Port is an important hub of global shipping, and the efficiency of port operation is closely related to its automation and intelligence. Since China's 5G license was officially issued in 2019, the application of 5G in port container terminals has been gradually carried out. The port has high requirements for safe production, complex physical environment and diverse service requirements. The 5G public network solution cannot meet multi-scenario service needs of the port in terms of capacity, coverage, latency and reliability. In this context, ZTE has proposed an effective design solution for port 5G private network, which has been verified in a number of port projects and can be replicated on a large scale. 

5G Network Needed for Smart Port 
The port operation process is divided into two categories: vertical transport system and horizontal transport system, and involves vertical transport by quayside container crane, container tally, horizontal transport inside the container yards, and vertical transport by gantry container crane. Security and efficiency are basic requirements of port operators. Smart ports include the following scenarios:
—Communication with offshore anchorage: The offshore anchorage is generally more than 20 km away from the shore. Before entering the port, the cargo ship is anchored at the anchorage to handle a series of work, such as declaration, joint inspection, navigation and berthing, which requires phone calls and data backhaul.
—Remote control of quayside container crane and intelligent tally: After the container ship is berthed, several quayside container cranes lift containers from the ship to the container truck. More than 20 cameras and programmable logic controllers (PLC) are installed on one quayside container crane. The driver in the office can remotely control the crane through the multi-angle video and console. When transporting containers, the intelligent tally system automatically identifies the container number, damage and other information, and the tallyman can complete the tally work remotely. The quayside container crane is 50 meters high and has high uplink video traffic. PLC requires low latency and high reliability. 
—Remote control of unmanned container trucks and gantry crane: Unmanned container trucks transport containers between docks and container yards, and send back vehicle status and video data in real time. In special cases, the remote driver takes over the driving and removes obstacles. The containers stacked in the yard seriously block and reflect wireless signals. Logistics turnover causes the stacking height of the container to change from 0 to 20 meters. When the height is low, the inter-cell interference of wireless signals is serious. The remote operation principle of gantry cranes is similar to that of quayside container cranes, but its network requirement is lower than that of quayside container cranes.
—Drone preventive maintenance: The port attaches great importance to safety production and carries out preventive maintenance regularly. Because the port covers a large area and the height of the ship can reach 100 meters, manual preventive maintenance is difficult and inefficient. At 120 meters in the air, the drone can complete a large-scale preventive maintenance rapidly, and discover security risks in time through the received HD video and image recognition.

Building Independent 5G Private Network for Hierarchical Wireless Coverage
There are many kinds of port services, which have high requirements for network capacity, delay, security and reliability. Generally, an independent 5G private network architecture is built, with dedicated 5G base stations, dedicated user plane function (UPF) or miniaturized 5GC moved down to the port campus. This solution ensures that user data is not sent out of the port, realizes accurate wireless network planning, and guarantees service experience. 
The port features diverse wireless coverage scenarios, so it is necessary to design network coverage layer by layer (Fig. 1).

High Availability and Differentiated Scheduling Policies to Guarantee Multi-service Experience
The port operates all day, and any transport shutdown caused by failure will bring great losses, so the design of port 5G private network must consider the high availability scheme. As end-to-end network availability equals to the multiplication of the availability of each node in the network, it is necessary to increase the availability of each node. At the network access side, two CPEs are deployed to establish dual links that support active/standby mode and load sharing mode, so that the availability of terminal equipment can be enhanced. At the same time, 5G and the original optical network of the port form wireless and wired backup links, which increases availability while protecting the existing investment in network construction. At the network system side, single-board and network-level backup solutions can be deployed. It is necessary to provide the backup of power boards, baseband boards, and the main control board, and BBUs and RRUs also need to be backed up to build a dual-band dual-layer wireless network. When the active device fails, the network can be restored quickly through active/standby switching. 
There are many kinds of services at the port, and their requirements for the network vary greatly. Under the default network configuration, there will be competition for network resources among services, resulting in network congestion and a decline in service experience. Different services can be isolated through network slicing, and different radio algorithm parameters can be configured in the slices to implement differential guarantee of the services.
For the control service of remote quayside container crane, physical resource blocks (PRB) can be reserved to provide resource guarantee, user-level pre-scheduling can be configured to reduce latency, and conservative scheduling can be configured to improve transmission reliability. For the video backhaul service, high-target block error rate (BLER) can be configured to increase the weight of QoS scheduling. For the data backhaul service with low real-time requirements, low-priority QoS can be configured, and the resource can be preempted by other high-priority services. 

ZTE's port 5G private network design solution has been deployed and verified in many ports. A range of port services such as remote control of quayside container crane, intelligent tally, unmanned container trucks, drone preventive maintenance, and ultra-long-haul coverage of offshore anchorage have passed the trial verification and pressure tests, and have gradually expanded their application scale. A 5G private network customized for the port will enhance the intelligence of the port and help it operate efficiently.