5G millimeter wave core is multi-beam array
'5G millimeter wave, the goal is to achieve N multiplied by 10 Gbps transmission rate. ' Hong Wei said, 'The United States adopted 28GHz, our country is still seeking advice.'
An important technology in 5G millimeter wave is the multi-beam system of narrow beam antenna. Through this system, the gain of the communication network on the base station side is improved. The high gain of the network is the basis for achieving high transmission rate.
MIMO (Multiple Input Multiple Output Antenna Array) is a multi-beam system.
Hong Wei said that there are many types of multi-beam arrays, there are pure digital multi-beams, and passive multi-beams. At present, many large manufacturers are doing phase-controlled multi-beams. 'I think, in the end, you can't use such a structure, and the application is full. Digital multi-beam array. 'Hong Wei said, 'phase-controlled multi-beams face complexities, high cost and power consumption, and reduce the coverage of millimeter-wave base stations. This multi-beam structure can be used for transitions, but In the end, a pure digital multibeam system must be used.
At present, through Hongwei's experiment, the 28GHZ 64-channel multi-beam array has been able to support 50Gbps transmission rate, and the spectrum utilization rate exceeds 100%. Hong Wei also uses hybrid multi-beam, but his hybrid scheme is at the level. The direction uses pure digital multi-beam, and the passive multi-beam is used in the vertical direction. 'This may become an alternative or supplement to the multi-beam array. ' Hong Wei said.
However, this solution is still in the laboratory stage, and the prototype is launched. 'The final commercial product, the whole system in the laboratory should be compressed into a thin plate shape, which is convenient for integration and installation, and can also make work. The consumption, volume, weight and cost are greatly reduced. In this process, one must solve the multi-channel millimeter wave transceiver chip, and the second is to realize the antenna integration.
How to realize millimeter wave on the terminal
How does the millimeter wave terminal do? Hong Wei said that the millimeter wave is similar to the optical device. For example, the camera on the mobile phone must be exposed outside, and the millimeter wave is also the same. If the cell phone case is used, the signal attenuation is obvious unless it is low. The damage material is made of shell. The millimeter wave realizes a multi-channel millimeter wave chip on the terminal, and the antenna of the mobile phone is integrated into the chip during packaging, becoming an integrated module. 'For the designer of the mobile phone, it is like a resistor. Or a capacitor-like component, which has certain requirements at the same time, such as not being blocked by a metal frame.
On the mobile phone, where should the millimeter wave be placed? Hong Wei said, we think the best location should be in the upper right corner of the phone. Even if someone crosses the phone to watch the video and play the game, this position will not be Hand occlusion. 'Of course, there are some problems to be solved, such as antenna design, wide-angle multi-beam coverage, etc.' Hong Wei said, 'There is still a key issue here, that is, the chip must integrate all the transmission and reception information of multiple channels. . He also suggested that mobile terminal companies open interface definitions or develop uniform interface standards.
Hong Wei said that this integrated module solution looks difficult, but to achieve multi-channel 5G millimeter wave chip, there is no other way to choose, this is the only way that must be solved.
Whether it is a 5G millimeter wave base station or a terminal, to achieve miniaturization, low cost, low power consumption, it is necessary to break through single-chip integration, and to achieve mass production and packaging, Hong Wei said, for the base station, considering For power and thermal issues, antennas and chips are recommended for integration at the board or system level; for terminals, package integration or board level integration is recommended.
At present, automotive radar has made an open circuit for millimeter-wave chips. It uses multiple smaller chips to realize multi-channel. Three transmitters and four receivers in the chip operate at 71 GHz. 'We used to think that millimeter-wave chips above 40 GHz The package can't be solved. In fact, this car radar chip has already been opened, and it can be mass-produced in the same way as the low frequency band. 'Hong Wei said, 'If the chip can successfully solve the problem of multi-channel and antenna package, 5G millimeter wave The terminal can be implemented. '
5G millimeter wave can be used for low-altitude communication
The possible application space for 5G millimeter waves is low-altitude communication. Hong Wei said that China is building a satellite communication network integrating air, space and sea. One way is to transform the medium and low-orbit satellites into 5G millimeter wave base stations. Beam coverage. This approach can cause problems, such as whether the baseband processing should be placed on the ground or satellite, because multi-beam will bring a very large amount of processing, if placed on the ground will bring delay; Whether the volume, weight should be further reduced, how to achieve dynamic tracking between the stars, etc.
The 5G millimeter wave base station covers a distance of about 200 to 300 meters. From a low-altitude perspective, this is a space that is frequently used. The fast-developing drones often fly at this height. The network for the drone is also 5G millimeter waves. The application space that can be expanded. 'If we put the millimeter-wave multi-beam base station on the drone and then cover it to the ground, multiple drones can be networked, which can realize dynamic tracking between unmanned aircraft and millimeter wave broadband transmission. 'Hong Wei said, 'The UAV can be equipped with a high-powered camera, and the image back-transmission requires a large bandwidth.'
According to Hong Wei, the 5G millimeter wave working group established last year identified several research tasks: one is 5G millimeter wave application scenario, system, architecture standard; the second is 5G millimeter wave channel characteristics, spectrum planning; the third is 5G millimeter wave quality Method, performance specification; Fourth, 5G millimeter wave chip, device and process; Fifth, tissue millimeter wave package technology.
'Currently the second research mission - 5G millimeter wave channel characteristics and spectrum planning, has preliminary results, and released the first edition of the white paper. ' Hong Wei said, 'At the end of the year we hope to include 5G system architecture, standards, Measurements, chips, and packaging, etc., can be published in white papers to promote the development of 5G millimeter waves.