of its optical network in 2017. The planned trials were detailed during a keynote talk given by Jiajin Gao, deputy general manager at China Mobile Technology, at the OIDA Executive Forum, an OSA event hosted at OFC, held in Los Angeles last week.

The world's largest operator will trial two 400-gigabit variants: polarisation-multiplexed, quadrature phase-shift keying (PM-QPSK) and 16-ary quadrature amplitude modulation (PM-16QAM).    

The 400-gigabit 16-QAM will achieve a total transmission capacity of 22 terabits and a reach of 1,500km using ultra-low-loss fibre and Raman amplification, while with Nyquist PM-QPSK, the capacity will be 13.6 terabits and a 2000km reach. China Mobile started to deploy 100 gigabits in its backbone in 2013. It expects to deploy 400 gigabits in its metro and provisional networks from 2018.

Gao also detailed the growth in the different parts of China Mobile's network. Packet transport networking ports grew by 200,000 in 2016 to 1.2 million. The operator also grew its fixed broadband market share, adding over 20 million GPON subscribers to reach 80 million in 2016 while its optical line terminals (OLTs) grew from 89,000 in 2015 to 113,000 in 2016. Indeed, China Mobile has now overtaken China Unicom as China's second largest fixed broadband provider. Meanwhile, the fibre in its metro networks grew from 1.26 million kilometres in 2015 to 1.41 million in 2016.

The Chinese operator is also planning to adopt a hybrid OTN-reconfigurable optical add-drop multiplexer (OTN-ROADM) architecture which it trialled in the second half of 2016, linking several cities. The operator currently uses electrical cross-connect switches which were first deployed in 2011.

The ROADM is a colourless, directionless and contentionless design that also supports a flexible grid, and the operator is interested in using the hybrid OTN-ROADM in its provisional backbone and metro networks. Using the OTN-ROADM architecture is expected to deliver a power savings of between 13% and 50%, says Gao.

XG-PON was also first deployed in 2016. China Mobile says 95% of its GPON optical network units deployed connect single families. The operator detailed an advanced home gateway that it has designed which six vendors are now developing. The home gateway features application programming interfaces to enable applications to be run on the platform.

For the XG-PON OLTs, China Mobile is using four vendors - Fiberhome, Huawei, ZTE and Nokia Shanghai Bell. The OLTs support 8 ports per card with three of the designs using an ASIC and one an FPGA. "Our conclusion is that 10-gigabit PON is mature for commercialisation," says Gao. 

Gao also talked about China Mobile's NovoNet 2020, the vision for its network which was first outlined in a White Paper in 2015. NovaNet will be based on such cloud technologies as software-defined networking (SDN) and network function virtualisation (NFV) and is a hierarchical arrangement of Telecom Integrated Clouds (TICs) that span the core through to access. He outlined how for private cloud services, a data centre will have 3,000 servers typically while for public cloud 4,000 servers per node will be used. 

China Mobile has said the first applications on NovoNet will be for residential services, with LTE, 5G enhanced packet core and multi-access edge computing also added to the TICs.

The operator said that it will trial SDN and NFV in its network this year and also mentioned how it had developed its own main SDN controller that oversees the network.

China Mobile reported 854 million mobile subscribers at the end of February, of which 559 million are LTE users, while its wireline broadband users now exceed 83 million.