Massivemimo, that is, large-scale MIMO (multiple input multiple output) technology, aims to greatly improve network capacity and signal quality through more antennas. In principle, it can be compared with Expressway to expand the number of roads to improve traffic flow. The 5g base station with massivemimo can not only improve the network capacity by multiplexing more wireless signal streams, but also greatly improve the network coverage capacity by beamforming. By adjusting the spatial distribution of antenna gain, beamforming technology makes the signal energy more concentrated to the target terminal when transmitting, so as to make up for the loss of spatial transmission after signal transmission and greatly improve the network coverage. Compared with 4G base station, AAU supporting large-scale array antenna technology is the main reason for the significant increase of5gbase station cost. Screenshot9.21.43 amFebruary 28, 2019 Antenna size is related to frequency,5gantenna or 64 channel antenna According to the principle of wireless communication, in order to ensure the highest conversion efficiency of antenna transmission and reception, the distance between antenna oscillators must be greater than half of the wireless signal wavelength, and the wireless signal wavelength is inversely proportional to the wireless signal frequency (λ = C / F, where C is the speed of light, f is the wireless signal frequency), that is, the higher the signal frequency, the smaller the signal wavelength. In the future,5gfrequency band inChinawill be mainly 3.5GHz and 2.6GHz. According to this frequency band, half of the wavelength is about4.3cm/5.8cm. According to the current5gtest, the 64 channel massivemimo technology is the mainstream test choice of various equipment manufacturers. Although the more channels, the higher the performance of the network, but considering the size / weight of the antenna, antenna performance and cost factors, the current operators are also considering the low-cost massivemimo scheme - 16 channels. In our opinion, if the cost of 64 channel antenna in the early stage of5gis not reduced to the range accepted by the operator, the operator may give priority to the 16 channel scheme when the deployment and capacity are met. Screenshot9.23.33 amFebruary 28, 2019 The5gbase station architecture has changed greatly, and the trend of antenna active is obvious 4GHongji station is mainly divided into three parts: antenna, RF unit RRU and baseband processing unit BBU deployed in the computer room. 5gnetwork tends to adopt the new wireless access network architecture of AAU + Cu + Du, as shown in the figure below. The antenna and RF unit RRU will be combined into a new unit AAU (active antenna unit). Besides RRU RF function, AAU will also include some physical layer processing functions. Screenshot9.24.35 amFebruary 28, 2019 In the age of5g, the increasing number of antenna channels and the active antenna have put forward higher requirements for an...

Intelligent parking system NB IOT version. The new version includes Internet of things data detection unit (IDU), Internet of things operation management platform (IOP) and supporting mobile app. The system perfectly meets the needs of road parking and open park parking scenes, effectively solves the problems of road parking fee management, parking in the park to find parking space, and promotes the intelligent and scientific urban parking. Intelligent parking system has four highlights. The first is technology leadership. Based on the new Internet of things technology NB IOT, the system has the characteristics of low power consumption, wide coverage, multi connection, low cost, high accuracy, etc. the access capacity is improved by more than 50 times, and the stable access and reliable data transmission of the system are realized. The vehicle detector uses advanced geomagnetic detection technology to determine whether the parking space is occupied by sensing the change of magnetic field, and the detection accuracy is more than 99%. Secondly, it is easy to use. The system supports parking space reservation, parking guidance and multi-channel payment to realize convenient parking. Users can query the real-time information of parking spaces through the system supporting mobile app, and reserve the spare parking spaces according to the information. Then the parking guidance function will guide the owner to find the parking space quickly. After the completion of parking, users can choose the payment methods such as app self-service payment, auto deduction of car tag or manual payment according to their own conditions to pay the parking fee. In addition, the operation and maintenance of the system is simple. The equipment has small volume, easy installation, strong anti-interference ability and long service life. All wireless network architecture , supporting remote maintenance and upgrading. Fourth, efficient operation and maintenance management. Relying on the powerful data mining technology, the management system can effectively integrate the massive parking data and realize the unified planning and management of parking resources. At present, the system has been tested in Shenzhen,Nanjingand other places, and will be expanded to more cities around the world in the future. According to statistics, after the deployment of the system, the parking congestion rate will be reduced by 12%, the time to find parking space will be reduced by 43%, and the parking management income will be increased by 30%, bringing better economic value and social benefits. BY  WHWIRELESS

There is a popular saying about Urban Governance: sewer is the conscience of a city. In the city, there are all kinds of densely distributed pipe networks underground, which are used for sewage discharge, drainage, various pipeline laying, etc. In these pipe networks, a node is the well cover we can see, walking in the road, sidewalk, park, community, factory and other environments. However, due to the lack of effective real-time monitoring and management means, a large number of manhole covers provide opportunities for lawbreakers. Illegal activities such as moving and stealing the manhole covers occur from time to time. At the same time, when the manhole covers are loosened, sagged or the surrounding concrete structure is cracked due to the inherent construction problems and the continuous rolling of passing vehicles every day, it becomes a human being The "trap" of fear. Due to the large number of urban well covers, in order to better ensure the safety of public facilities and protect the main underground resources, it is urgent to adopt new technology and new mode to strengthen the safety management of well covers. With the rapid development of Internet of things technology, the concept of smart city was born based on the combination of satellite positioning, mobile communication and cloud computing. Along this development direction, the traditional municipal infrastructure was transformed to make it intelligent and Internet of things, improve the level of urban governance, and promote the construction of smart city. For a small well cover, the well cover monitoring system based on Lora / ZigBee transmission has been widely used without changing its physical properties and use. The intelligent hardware is installed on the common well cover to realize the intelligent upgrade, which makes the well cover visible, controllable and manageable, and becomes the front guard of urban pipe network monitoring. It can realize the monitoring and management of the intelligent well cover. There are various ways of data communication between the up and down lines, which can be transmitted by wireless way: ■ network port, connecting the server of well cover management center; ■ 4G, connect the Municipal Center Management cloud platform, and the operation and maintenance administrator mobile app; ■ RS485, which can be connected to other acquisition bottom instruments, sensors and IOT equipment; ■ Lora / ZigBee, to monitor the terminal status of intelligent well cover (optional module, one out of two); ■ after the installation of the client program, it can be used directly, fully meet the various functional interfaces, and avoid the trouble of hardware development and system transplantation. Intelligent well cover monitoring management process ❶ when the well cover inclines 10-15 ° or the well cover shifts, the detection signal will be sent out when the water level exceeds the limit; ❷ the detection signal is transmitted to the intelligent gateway through Lora ...

How many base stations are built? It depends on the wavelength of electromagnetic wave. The longer the wavelength, the less the base station and the less the investment. However, the longer the wavelength, the less information and data it carries, and the lower the transmission efficiency. Therefore, mobile communication is developing in the direction of shorter wavelength. So, what is the wavelength of5G? This is determined by the formula: the speed of light = wavelength * frequency. The speed of light is constant. It is300,000 kmper second. The frequency of5Gis 24 gHz-32 gHz. According to the calculation of 28gHz, the wavelength is about108 mm. Therefore, 5G communication belongs to millimeter wave communication. Its advantages are large transmission bandwidth, high transmission efficiency, but its disadvantages are short transmission distance and easy to be blocked. The cost is high. Compared with4G, the transmission efficiency is improved by hundreds of times, but the expansion of base station alone is increased by more than 20 times. At present, the construction density of 4G base stations in cities has basically achieved 500 meters, while in some urban central areas, it has reached 200-300 meters, and even in some areas, the density of base stations can even reach 100 meters. The two main reasons are as follows: first, there are too many high-rise buildings in the city, and the obstruction is serious, so we have to build more base stations; second, the population density in the city is much larger than that in the rural suburbs, considering the user perception, we also have to build more base stations. In fact, the biggest problem of 5G coverage is still on the upstream, as well as indoor coverage. Because of the high frequency of5G, the indoor coverage effect will be worse than the current4Gcoverage, which is why the user experience speed ofKoreaand theUnited Statesis not so fast after5Gcoverage. In fact, the reason why5Gwants to build more base stations in cities is not to say that the city's macro base stations. Now the density of4Gmacro base stations in cities is large enough. Maybe more is to build some indoor 5G base stations. In rural areas, there are fewer high-rise buildings and fewer barriers, so there is no need to build a base station with the same density as a city.                                                                                                                                              Write By  WHWIRELESS