The most comprehensive antenna solutions for 5G scenarios (Part 1)

石榴姐

The most comprehensive antenna solutions for 5G scenarios (Part 1) [Copy link]

With the development of 5G test networks, the increase in the number of channels in 5G base station systems has not improved the perception of single users. Its main function is to increase the access capacity of multiple users, but it also increases the investment cost of network construction. In actual application scenarios, such as outdoor dense hotspot scenarios, wide-area coverage scenarios, indoor distribution scenarios, traffic arteries and tunnel scenarios, their requirements for coverage and capacity are different.

64TR/32TR is considered as the standard configuration of 5G Massive MIMO antenna, but the high complexity of antenna design, large size, high cost and other disadvantages limit its feasibility in some scenarios. So today we will share a list of antenna solutions for 4G/5G network coexistence in various scenarios. Including main macro base station, indoor distribution, high-speed rail, tunnel, etc.

5G antenna solution for main macro base station scenarios

1.1 Coverage and Rate Testing

The main macro site scenarios include coverage scenarios in densely populated urban areas, general urban areas, and rural towns. China Unicom Group conducted a comparative test on 64T & 32T high-rise building coverage, and the test results are as follows.

The dense urban area test is shown in Figures 1 and 2.

Figure 1 SSB-RSRP gain of 64T&32T high-rise coverage in densely populated urban areas

Figure 2 Downlink rate gain of 64T&32T high-rise coverage in densely populated urban areas

The ordinary urban area test is shown in Figures 3 and 4.

Figure 3 SSB-RSRP gain of 64T&32T high-rise coverage in ordinary urban areas

Figure 4 Downlink rate gain of 64T&32T high-rise coverage in ordinary urban areas

The suburban test is shown in Figures 5 and 6.

Figure 5 SSB-RSRP gain of 64T&32T high-rise coverage in suburban area

Figure 6 Downlink rate gain of 64T&32T high-rise coverage in ordinary urban area

The test results show that the coverage and downlink rate gains of 64T are more obvious in dense urban areas, with a downlink coverage gain of 4 dB and an average downlink rate gain of 40%. In ordinary urban areas or suburbs, the increase in the number of antenna channels did not achieve significant coverage and downlink rate gains.

1.2 Uplink and Downlink Capacity Simulation

The main macro site scenarios include coverage scenarios in densely populated urban areas, general urban areas, and rural towns. China Unicom Group conducted capacity simulation comparisons of 64T and 32T in the above scenarios. The simulation results are shown in Figures 7 and 8.

Figure 7 Comparison of downlink capacity gain of 64T and 32T high-rise coverage

Figure 8 Comparison of uplink capacity gain of 64T and 32T high-rise coverage

The simulation results show that the capacity gain of 64T in dense urban areas is more obvious, with the downlink capacity of 64T being 1.2~1.6 times that of 32T, and the uplink capacity being 1.1~1.2 times. However, in ordinary urban areas or suburbs, the increase in the number of antenna channels does not achieve obvious uplink and downlink capacity gains.

1.3 5G Antenna Solution for Main Macro Site Scenario

Based on the above analysis, considering the cost-effectiveness of coverage, capacity and antenna investment, in dense urban areas, 5G antennas should use Massive MIMO 3D shaped antennas with 64T/32T as the main antenna. In ordinary urban areas, 5G antennas should use multi-beam antennas with 16T as the main antenna. In rural suburbs, 5G can use ordinary antennas with 8T as the main antenna. The 5G antenna solution for the main macro base station scenario is shown in Figure 9.

Figure 9 Schematic diagram of 5G antenna solution for main macro base station scenario

a) 64T/32T 3D shaped antenna.

In densely populated urban areas, 5G antennas should adopt 64T/32T Massive MIMO 3D shaped antennas. Massive MIMO is one of the key technologies of 5G, and its key technologies are MU-MIMO technology and 3D-MIMO technology. MU-MIMO is multi-user MIMO. Multiple users in the network can use the space division channels provided by Massive MIMO to communicate with the base station at the same time and frequency resources, greatly improving the spectrum efficiency without increasing the base station density and bandwidth.

3D-MIMO technology is based on multi-array beamforming. Beamforming technology performs weighted combination of the signals of each antenna element, and then changes the weight of the antenna array, so that the beam shape and direction change accordingly, and the beam with smaller energy is concentrated in a small area. It can form narrow beams with different gains in different directions. These narrow beams can be scanned in the vertical and horizontal directions as needed, and have three-dimensional coverage capabilities.

At the same time, it can also match the corresponding beam according to the needs of business scheduling, realize flexible tracking of different terminals in the cell, and have super anti-interference ability. On the one hand, the 3D-MIMO beam has higher gain, narrower beam width, and can point to any vertical and horizontal direction according to actual needs;

On the other hand, 3D-MIMO beams can exist at the same time and form MU-MIMO beams to complete full airspace coverage. The implementation of beamforming technology not only requires more antenna arrays, but also requires the antenna to be transformed from the passive antenna with the RF processing unit separated from the antenna array to the active antenna after fusion, so as to achieve adaptive adjustment of the phase and power of each antenna array. The disadvantage is that the algorithm is complex, the large-scale antenna array increases the size and weight of the antenna, and the antenna is expensive. The advantage is that 3D beamforming technology can suppress interference while improving network coverage, improve the experience of users at the edge of the cell, and accommodate more users, improving the wireless throughput and capacity of the cell.

b) 16T/8T horizontal multi-beam antenna.

In ordinary urban areas, 5G antennas should use 16T multi-beam antennas. In rural suburbs, 5G can use ordinary antennas with 8T as the main antenna.

As mentioned above, wide-area coverage does not require digital scanning of the beam in the vertical direction. Conventional beam electrical downtilt adjustment can meet the network coverage requirements. However, in order to give full play to the role of MIMO antennas, multi-beam antennas can be made in the horizontal direction. On the basis of meeting wide-area coverage and continuous coverage, a certain capacity can also be taken into account. Multi-beam antennas also use multiple antenna arrays to split horizontal wide-beam antennas into multiple narrow-beam antennas to achieve spatial diversity. Compared with 3D shaped antennas, the horizontal multi-beam antenna has a relatively simple algorithm and a reduced number of array elements, thereby reducing the size and cost of the antenna.