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.

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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.

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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.

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In the age of5g, the increasing number of antenna channels and the active antenna have put forward higher requirements for antenna design. Miniaturization and lightweight are the basis.

In4Gera, the antenna configuration is basically 4t4r (FDD) or 8t8r (TDD). According to the current test situation, the5gera may be dominated by 64t64r large-scale array antenna.

The number of channels has increased by 7-15 times year on year, which means that the demand for RF devices of antenna has increased by 7-15 times year on year. At the same time, the passive part of antenna will be combined with RRU into AAU, which puts forward higher design requirements for the volume and weight of antenna in5gera.

In the4Gera, the weight of passive antenna + RRU is about 24-34kg, and the weight of 5gaau in the current test is about45kg, with a year-on-year increase of 32% - 88%. Therefore, in the trend of5gantenna integration, miniaturization and lightweight become the basis of antenna design.

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Large scale array antenna drives a substantial increase in demand for RF components

As mentioned above, we expect that5gcommercial Acer station will be dominated by 64 channel large-scale array antenna. The antenna unit mainly consists of radome, radiation unit and calibration network integrated board.

From the current research and development status of5gproducts, in order to achieve new technologies such as beamforming, we predict that 64 channel antenna array will accommodate 64 power amplifiers, 64 switches, 64 PLLs, 64 low-noise amplifiers, 64 filters and other devices in the future.

We believe that the improvement of the demand for RF components will greatly enhance the market space of the base station RF industry, and the high integration demand will also promote the further upgrading of filter, power amplifier and other RF component technologies, and the products will be more miniaturized.

Write By WHWIRELESS