Build 5g microwave back to become a sharp weapon Expected to finish reading in 8 minutes From a global perspective, microwave back propagation has become a mainstream way of back propagation. In 2017, sky light research, a third-party market research institution, published the article "5g retransmission, microwave surpasses expectations". It points out that 50% - 60% of mobile base stations in the world are retransmitted by microwave at present. With the acceleration of 5g deployment, the network capacity, complexity and delay requirements are higher, and the number of mobile base stations will increase. Microwave is an important transmission method in the fiber-free scenario, With the evolution of 5g, it will continue to expand. Ericsson microwave outlook released in 2018 mentioned that the solution of optical fiber and microwave integration is the mainstream way of 4G evolution and 5g return. By 2023, the 40% base stations will be back to wireless transmission. If China, Chinese mainland, Taiwan, Korea and Japan are excluded, the proportion of wireless backhaul will be as high as 65% by 2023, because there are a large number of 4G base stations in Northeast Asia, and their return depends mainly on optical fiber, which will reduce the proportion of global wireless backhaul. As mentioned in the report 5g wireless return issued by ETSI in November 2018, wireless return technology has been applied to 50% of base station connections in the world, and it is obvious that wireless return has become an important scheme for 5g rapid deployment and economy. There are some shortcomings in microwave transmission mode, mainly sight distance transmission, and when there is too much moisture or dust in the air, the quality of microwave signal will be reduced. Of course, this does not affect the share of microwave echo in overseas market. It can be seen that the 4G era microwave echo is the mainstream echo mode, and the 5g era will continue this mode. However, the inherent characteristics of 5g challenge the microwave return, such as the increase of bandwidth, the scarcity of public frequency band, and the strictness of network experience. Previously, the global microwave return mainly used the 6-42ghz band, with an average return capacity between 50Mbps and 500mbps. Obviously, this is unable to meet the demand of base station return capacity in 5g era. Therefore, E-band begins to appear, i.e. 70ghz-80ghz band. E-band really provides a strong support for 5g's return. In May 2019, Deutsche Telekom and Ericsson cooperated to achieve 100gbps return rate on the 1.5km E-band microwave link for the first time, which is 10 times of the current commercial microwave return rate and can meet the demand of 5g return. Huawei occupies the largest share of the microwave transmission market, with a 29% share in the fourth quarter of 2019. Earlier, Ren Zhengfei mentioned in an interview that "there are not many microwave manufacturers in the world, and Huawei is the most advan...

Theory and application of high precision positioning Expected to finish reading in 12 minutes From mobile Internet to Internet of things, location is a basic and indispensable information, but from the refined industry application requirements, only higher precision location information can bring higher value, people can more accurately know the location of things, know the specific location of people, and better manage enterprises, personnel or materials. For example, to ensure the personal safety of tunnel construction personnel, to assist the prison to build a global and visual supervision platform; to improve the safety assurance efficiency of the petrochemical industry; to help upgrade the intelligent management of the construction site. However, the above industries have high requirements on ultra-high positioning accuracy, large capacity, low delay and high refresh rate. Location and navigation technology is responsible for providing real-time motion information of carrier (such as autonomous vehicle), including carrier position, speed, attitude, acceleration, angular speed, etc. Autopilot often adopts the way of multi-sensor fusion positioning. This paper mainly introduces the application of IMU in automatic driving positioning. Working principle of high precision positioning At the perception level of unmanned vehicle, the importance of positioning is self-evident. Unmanned vehicle needs to know its exact position relative to the environment, and there can be no more than 10cm error in positioning here. GPS can provide absolute positioning of meter level for vehicles, differential GPS or RTK GPS can provide absolute positioning of centimeter level for vehicles, but not all sections can get good GPS signals at all times. Therefore, in the field of automatic driving, the output of RTK GPS is generally integrated with the sensors of IMU and automobile (such as wheel speedometer, steering wheel angle sensor, etc.). The full name of IMU is inertial measurement unit, which is usually composed of gyroscope, accelerator and algorithm processing unit. Through the measurement of acceleration and rotation angle, we can get the self motion track. We call the traditional IMU and the system combined with the vehicle body, GPS and other information fusion algorithms as the generalized IMU for automatic driving. The emergence of this technology makes up for the lack of GPS positioning, and the two complement each other, enabling autopilot to get the most accurate location information. At present, the most widely used positioning method of unmanned vehicle is the integration of global positioning system (GPS) and inertial navigation system (INS). Integrated navigation involves complex coordinate system transformation, which requires initial calibration of the inertial navigation system. Generally, the reference navigation system (such as GNSS) is used to give the inertial navigation system an initial position value (the purpose is to establish the initia...

How much imagination can 5g network bring to industry? Expected to finish reading in 8 minutes 2020 is not only the year of outbreak, but also the first year of5gcommercial operation.5G, as the key of a new round of industrial revolution, according to the characteristics of ultra-high bandwidth, low latency and ultra large connection, will have a significant impact on human society. The first is to meet the needs of digital life, such as high-definition video, virtual reality VR and AR of augmented reality; the second is to meet the needs of digital society, such as smart city, environmental monitoring, intelligent agriculture, etc.; the third is the digital industrial demand, remote control and automatic driving of the factory. Ubiquitous demand and rigid demand As we all know, the industrial control network and management network of the traditional manufacturing plant belong to the internal network. We can understand it as a closed network, after all, the outside world is inaccessible. With the spread of the concept of industry 4.0, the development and application of domestic intelligent manufacturing, the factory needs internal network and external network for interconnection. From the actual situation, the manufacturers of textile, toys, food packaging and other industries tend to develop in the direction of flat internal communication network and functional architecture. Industry insiders said that the existing industrial wireless solutions can not meet the needs of intelligent factories, and the only hope is5G, while some traditional factories have to adopt the industrial scenario of wireless communication when they are transforming and upgrading. For example, it is very inconvenient to reconstruct the old factory wiring; the production sites in oil production, oil and gas pipelines and other fields are too far away, as well as the operation sites with poor environment such as corrosion and salt fog. How can5gmake production and manufacturing more optimized? Since it is industry 4.0, it is different from labor-intensive production and manufacturing. The use of robots and the collaboration between machines are the main scenes. The traditional industrial communication adopts the master-slave mode, and realizes the communication between the machine and the machine through the main control equipment such as PLC. The application of5gwill greatly improve the communication between machines and make them more efficient. In terms of factory logistics,5Gmakes it possible for logistics distribution vehicles in the park and plant area to realize automatic driving. In terms of remote operation and maintenance of large-scale manufacturing equipment,5gcan transmit more unstructured data, such as video, which can quickly understand the situation of the industrial site, and can quickly feedback the situation when operating the machine. In the future, no or few people factories need a lot of on-site data for decision-making support. The characteristics of ul...

Characteristic difference between PCB and FPC Expected to finish reading in 8 minutes Printed circuit board (PCB) On the insulating base material, a printed board for connecting and printing components between points is formed according to the predetermined design FPC (flexible printed circuit board) Printed board made of flexible base material. It is one of printed boards PCB is now an indispensable component in electronic equipment. PCB has different structures and uses, but there are many kinds. PCB can be divided into rigid board and flexible board according to the mechanical properties of whether the substrate can be bent, and rigid flex combined PCB (R-FPC) between them; moreover, PCB can be divided into single panel, double-sided board and multilayer board according to the number of conductive layers. Flexible printed boards (FPC) include conventional printed boards and IC packaging carrier boards (COB: chip on Flex). At the same time, FPC also has single panel, double-sided board and multi-layer board. At present, there are two kinds of multilayer boards: conventional through hole interconnection multilayer board and multilayer multilayer board (HDI board). FPC also has two kinds of multilayer boards with different structures and processes. FPC circuit board and PCB comparison, PCB is printed circuit board or printed circuit board, or printed circuit board. FPC is the abbreviation of FPC, also known as soft board, which is a hard board and a soft board. PCB consists of soft board and hard board, but most of them are hard. And FPC is mostly used for lines that are easy to fold, such as cell phone cable and LCD cable. FPC is used for soft light strip, and its folding resistance must be much stronger than PCB. Characteristics difference between soft board and hard board In fact, the soft board is not only flexible, but also an important design method of connecting three-dimensional circuit structure. This structure, together with other electronic product design, can widely support various applications. So from this point of view, soft board and hard board are very different. For the hard board, unless the circuit is made into a three-dimensional shape by means of mold filling, the general state of the circuit board is plane. Therefore, to make full use of the three-dimensional space, the soft board is one of the good plans. In terms of hard board, the common space extension scheme at present is to use slot plus interface card, but the soft board can complete similar structure with transfer design, and the direction adjustment is also relatively flexible. Using one connecting soft board, two hard boards can be connected into a group of parallel line system, or can be turned into any angle to adapt to different product shapes. The soft board can be connected by terminal connection, but the soft board can also be used to avoid these connection mechanisms. A single soft board, you can use the layout to configure many hard boards and connect them...