5G technology has the characteristics of high speed, low delay and high battery life. With the rapid development of 5G, it will be combined with new logistics equipment technology, big data, blockchain, intelligent manufacturing, etc., and actively applied to intelligent manufacturing and a wider range of fields.

     With the rapid development of modern industry and the increasingly fierce market competition, the three-dimensional warehouse technology has put forward higher requirements. The tunnel stacker and AGV are the core single machines of the whole automatic solid warehouse system, and their stability directly determines the operation efficiency of the solid warehouse. The communication of these traditional devices adopts WiFi technology. Due to the defects of WIFI technology itself, there are a series of problems such as vulnerable to interference and easy to drop lines, especially the blocking of WIFI signal by the dense goods in the overhead warehouse, which can not make the equipment run stably. And with the diversified and intelligent application of logistics technology, such as the need to add vision, information reading and other functions, the requirements for communication bandwidth and communication quality are higher. Therefore, a new high stability, strong anti-jamming ability, the application of a wide range of communication demand is particularly urgent.

      1、Advantages of 5G networks

     5G communication emerges as The Times demand, low delay, large bandwidth, large capacity, and the unique technical advantages of wireless cellular network, such as high reliability, high security, wide coverage, etc., will digitize and wireless transformation of human-machine-material, point-line-field in factory workshop and logistics park. In order to make use of big data, IoT, AR, AI and other emerging technologies, on the basis of information and automation, to create digital, intelligent solutions. Improve the efficiency of analysis, decision and execution of logistics system, integrate logistics resources, integrate processes and processes, and ensure the production pace. At the same time, 5G wireless communication mode to achieve flat factory network, further enable flexible manufacturing. 

       2、5G technology application scenarios

Category 1: Industry EMBB. Communication capability based on 5G large bandwidth.
Category 2: Industry Upstream Video. Based on video and image job.
Category 3: wireless industrial control. Real-time control based on 5G low delay.
Category 4:5G sensing technology. Sense and location capabilities based on 5G communication technology.

       3、Application of 5G in core logistics equipment

       1.AGV cluster scheduling

       AGV is the most automatic and intelligent equipment in the logistics industry at present, and it is also the fastest developing technology. The visible direction is the autonomous mobile robot AMR. On the e-commerce sorting platform, hundreds of AGVs are running at the same time, as shown in Figure 1. The amount of data transmitted by AGV real-time control is not large, but the frequency of data transmission is high and the time delay is demanding.
E-commerce vendors sort out AGVs in operation

        2.AGV cooperative control

       Industrial manufacturing and handling objects vary in size, weighing hundreds of tons, making it impossible to design an AGV for every size. It is necessary for multiple AGVs to cooperate with each other to carry a very large and overweight object, which not only reduces the customization cost of AGV, but also can be flexibly combined and reused to save investment. The assembly of large equipment, such as aircraft wings, also requires multiple AGVs to lift synchronously, and the accuracy of the objects' parking position is also affected by synchronous start and stop. When large equipment moves to turn, different AGVs in formation need to execute different motion parameters.

       In the case of multi-AGV cooperative handling of overweight objects, in consideration of safety and inertia, multiple AGVs need to synchronously start and stop, otherwise a single AGV will independently exceed the load, that is, the command arrival time difference caused by communication delay is very harsh. Communication delay should be controlled within 5 ~ 10 microseconds in order to leave more time for electromechanical servo system. Clock synchronization between AGVs is also required at 1 microsecond.

       3.Cloud Control of AGVs

       5G's large uplinks bandwidth and low latency make AGV's cloud-based visual navigation possible. Uuploading AGV local camera data and computing processing on the cloud can eliminate a lot of hardware and software costs of deploying lidar, IPC \GPU and purchasing algorithm license locally in each AGV.

       Visual navigation generally requires that visual frames must be refreshed and uploaded at least once every 100ms cycle as well as sending position information to prevent collision. The delay between uploading and Posting should be controlled within 20ms. In order to leave plenty of time for cloud image processing and location calculation.

       4.C2C control of stacker

       Stacker is the core equipment of automatic three-dimensional warehouse. The communication methods are generally wired communication, infrared communication and WIFI。

       Wired communication requires very high cable and wiring, and the failure rate is high, and the application is very inconvenient.

       Infrared communication must be installed in a straight line. In the harsh environment, such as dust, poor illumination and other conditions, the distance and reliability of data transmission are poor, and data transmission interruption is easy to occur.

       Due to the defects of WIFI technology itself, there are a series of problems such as interference, capacity, offline and so on, especially the blocking of WIFI signal by the dense goods in the overhead warehouse, which can not make the stacker run stably. In the operation of electrical equipment data acquisition and equipment maintenance required by the big data communication capacity of low bandwidth can not bear. 5G wireless communication will completely eliminate these problems。

       The stacker adds machine vision, mainly with industrial cameras. In the inbound and outbound links, the appearance of the packing box damage detection; In the loading link of the overhead warehouse, the posture of the container is detected; In the process of inventory and sampling inspection, online real-time inventory can be realized through cloud video, which is safe and efficient.

       Vision requires big data uploading. If 5G network is adopted, uncompressed photos can be uploaded to the edge server within 2 seconds. Combined with the image processing time, it can meet the pace of 3 to 4 seconds to complete a product appearance inspection. At present, the major visual stacker manufacturers have started the technology update of the built-in 5G communication module.

       4、Requirements for 5G network construction

       Different from MBB business, equipment communication in logistics scenario has the following typical characteristics
Table 2 Typical characteristics of equipment communication in logistics scenario

       1).Ultra-depth coverage: viaduct scene, narrow roadway, dense cargo, high demand on signal penetration strength; 

       2).Long distance no handover: logistics equipment in large workshop operation, need no handover within 300 meters;

       3).The design of the switching belt is complex: the design of the switching belt varies greatly under different workshop patterns and process requirements.

       4).Large amount of concurrent communication: in extreme cases, a logistics equipment with a workshop of ten thousand square meters can communicate approximately ten thousand times/second.

       5、Suggestions on selection of 5G terminals

       According to the GSA report, as of October 2019, 172 5G terminals have been released globally, and 38 have been commercially available. A total of 15 CPEs will be released or commercially available by November 2019. Since 2003, Huawei has invested heavily in the research and development of communication modules, and has nearly 20 years of rich experience so far, enabling high-speed wireless network connections in all walks of life. In October 2019, Huawei released the MH5000 5G industrial module, priced at 999 yuan. By 2020, the price of CPE will drop below $300. As of December 2019, there are typically several types of commercially available 5G modules and terminals

      6、Concrete hardware architecture implementation diagram

    In 5G application scenarios, logic controllers of core logistics equipment such as stacker and AGV mostly adopt Befu PLC based on PC terminal, and 5G terminal selects Huawei CPE industry terminal. Both parties provide Ether CAT automation protocol for two PLC standard equipment, which can realize the second-level Ethernet communication. Data exchange between master and slave devices is conducted through 5G base station. For special application scenarios, mobile edge computing (MEC) technology is introduced

       7、Summary

      5G technology will enable the industrial Internet, further integrate IT application with industrialization, and provide new impetus to the industry. 5G technology inserts wings for the development of core equipment in the traditional logistics industry, integrates artificial intelligence achievements and big data wisdom, and improves the informatization degree, operation management efficiency and production tempo of manufacturing logistics, warehouse logistics and off-site logistics.