Architecture is the "skeleton" of the city, and technology empowers the building, which will make the "skeleton" of the city healthier and smarter, so that the city will be full of vitality. With the deep integration of next-generation information technologies such as the Internet of Things, cloud computing, big data, and artificial intelligence with the real economy, the construction of smart cities has ushered in a golden period of development, and the smart construction industry will also usher in new development opportunities.
“The vision of 5G allows information to come at your fingertips and everything is within reach. This is also the vision of smart buildings.” Zhou Feng, deputy chief engineer of the Tyre System Laboratory of China Academy of Information and Communications Technology, said in an interview with a reporter from Science and Technology Daily that 5G can After strengthening the underlying nervous system of the entire smart building and increasing the basic "soil fertility", various application scenarios will surely grow rapidly.
High frequency, large bandwidth, precise positioning
The characteristics of 5G millimeter wave are more suitable for smart buildings
Nowadays, new concepts and technologies such as building information model (BIM), geographic information system (GIS), intelligent construction, intelligent operation and maintenance, Internet of Things, and blockchain are increasingly appearing in the implementation of real estate infrastructure projects.
Some people believe that, compared with traditional buildings, the biggest feature of smart buildings is the installation of smart devices and the mining and integration of data and information. But in the opinion of Meng Tao, a senior expert in Alibaba's smart building division, smart buildings are not simply buildings grafted with digital technology. A smart building is a building with an operating system, a new life form with comprehensive perception and always online, and an open ecosystem that deeply integrates humans, machines, and objects.
The key technology behind smart buildings is the ubiquitous network connection. "On the basis of the connection between people and equipment in the venue, smart services that integrate multi-dimensional resources can transform traditional office buildings into smart buildings." Meng Tao said.
So, how should 5G networks in smart buildings be deployed? It is understood that the global 5G deployment is based on two major types of frequency bands, one is the sub-6GHz frequency band (Sub-6GHz), and the other is the millimeter wave frequency band (30GHz-300GHz).
Compared with the Sub-6GHz frequency band, the biggest advantage of millimeter wave is that the frequency band resources are very rich, the bandwidth can reach 400M or even 800M, and the wireless transmission speed can reach 10Gbps. In addition, the millimeter wave can integrate more antennas to form a narrower beam, and the spatial distribution capability is very strong. At the same time, due to its large bandwidth, the resulting air interface delay is small, which provides a natural advantage for the development of highly reliable and low-latency services. Relevant experts believe that millimeter waves can provide unprecedented support for new applications that were difficult to support in the past by mobile technology, and its indoor coverage will become the primary research direction of smart buildings.
From face access control, smart visitors, video conferencing, multi-screen linkage, wireless projection, one-click WiFi, cloud printing, to smart parking, smart lighting control, air quality detection... Zhou Feng believes that smart buildings are embedded with many high Technological software and hardware, network terminals may be tens of thousands, requiring ultra-large bandwidth and extremely high data transmission rate, and the characteristics of millimeter waves can meet this demand; secondly, the beam of millimeter waves is very narrow and the antenna size is the same. It is narrower than the microwave, so it has good directionality, can distinguish small targets closer or observe the details of the target more clearly, so it can better realize such as wayfinding, space scheduling and access control based on mobile credentials And other architectural functions.
At the Mobile World Congress in Barcelona in 2019, Qualcomm of the United States conducted a special test on the application of 5G millimeter wave indoor scenes. The results showed that the use of millimeter waves can provide very high bandwidth in indoor scenes with high user density. Smartphones, laptops and other networked terminals bring high-capacity, multi-gigabit transmission rates and low-latency connections.
At the same time, my country's 5G millimeter wave indoor coverage test is also being carried out quickly. At the "World 5G Conference" at the end of November this year, China Unicom also revealed that China Unicom has already conducted millimeter wave trials in some venues. In some venues in Beijing, millimeter wave technology can achieve a peak rate of 9Gbps. Provide safe, reliable, convenient and high-quality network services for the venues, and provide the audience with a super live interactive experience.
Small base station, optical carrier radio frequency, "one floor, one policy"
These methods can solve the problem of millimeter wave indoor coverage
Despite the attractive prospects of the millimeter wave indoor coverage market, it is not easy to apply millimeter waves to achieve terrestrial 5G network coverage. Radio waves have a characteristic, that is, the higher the frequency spectrum, the worse the diffraction ability. Millimeter waves are super high-frequency radio waves with relatively small coverage radius. Therefore, operators need to build very dense 5G base stations and pay high costs. There is still a long way to go before applying millimeter waves to build terrestrial 5G networks to achieve Sub-6GHz coverage.
For example, Zhou Feng, a paper published by the Huawei Shanghai Research Institute shows that the measurement results show that it is very difficult for millimeter waves to cover indoors from outdoor macro stations. Only in the direction close to the base station can there be better coverage, and there is almost no coverage in the depth.
"In past studies, we have seen that it is very difficult for 5G millimeter waves to cover indoors from outdoors. Compared with 3.5GHz band signals, after removing the increase in free space propagation loss, the penetration loss of millimeter waves in buildings is higher than in some scenarios. The low frequency range is 6 to 16 decibels." Zhou Feng said.
In 2019, U.S. telecom operator Verizon conducted 5G millimeter wave coverage trials in Chicago and Minneapolis, and found that its transmission rate in outdoor scenarios was very high, and once it entered indoors, the transmission rate dropped significantly, even Slower than 4G network.
Zhou Feng pointed out that from previous tests conducted by the China Academy of Information and Communications Technology, it is very difficult to use outdoor macro base stations to achieve millimeter-wave indoor coverage in certain scenarios. For example, for energy conservation and consumption reduction, many buildings have used a large number of metal-coated thermal insulation glass. And this kind of glass has a very strong electromagnetic wave blocking effect, which makes it very difficult for millimeter waves to cover indoor signals from outdoor base stations. "This requires the use of a joint network of high frequency and low frequency bands. In 5G indoor coverage, different building structures are used. Achieve'one floor, one policy'."
"In the future 5G architecture, the outdoor and indoor scenes will be separated. Large spaces with few indoor partitions, such as the convention and exhibition center scene, will have no problem with millimeter wave coverage. Advanced and intelligent smart buildings can be built on such a physical basis. Information system, and the cost can be more clearly estimated." Zhou Feng said.
In an experiment conducted by Qualcomm in 2019, indoor network coverage basically abandoned the idea of setting up base stations outdoors, instead using a large number of 5G millimeter wave small base stations, such as 10 5G millimeters in a 15,000-square-meter terminal building. Wave's small base station can achieve efficient network coverage.
How to solve the indoor propagation environment with physical partitions? "In addition to fully considering the deployment of small base stations from the perspective of architectural design, radio-over-fiber will also play an important role." Zhou Feng said that radio-over-fiber communication is a technology that combines optical fiber and microwave, which can use low-loss and low-loss optical fiber. The characteristics of ultra-wideband and anti-electromagnetic interference to transmit wireless signals can effectively solve the bandwidth and transmission distance requirements of the next-generation ultra-wideband wireless access, while also effectively reducing network costs.