Communication is the main downstream application field of PCBZ. According to prismark's data, communication accounted for 27.30% of the total output value of PCB in 2017 and is the largest downstream application field of PCB. PCB is widely used in wireless network, transmission network, data communication and fixed network broadband, and is usually a product with high added value such as backplane, high-frequency high-speed board and multilayer board. 5g is the next generation mobile communication network. At that time, there will be a large number of infrastructure construction needs, which is expected to greatly boost the demand for communication boards.

　　The number of 5g base stations is expected to increase significantly. The peak rate of 4G is 100Mbps to 1Gbps, while 5g will provide bandwidth above 10Gbps, 1ms delay and ultra-high density connection, with mobility of 500km / h and traffic density of 10Mbps / m2. At present, China's three major operators have entered the big acceleration stage of 5g construction, and have launched pilot projects on 5g scale test and application test. Local governments have set 5g coverage schedules and accelerated infrastructure construction to achieve the goal of large-scale commercial use in 2020.

　　Because 5g requires massive connections, the number of base stations in 5g era will increase greatly compared with 4G era. By the end of 2017, the number of 4G macro base stations in China has reached about 3.6 million, while the planning of 5g macro base stations of the three major operators is 1.5 times that of 4G, and the total number has reached about 5.4 million. 2019-2023 will be the peak period of 5g base station construction.

　　5g will also drive the construction of tens of millions of micro base stations. Due to the high frequency spectrum used by 5g communication, a large degree of attenuation will occur in the propagation process. Therefore, micro base stations need to be used as a supplement to macro base stations to realize ultra dense networking. According to the prediction of CCID consultant, the number of 5g micro base stations is expected to be 4 ~ 5 times that of macro base stations, corresponding to about 25 million micro base stations.

　　5g will bring significant changes to the base station structure, and the consumption and unit price of communication PCB are expected to increase significantly. In the 4G era, a standard macro base station is mainly composed of baseband processing unit BBU (base band unit), radio frequency processing unit RRU (remote radio unit) and antenna. Since the 10Gbps transmission capacity of the traditional CPRI (public radio interface connecting RRU and BBU) is not enough in the 5g era, the 5g base station structure needs to be reconstructed in order to reduce the transmission bandwidth.

　　In the 5g base station, due to the need to use the massive MIMO antenna, the functions of some BBus are combined with rrus and antennas to form a new active antenna unit AAU (active antenna unit). The remaining BBus are divided into cu-du two-level architecture, in which du (distributed unit) is a distributed unit, which is responsible for meeting the real-time requirements and has some underlying baseband protocol processing functions; Cu (centralized unit) is a central unit with non real-time wireless high-level protocol processing function.

　　The antenna array of 5g base station needs to use PCB as the connection. Compared with the PCB in 4G era, the PCB used in 5g will be upgraded in many aspects, resulting in a significant increase in consumption and value.