Research on the Automatic routing technology in the Logistics system and IOT

Abstract: With the rapid development of logistics enterprises, tradition logistics sorting has been unable to meet the needs of the development of express logistics. Combining with the RFID technology, the paper proposes a new way of logistics sorting and data routing. By increasing the RFID tag and the AWB in the express waybill will improve efficiency. Using Cluster head selection principle and clustering algorithm of LEACH (adaptive clustering hierarchy). Comparison with original system, verified the practicability of RFID technology and data routing algorithm in the sorting system and easy to use.

Keywords: Wireless sensor network; routing protocol; low energy adaptive clustering hierarchy; cluster head; RFID

0 Introductions

The rapid development of computer network technology, microelectronic technology and radio communication technology enable the implementation of wireless sensor with low cost, low power consumption, small size and short distance possible. The emerging network of communication network is based on the technology development. Specifically, it is through the installation information sensing equipment, such as RFID devices, infrared sensors, GPS and laser scanner, all items are connected to the network together. Facilitate the identification and management.

Express products have complex types, sizes, different packaging. If we use bar code technology in general, it is difficult to ensure that the product transfer process accurately track management, the use of a radio frequency identification system for intelligent storage management, which can effectively solve warehouse management information associated with the product flow, monitor product information, real-time to understand the product, the automatic identification products, locate products. Because the radio frequency identification technology has non-contact, non-line of sight data transmission characteristics, so the product can not be considered directional transmission problems parcels. In addition, due to the characteristics of the electronic tag can record all the data delivery products, more conducive to improving the accuracy of product sorting.

In addition, the logistics center are the most prominent feature is the rapidity and accuracy of the rapid sorting, improve the efficiency of warehousing and distribution, greatly shorten the delivery time, so that products can be promptly delivered to the hands of customers, reduce the distribution error rate. One of the most key technologies is large parcel data needs to be routed to the total server, server software to calculate the area classification each package, which relates to the key technologies: automatic data routing technology.

1 The system structure of Wireless Sensor Networks

Wireless sensor network consists of sensor nodes, sink node and task management node. The sensor nodes are randomly deployed in large numbers within or near the monitoring area, the self-organized wireless network. All sensors to all kinds of information real-time monitoring, sensing, collecting and processing in the monitoring area, such as temperature, humidity, pressure and the chemical concentration, and through multi hop way monitoring data will be transmitted to the sink node, the data is transmitted to the task manager node by satellite and Internet network. The network architecture is shown in figure 1.

1.1 Information access and transmission principle

RFID Logistics sorting system shown is in Fig.2. The system consists of RFID literacy component, communication and display control interface, sorting systems management software. Following describes the composition and main functions of each part.

(l) RFID reader assembly

RFID read by the system of the reader antenna and the RF tag, is responsible for the tray to complete the automatic identification tag, and the tag information read by the interface RS232 transmitted to the computer terminal, as a sorting system management software data sources.

(2) Communications and Display Control Interface

By the CAN communication module and display module. Primarily responsible for the sorting operation information is transmitted to the various tobacco goods sorting station through CAN, the display needs to sort out the information on smoke LCD at the appropriate station, providing instructions for the operation of the sorting personnel.

(3) Sorting System Management Software

The software is mainly responsible for the control and management of the entire sorting system, the completion of the exchange of information management software and RFID reader and updated in real time so that data in a database based on the reader's operations, tracking tobacco goods sorting process.

1.2 The layout of logistics sorting system

Express logistics products according to the content and the weight of the cargo carrier, divided into documents, parcels and cargo. File to import the border without customs clearance, no commercial value of information goods, weighing in at 500 grams; package is required for customs clearance, and the commercial value is higher than the paper goods, weighing in at 30 kilograms; cargo refers to large cargo in 30 kg 250 kg in weight. Three kinds of products have different forms, the traditional bar code cannot scan to accurate information, need to use sorting in different ways.

So the RFID can well solve the problem of sorting, automatic sorting system unified. In addition, because the express products require rapid sorting and delivery to customers, so do not need to construct the storage warehouse specialist, only need to set up temporary storage system.

The specific design scheme is as shown in figure 3.

2 Analysis of Leach algorithms and its performance

Leach algorithm is adaptive cluster topologies, which select cluster head node by circulation and random selection, the whole network energy load average assigned to each sensor node, which can reduce the network energy consumption, improve the survival the entire network time. The Leach protocol model is as shown in figure 4.

In the Leach protocol, compared with the common member nodes, cluster head node has great load and fast energy consumption. As the energy consumption of each node in the network, the balance of the cluster head nodes to avoid premature death, using TDMA (time division multiplexing) way to periodically elect (Round) cluster head. Each round of execution can be divided into two stages, namely initial stage cluster data communication stage and stable. The initialization phase cluster mainly the election of cluster head node, other nodes decide to join the cluster. Enter the data communication phase immediately after establishing stable clusters, duration data communication stage than cluster initialization time establishment stage.

Selection of each cluster head node on the basis of the total number of cluster head nodes needed in the network and each node has become head node to decide by number of cluster. Select the specific measures are: first, each sensor node generates a random number between 0-1, if this number is less than the threshold T (n), then the node will become a cluster head node to the. The threshold T (n) is calculated as follows:

Type, P as a percentage of the cluster head nodes for all sensor nodes in the election, R, G for this round of cycle has not yet become a cluster head node set.

Cluster head node is selected, told the whole network through radio, other nodes in the network according to the received signal strength information decision dependent clusters, establish and inform the cluster head nodes corresponding to complete cluster. Finally, the cluster head nodes using TDMA approach to cluster in each node is assigned to the data transmission time slice.

3 Improved LEACH algorithms

The basic idea of the improved LEACH algorithm is: in between each cluster head nodes allows multi hop forwarding data, thereby reducing the cluster head node from the sink node far energy consumption. The cluster node is still according to the traditional LEACH algorithm, to communicate only with the cluster head node in this cluster. The improved LEACH algorithm, the communication process of cluster head node and sink node is as shown in figure 5.

Each cluster head before transferring data, according to the received signal strength, select effective communication distance neighbor cluster head node as the next hop node. Select the next hop forwarding nodes need to save the overall energy consumption as the basic principles. When the sink node in the effective communication distance within the cluster head, cluster head nodes don’t need to choose the forwarding nodes, can communicate directly with the sink node.

Fig. 6 shows relationship between death node and time. As you can see, the improved algorithm of curve is almost a straight line parallel to the horizontal axis. Because the improved algorithm makes the energy consumption of the network is uniformly allocated to each node, the first node and the last node death is very close to the time, load balance degree of network nodes is improved.

The relationship between the distance of the network lifetime and node is as shown in figure 7. The improved algorithm between cluster head nodes uses multi hop transmission of data to the sink node. Therefore increase the distance between the sink node and the monitoring area is not big "influence on network lifetime can be seen from the simulation results. With the increase of the sink node distance, Network lifetime decay slower, when the sink node position from (50175) to (50390) when the. Network life from the 425 round cut into the 240 round. Reducing the amplitude of nearly 44%, which is superior to the traditional LEACH algorithm.

4 Conclusions

The article analyze and design express logistics distribution center based on RFID and LEACH algorithm, and analyzes the specific process in the distribution of products, compared with the traditional bar code technology can better adapt to express many kinds of products, demand Business Hours short, distribution characteristics of precision, wide radiation area, greatly shorten the sorting time, improves the sorting efficiency, and the sorting process "visualization". This greatly improves the work efficiency and service quality of the distribution center, save a lot of manpower cost, reduce the loss of goods flow rate and the occurrence of the possibility of human error, improve more quickly, accurately express logistics service to customers.

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