Recently, China Telecom launched the 2022 5G fronthaul equipment collection, of which LWDM entered the group level for the first time. Although it is not as large as the traditional and mature CWDM, it also means that after more than a year of live network pilots, China Telecom will commercialize LWDM technology nationwide.
LWDM's transition from the laboratory to the live network is also an important step for China Telecom to take in scientific and technological innovation, especially in the context that technological innovation has become the embodiment of competitiveness in the development process of domestic enterprises in recent years. Of course, As the main force of central enterprises, China Telecom released a scientific and technological innovation action plan at the 2021 Tianyi Intelligent Ecological Expo, practicing scientific and technological innovation with practical actions, and striving to "benefit from the mouth".
Where is LWDM innovative?
Before the commercial launch of 5G in 2019, 5G fronthaul (that is, 5G base station signal transmission to BBU) as a very large part of the 5G network investment, the three major operators attach great importance to it, have launched innovative solutions.
In the C-RAN scenario, it has become a consensus that 5G fronthaul selects xWDM technology as the mainstay, and the fiber resources of base stations will become increasingly scarce, and the subsequent development should try to save the use of optical fiber. At the same time, with the construction and operation of 5G scale, the reliability, maintainability and scalability of the fronthaul system are crucial and need to be considered forward-looking.
China Telecom's solution is to ask for bandwidth in the O-band. Li Junjie, chief expert of China Telecom Optical Transmission, pointed out that the unique advantage of the O-band is that it is in a low dispersion region, with the development of optical networks, the gold mine in the O-band is worth mining, and for 5G fronthaul, the O-band can perfectly match the demand.
Therefore, in the face of the requirements of 5G fronthaul for low cost, transmission performance, transmission distance, reliability, synchronization, link budget, etc., as well as the requirements for the speed and quantity of fronthaul interfaces for 5G co-construction, sharing and sustainable development, combined with the consensus of the industrial chain, China Telecom has led the proposal of LWDM (Fine Wave Division Multiplexing) solution.
The LWDM scheme uses a mixed-rate wavelength division system of 25Gb/s and 10Gb/s. With high bearing efficiency, single fiber supports 6 channels of 25Gb/s front inheritance load, while reserved 6 channels of 10Gb/s front inheritance load capacity; high transmission performance, 25Gb/s wavelength is concentrated in the zero dispersion wavelength area of 1310nm, with obvious low dispersion cost advantage; high reliability, 25Gb/s optical modules are all configured with TEC to ensure performance and life; high maintenance margin, to ensure more than 3dB maintenance margin, to meet the ultra-specification long-distance transmission.
In addition, in the face of C-RAN's increase in optical fiber, pigtail fiber, and the introduction of a combined splitter, the potential fault points of the 5G fronthaul section are increased, and the difficulty of operation and maintenance is increased. The introduction of semi-active solutions can improve the maintenance capabilities of fronthaul transmission, improve service availability, and achieve good results in the pilot of the existing network.
Scientific and technological innovation needs to be pragmatic
Despite all these advantages, in the nearly two years since LWDM entered the spotlight, there have been more lab-validated, on-grid small-scale pilots. This is also a common problem faced by the three major operators' respective fronthaul solutions, from the perspective of the millions of 5G base stations that have been deployed on the current network, the number of sites using innovative wireless fronthaul solutions is "better than nothing".
Of course, there are many reasons behind this, including the degree of participation in the industrial chain, how costly it is compared with the existing solution, and whether it effectively solves the pain points.... Through these reasons, we can see that scientific and technological innovation can not only be a slogan, but should return to the essence of pragmatism. At the same time, scientific and technological innovation cannot rely on single-handedness, and it needs to be jointly promoted by the upstream and downstream of the industrial chain.
Or in terms of LWDM fronthaul innovation solutions, the molding of the whole set of solutions involves a complete industrial chain of main equipment, optical modules, optical chips, devices, test instrument manufacturers, etc., which is indispensable. Taking optical transceivers as an example, in this market of about $1 million per year, there are hundreds of suppliers, and the competitive environment is particularly fierce.
In the face of this market environment, most suppliers will choose to follow the mature solution to survive, and some suppliers will choose to support operators' innovative solutions to seek breakthroughs. From a rational point of view, there may be more opportunities to support all current and future technologies, but the cost of research and development, the cost of time is expensive, and if only one technology is bet, once it fails, it will cause greater losses.
Therefore, for the leading party of a certain scientific and technological innovation, it is necessary to achieve "lip service", not simply pull the head to cooperate with your scientific and technological innovation, but also to let the upstream and downstream of the industrial chain see that after doing this, there are predictable prospects. In this way, they have the motivation to invest in research and development, so that the scale of innovative solutions can be landed, so that innovation is no longer on the top, but takes root.
Industry support, target science and technology leader
All along, China Telecom has played a role in promoting the healthy development of the industrial chain, LWDM can smoothly enter the collection directory at the level of China Telecom Group, the application of G.654.E optical cable in the backbone transmission network, etc., and the test of 5G extended small base stations in preparation for collection and mining... are the best evidence.
With such an industrial chain foundation, China Telecom is releasing a scientific and technological innovation action plan, bravely becoming the source of original technology and the head of the modern industrial chain chain, building China Telecom into a science and technology enterprise with independent control of key core technologies, entering the first camp of national scientific and technological innovation enterprises, and striving to become a scientific and technological leader and a national strategic scientific and technological force.
In order to realize this vision, China Telecom has made it clear that from now until 2035, it will build a science and technology leader in three steps and become a national strategic scientific and technological force. The first step is to reach the end of the "14th Five-Year Plan" period to basically realize the autonomy and controllability of the cloud network, which is also a key step. The second step is to build a technology-based enterprise by 2030, with cloud network operation technology leading global operators, and significantly improving international discourse power and influence. The third step is to achieve the ability of scientific and technological innovation to lead the global operators, central enterprises and similar markets by 2035, and become a leading enterprise in science and technology.
Focusing on the first phase of the goal, China Telecom has united the industrial chain, from wireless to access to edge to core to platform, independently develop and build a new infrastructure for cloud-network integration, and use this to create 5G end-to-end customization capabilities, deepen cloud network capabilities into various industries, better empower industrial digital transformation, and achieve commercial landing in multiple benchmarking industry applications.
In the more than two years of 5G commercialization, China Telecom's business growth rate is higher than the industry average. As Wang Guirong, general manager of The Science and Technology Innovation Department of China Telecom, said in a previous interview with C114, "China Telecom's leadership in the 5G era is inseparable from innovation. "This also conforms to the fact that in the first phase of China Telecom's science and technology innovation action plan, the contribution of scientific and technological innovation to revenue growth is more than 70%.
"The core of all scientific and technological innovation depends on people." Wang Guirong stressed that China Telecom is embarking on building a talent team with an alienated competitive advantage, on the one hand, by introducing core high-end talents to strengthen the research and development capabilities of the R&D team; on the other hand, actively promoting the transformation of the group's internal operation talents to R&D, IT talents to cloud network talents, and the proportion of R&D personnel will account for more than 15% by 2025. "With such a team, I believe that China Telecom's scientific and technological innovation can turn a new page." (C114 Water Easy)