An existing Active Antenna Unit (AAU) at a terrestrial base station is designed to ensure the coverage quality of the terrestrial network. A vertical beam of AAU deployed at a base station is usually 15 degrees, and a default antenna down-tilt is usually 6 degrees. Current ground 5G base stations cannot provide effective and stable wireless network coverage for networked UAVs and electric vertical take-off and landing vehicles eVTOL. To meet the requirements of intelligent network connections such as video backhaul, low-altitude navigation, and airspace supervision in low-altitude networks, this proposal proposes a method for improving low-altitude airspace coverage performance based on the NCR architecture of low-altitude networks. The NCRbased RIS node is added for low-altitude airspace. The RIS device deployment location, orientation, and RIS real-plane beam are dynamically adjusted, and the beams oriented toward terrestrial base stations and networked UAVs in lowaltitude airspace are coordinated to improve low-altitude airspace coverage performance.

This work focuses on low-altitude networks in the field of wireless communications. To ensure ground coverage performance of the existing ground base station, a certain downtilt angle is set for an antenna, and a back beam of the antenna points to a space domain. According to the current low-altitude network spatial domain test, the low-altitude spatial domain has a large number of radio signals, and the overlapping coverage is high. Under the same Reference Signal Received Power (RSRP), the Signal to Interference plus Noise Ratio (SINR) value that represents the radio signal quality is lower than that on the ground. In addition, a service requirement of a low-altitude network focuses on an uplink high-bandwidth service such as video surveillance and security rescue. However, an existing low-altitude communication network cannot meet a service requirement. This paper proposes a coverage enhancement method for a low-altitude network oriented to a large uplink bandwidth, and aims at the problems of low-altitude spatial domain signal clutter and high uplink background noise, and abandons the existing solution of adding a power amplifier or installing a large gain antenna for improving uplink coverage performance. The omnidirectional antenna carried by the Unmanned Aerial Vehicle (UAV) is replaced with a directional antenna, and the multi-feed lens antenna is used to transmit and receive RF signals in all directions. This increases the uplink antenna gain and improves the uplink coverage performance. In addition, the uplink achieves a higher Modulation and Coding Scheme (MCS). Multi-feed intelligent transmit control can also be used to increase the uplink 2T transmit ratio and finally increase the uplink transmission rate to meet the large uplink bandwidth requirements of video backhaul services.

From the perspective of UAV security, the takeoff control and dispatching of UAVs in low altitudes must strictly follow civil aviation standards. However, some UAVs still do not follow civil aviation standards. Some individuals even secretly lift the no-fly restrictions and manually operate UAVs for flight. It has brought great hidden dangers to national security and the personal safety of the masses. This paper proposes a synesthesia coordinated networked UAV rejection system, which constructs the networked UAV control area, and establishes the airspace scope of the core area, control area, and early warning area. Construct a synesthesia network for the control region of the network-connected UAV system, and develop an integrated synesthesia-coordinated detection module for enhanced situational awareness and operational efficiency. Relying on the synesthesia network ground base station sky platform, the UAV rejection module is built, the synesthesia network and the UAV rejection module are linked to detect the UAV, and the black-flying UAV is rejected and counteracted.

5G network involves a network-controlled repeater and RF repeater defined in 3GPP R17 is transparent to the base station and UE. It directly amplifies and forwards received signals. This reduces costs but causes interference. A control module is introduced in the network-controlled NCR defined in 3GPP R18 based on the forwarding module, so that the relay can perform scheduled and directional forwarding under the control of the base station, thereby reducing network interference. Based on the NCR, the NCR-MT module is used to detect the surrounding 5G network, and the detection result is sent to the data analysis module to determine the deployment location of the NCR-MT module. If the preset conditions are met, the NCR-MT starts to start the main device to forward and amplify the source wireless signal. If the preset conditions are not met, the deployment position is changed, so as to achieve the objective of forwarding and amplifying 5G signals.

The NR TDD network adopts large bandwidth and high frequency band networking, and the characteristics of high frequency band will lead to large 5G wireless pathloss. On the uplink, the UE transmit power and the antenna port configuration of the terminal is less than those of the base station. In the process of services, users may encounter service difficulties due to the limited uplink coverage performance. This document describes a coverage and capacity enhancement solution. The coverage enhancement solution is based on MR and MDT data from the n28 band, which indicates the limitation scenarios of the n41 band. The MR and MDT sampling points have been collected in the maintenance platform as well as intra-system and different frequency points and RSRP of the 5G cell in the n28 band. The capacity enhancement solution is based on the overlay scenario of the NR TDD network with strong master control, the uplink time slot is added to the class A cell and the uplink capacity can be improved without interfering with class B cell.

Traditional indoor distribution systems in 2G, 3G, and 4G networks are mostly single-path, but the indoor distribution systems in 5G networks require dual paths to get greater capacity by space division multiplex. This document describes the reconstruction from a traditional single-path indoor distribution system to a dual-path indoor distribution system on a 5G network. Suitable scenarios need to be found in which the engineering workload is small and the cost is low, and in the scenario, a key point is that one path in the dual-path indoor distribution system would be leaked signals from nearby floors. If the level of the leaked signal is too low and the signal quality is poor, only low-order modulation modes can be used. Even if dual-stream access is provided, the download rate cannot be improved. The download rate is even lower than that of a single-path indoor distributed system. The suitable sicario in which leaked signal can support RANK 2 is discussed in the paper that 5G users can get higher throughput in the dual path upgrade indoor distribution system.

During the evolution from LTE to NR, multi-antenna technology is a key technology to improve the overall system throughput. The multi-antenna technology is an effective means to increase system capacity compared with networks extension. The more the antenna arrays are, the narrower the beams become to achieve better isolation and interference control. Based on narrow beams formed by beam-forming, the same spectrum resources are reused in the same geographic area to obtain resource multiplexing gains. Negatively, as the multi-antenna solution, coverage overlapping increases and inter-cell load imbalance occurs accordingly, which is a key problem to be addressed in the network optimization practice.

During the initial stage of 700MHz NR construction, 5G terminals penetration is less, which will cause the problem of low spectrum utilization and efficiency. The NR and LTE may share the common 700MHz band spectrum, which may improve the existing 4G users' experience and the overall system (NR & LTE) efficiency. Dynamic power sharing methodology can be considered for the spectrum sharing process to improve user perception. After 700MHz NR construction and commercialization, it can be considered to couple with the 2.6GHz and 4.9GHz of NR TDD to complement the wide-area coverage, deep indoor coverage, and hotspot capacity of the overall network.