An Active RFID Tag for Outdoor Billboard Management

Transcription

1 2017 2nd International Conference on Communications, Information Management and Network Security (CIMNS 2017) ISBN: An Active RFID Tag for Outdoor Billboard Management Hui JIANG 1,2, Kai ZHOU 1,*, Jian-jun YI 2, Long CHEN 1, Qiang LI 1 and Hong-yue SUN 1 1 School of Mechanical Engineering, University of Shanghai for Science and Technology, 516 Jungong Rd., Shanghai, China 2 School of Mechanical and Power Engineering, East China University of Science and Technology, 130 Meilong Rd., Shanghai, China *Corresponding author Keywords: RFID, Billboard Management, Active tag, Low power strategy. Abstract. Billboard is installed in the business district or beside the highway. It is a kind of advertising facility. To manage the outdoor billboard efficiently, a novel active RFID tag is proposed. The hardware of the RFID tag is introduced. In order to reduce the energy consumption of the hardware, this research highlights a low power strategy. To support multiple readers to work simultaneously, a communication protocol is designed. The staff can get the billboard ID stored in the RFID tag with the portable reader, the detailed information of the billboard can be acquired with the billboard ID. The testing result shows that the RFID tag works well for the application of billboard Introduction Billboard is a kind of advertisement facility. It is installed in the business district or along the highway. At present, billboard management is achieved manually by recording its key information and location, the information will then be compared with the corresponding data stored in the database. The amount of billboards is so large, and the legal billboard and the illegal billboard are usually mixed. It is difficult to manage the billboard in the hot spot area. To solve the problem, a novel active RFID tag is proposed in this paper for outdoor billboard The active RFID tag is mounted in the billboard, and the staff can inspect the billboard with a portable reader. The billboard ID (stored in the RFID tag) can be obtained by the reader. The information (recorded in the database) related to the billboard can be retrieved by the ID through the network. Then, the staff can compare the information and the billboard to decide whether the billboard is legal or not. As a result, the application of the proposed RFID tag can largely improve the efficiency of billboard Implementation of RFID Tag and Reader Implementation of Hardware The hardware can be divided into two types according to portability, which is shown in Figure 1. A stationary reader consists of a computer, a reader and tags. The communication of the reader and the computer is realized with the USB port. The other type is the portable reader which is used by the staff to inspect the billboard. Readers and tags communicate at the frequency of 2.4 GHz on the basis of IEEE protocol. The hardware is composed two parts: reader and tag. The chip CC2530 developed by Texas Instruments was adopted to develop them. The chip has a 2.4GHz RF transceiver which was designed according to protocol IEEE However, the transmission power is no more than 4.5 dbm. In order to extend efficient range and improve reading capacity in the complex environment, the chip CC2591 was used as the power amplifier, which makes the transmission power up to 20 dbm. As 427

2 shown in Figure 2, a tag mainly consists of two chips (CC2530 and CC2591), two batteries and an antenna. On the same time, the reader contains two chips and an antenna. Figure 1. The communication among tags, readers and host devices. Design of Communication Protocol Figure 2. The active RFID tag. The standard ISO/IEC is widely used in the active RFID. The slot ALOHA algorithm employed in the standard solves the collision problem of reading multiple tags [1,2]. Nilsson et al. (2007) demonstrated that RFID with IEEE has a higher throughput than the RFID tag with ALOHA algorithm [3]. Similarly, Moeinfar et al. (2012) designed an active RFID tag with IEEE [4]. However, low power strategy and the problem of reading efficiency have not been further discussed. Implementation of the Low Power Strategy Based on IEEE Nilsson et al. (2007) studied the beacon enabled IEEE protocol [3]. The chip CC2430 was used and the work duration was set to the shortest one. If a 3V/180mAh CR2032 battery is used as a power supplier, it can only last for 18 days. If a 2500mAh battery is used, it can make the tag working for 250 days. However, a billboard is updated in 2 years in Shanghai, so the battery life of the tag must be longer than that. When beacon is enabled, work duration and sleep duration are decided by macbeaconorder (BO) and macsuperframeorder (SO). However, the value range of BO and SO are defined by protocol IEEE , so it is hard to reduce power consumption in the beacon enabled mode [5]. Fortunately, IEEE provides a beacon disabled mode, which makes it possible to design a low power consumption mode. Figure 3. Low power consumption working mode. To wake up the tag and send ID to the reader in the beacon disabled mode, an IEEE based low power consumption mode is proposed, which is shown in Figure 3. If a reader does not send any commands, the tag will enter a wake-up waiting mode automatically and last for 5ms in each cycle. Each cycle is 1s, which refers the total time of wake-up waiting and the sleeping mode. In order to wake up the tag, the reader sends the wake-up command, the command should last 4ms to ensure that 428

3 the tag can receive wake up command in the waking status. Furthermore, the time a reader sends the wake-up command should be over 1 second. After the tag is waked up, the reader can send reading command to the tag to obtain billboard ID. When ID is received by the reader, it will send an ACK. Then the tag will enter a command-waiting status after it receives the ACK. Otherwise, the ID will be resent by tag. If the tag does not receive the command for 1 min, it will re-enter the sleeping mode. Figure 4. Flowchart of sending data. Design of the Communication Protocol Based on IEEE The RFID tag is mainly used in billboard management, so it should store the billboard ID to distinguish different billboards. On the other hand, IEEE only supports a peer-to-peer and star network [6]. In the practical application, more than two readers may work simultaneously. Therefore, a communication protocol based on IEEE is proposed, as shown in Figure 5. Figure 5. The communication protocol based on IEEE In Figure 5, Seq. represents the sequence of data package, which is used to filter repeated packages. Reader ID is allocated 1 byte, which is used to distinguish different readers. Tag ID is allocated 1 byte to extend the short address. The billboard ID is the combination of the short address and Tag ID, which is 3 bytes in total. Command represents specific operation instructions, and the length is 1 byte. Status indicates reading status. The last byte of tag-to-reader data package is the current battery voltage. 429

4 System Testing The experiment equipment contains one personal computer, a ViewPad 97i Pro tablet computer and a reader. The reader was linked to tablet computer by the USB port. 30 RFID tags were taken to conduct the experiment. The screenshot of the software of billboard information is shown in Figure 6. The information such as billboard ID, battery voltage and signal strength are shown to the staff. The software can get the rough position from the database with the billboard ID, which will make it easier to find the billboard. When the staff chooses a billboard which he or she wants to get detailed information, the software will show all the information and mark it on the map. After the inspection, the staff can save the inspection results in the database with the software. Figure 6. Screenshot of the software of billboard information. The reading latency of the tag is an important factor of the user experience. 30 RFID tags are used to conduct the experiment, and the average reading latency is acquired. RFID tags were installed 50 meters away from the reader. Before obtaining billboard ID, reader sends wake up command to make tags enter working status. We started the test with 1 tag, and then increased 1 tag each time. For each time, 10 tests were executed and the average value were calculated. As shown in Figure 7, the average collection time for 30 tags is ms, which is fast enough for the application of billboard 430

5 Figure 7. Relationship of number of tags and average collection time. The energy consumption of the proposed active RFID tag can be calculated according to the research of [3]. When the tag does not receive any wake-up command, it needs a 1200mAh battery for the 2-year proper working. If a 2500mAh battery is used for the power supply, it can be read for 2800 times in 2 years. Therefore, the proposed RFID tag is perfect for the application of billboard Conclusion This research proposes a novel active RFID for outdoor billboard The hardware of the active RFID tag is introduced in this research. To reduce the energy consumption of the RFID tag, the IEEE based low power strategy is proposed. To support multiple readers to work simultaneously, the IEEE based communication protocol is designed. The active RFID tags are installed in billboards, then each billboard has a unique ID. After the staff gets billboard ID with the portable reader, detailed information of the billboard can be acquired and shown in the software interface. Finally, the testing result shows that the proposed RFID tag works well for the application of billboard The RFID tag has characteristics such as long efficient distance and low average collection time, it can be widely used in areas including container management, car management and dangerous cargo, etc. References [1] W. J. Yoon, S. H. Chung and S. J. Lee, Implementation and performance evaluation of an active RFID system for fast tag collection, Computer Communications. 31 (2008) [2] W. J. Yoon and S. H. Chung, ISS-TCA: An identified slot scan-based tag collection algorithm for performance improvement in active RFID systems, IEEE transactions on industrial electronics. 59 (2012) [3] B. Nilsson, L. Bengtsson, P. A. Wiberg and B. Svensson, Protocols for active rfid-the energy consumption aspect, in: International Symposium on Industrial Embedded Systems, IEEE, 2007, pp [4] D. Moeinfar, H. Shamsi and F. Nafar, Design and implementation of a low-power active RFID for container tracking at 2.4 GHz frequency, Advances in Internet of Things, 2 (12) 13. [5] S. Farahani, ZigBee Wireless Networks and Transceivers, Elsevier, Oxford, UK, 2008, pp [6] N. F. Timmons and W. G. Scanlon, Analysis of the performance of IEEE for medical sensor body area networking, in: First Annual IEEE Communications Society Conference on Sensor and ad hoc communications and networks, IEEE, 2004, pp