The communications industry is in an exciting period of innovation and change. Among them, the mobile Internet can be said to be one of the most eye-catching hotspots in this round of change. The emergence of a series of smart terminals and the popularization of 3G have enabled all ordinary people to truly realize their dream of accessing the Internet anytime, anywhere. Supported by 3G networks, people can not only obtain information through smart terminals, but also realize many functions that were unimaginable in the past, such as video browsing, location services, and online games. According to the analysis data of Bell Labs, by 2014, there will be 1.2 billion connected mobile terminals represented by iPad and 2.5 billion smartphones in the world. The data growth brought by all these terminals is explosive. According to statistics, the monthly data flow of smartphones is 35 times that of ordinary feature phones, and the data flow of a tablet computer is 121 times that of ordinary mobile phones. Laptops with internet cards The traffic volume has even reached 498 times that of ordinary mobile phones. Driven by these new intelligent terminals, mobile Internet services will account for 70% of all mobile data by 2014; by 2015, the total amount of mobile data will be 30 times that of 2010; by 2017, there will be global The 107EB data comes from various mobile terminals. Therefore, some people vividly say that we are facing a data tsunami. Is our basic network ready to respond? The response of optical network As the basic network, the optical network needs to be prepared in advance for the growth of bandwidth. At present, the evolution of the optical transmission network from today's 10G, 40G to 100G has become unstoppable. From the statistics of InfoneTIc, we can see that by 2014, the number of shipments of 100G boards based on coherent detection technology will account for 40% of all rates. Judging from the current situation, the 100G standard is fully mature. IEEE, ITU-T, OIF and CCSA have fully defined the 100G system architecture, module interface, link standard, and equipment technical specifications and test specifications. In various fields such as routers, optical transmission, optical modules and test instruments, there are already many manufacturers that can provide mature commercial products. Therefore, it can be said that the entire ecosystem of 100G is very perfect. Compared with the diversity of 40G encoding methods, the technical route of 100G is quite clear. The industry recognizes that PDM-QPSK + coherent detection is the best solution for 100G. However, 100G is not the end point of optical network bandwidth evolution. At present, various manufacturers have begun to carry out research on 400G or even 1T systems. But from Figure 1, we can see that the research and development of systems above 100G face the limitations of Shannon's law, and must balance spectrum efficiency, performance, and capacity. As shown in Figure 1, if the modulation phase is developed from 4 phases commonly used in 100G to 16 phases in 400G, the OSNR requirement of the system will increase by 3.8dB; if it is further increased to 256 phases, the system OSNR will reach more than 19dB, which Undoubtedly, the transmission distance of the system will be greatly shortened. If we want to achieve 400G or even T-bit transmission, we can make improvements in the following areas. 1. Higher performance DSP processing chip. It gives us the ability to introduce SD-FEC. Compared with HD-FEC, it can roughly improve the system OSNR performance by about 1.5dB, that is, the purple dot in Figure 1 pushes the limit of Shannon curve by 1.5dB. Of course, SD-FEC will bring more overhead bytes, higher cost and longer delay. We need to adopt it flexibly according to the actual needs of the network. For 100G systems, HD-FEC-based technology can already achieve 2000 kilometers of relayless transmission, which can meet the needs of most networks; but for systems above 400G, SD-FEC is a must-have technology. 2. Flexible grille technology. The transmission rate after 100G generally requires a frequency spectrum greater than 50GHz. For example, 400G adopts dual carrier frequency and 16-phase multiplexing. The theoretical spectrum bandwidth is 100GHz. After some technical processing, the spectrum bandwidth can be compressed to 75GHz, which brings about a problem of how to effectively arrange signals of different spectrum widths in the C-band. The flexible grid technology defines a minimum spectral width of 12.5 GHz, allowing different signals to be flexibly arranged in this unit, thereby maximizing spectrum utilization. 3. Raman light put. Raman optical amplifier is not a new technology. We need to obtain a better system OSNR when marching to the rate above 100G. The low noise figure of Raman optical amplifier is very helpful for this. 4. Super channel. By modulating several 100G signals together, a T-bit high-speed signal can be obtained. Usually these sub-signals are modulated by OFDM to obtain the best spectral efficiency. Since each sub-signal is a 100G channel, the 100G DSP and related processing technology can be regarded as a basic module for building higher-rate signals. 5. Advanced power control technology. As we all know, higher fiber input power can bring better OSNR performance, but at the same time will bring greater nonlinearity. In systems above 100G, we need to better control the input power of each channel to achieve the optimal point between OSNR and nonlinearity. Alcatel-Lucent's high-speed transmission solution Alcatel-Lucent first launched a single carrier 100G related detection commercial system on the OTN platform 1830PSS as early as June 2010. So far, it has been widely used in more than 60 customer networks around the world. The cumulative number of 100G OTU shipments has exceeded 2,300, accounting for more than 69% of the global 100G market share, and it is undoubtedly in a leading position. In December 2011, Alcatel-Lucent released an enhanced 100G solution to increase the distance from electricity-free relay from 1500 km to 2000 km. In March 2012, Alcatel-Lucent once again released a new generation of photonic processing engine (PSE-Photonic Service Engine) for 100G and 400G. The engine uses the following four key technologies to further improve performance. 1. Introduce SD-FEC to improve the system performance of 1.5dB, so that the transmission distance of 100G system without electric relay is further extended to 3000 kilometers. 2. The advanced wavelength shaping technology compresses the 400G spectrum broadband to 75GHz, and can accommodate up to 58 channels in the C band, thereby increasing the maximum capacity of the system from the original 8.8T (88x10G) to 23T (58x400G) , Expanding the network capacity by 2.6 times. 3. Higher sampling rate and ultra-fast digital-to-analog conversion make the signal judgment more accurate. 4. Enhanced frequency and phase control techniques to suppress slip codes. In addition to continuously improving network transmission capacity, Alcatel-Lucent is also constantly innovating in the transmission network architecture. Alcatel-Lucent first proposed the concept of CBT (Convergent Backbone Transport), that is: try to bypass the upper layers with low layers, and use the upper layers only when necessary; try to bypass the electrical layers with optical layers, and use the electrical layers only when necessary. This is because the lower the processing level, the higher the transmission efficiency and the lower the power consumption per bit. For large-granular services such as 100G in the backbone network, because its aggregation requirements are usually already completed in the aggregation layer, the service destination is clear and single, so the optical layer scheduling based on ROADM can best achieve the purpose of efficient transmission. In the aggregation layer, in order to improve the bandwidth filling rate, ODU cross-matrix can be introduced to complete the aggregation based on small particle services. Routers are only introduced at sites that really need to open data packets for more than three layers of processing. Air Bar,Disposable Vape Air Bar,Air Bar Disposable Vape Pod,Air Bar Light Edition Shenzhen Zpal Technology Co.,Ltd , https://www.zpal-vape.com
