Radio Frequency Identification Technology
A recent paradigm of communication which popularly known as Internet of Things (IoT), where all the objects of different kinds of our daily life spanning from smart phones, sensors or devices are associated with network enabled objects (like RFID) can communicate with each other and makes a part of Internet. The main aim of IoT is to make Internet more and more inspiring and pervasive. By connecting wide variety of heterogeneous devices and making easy access of the devices, several applications are being used in IoT, which deals with the large number of data generated by the attached devices and make some decisions which is very important for the industry or control the attached devices based on the generated data. There is a huge use of IoT in several domains like medical aids, home automation, industrial automation, mobile health care, electricity transmission and distribution etc. Now a day smart city is one of the emerging domains of IoT, where researchers are proposing several communication models and standards and provide some applications which facilitate the residing citizens by enhancing their everyday standard of life.
With the advancement of communication technology and microcontroller technology, Wireless Sensor Network (WSN) plays an important role in IoT. Sensor nodes, which are very tiny low-cost devices, can sense different parameters in the environment, it can store data in its memory temporarily and can communicate with other electronics devices by using communication technology like IEEE802.15.4 or Bluetooth Low Energy (BLE). On the other hand RFID tag is also a useful device in IoT, which is used to identify an object attached with a RFID tag.
Principles of RFID
The basic principle of RFID technology: the RF signal to be transmitted by the reader&writer is coded and loaded onto the high frequency carrier signal, and then sent out through the antenna. The electronic label entering the working area of reader & writer receives the signal. The relevant circuits of the chip in the card perform voltage doubling rectifying, modulating, decoding, deciphering, and then judging the command request, password, authority, etc. Finally, signal processed by tag according to the command.
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Figure 1
Components of an RFID system:
According to the availability of power, RFID is divided into Passive and Active.
1.Passive Tag: The Passive sensor itself does not have a power supply. Its power supply is generated by a sensor that activated by emitting frequency from Reader, where the data is finally transmitted back to. The Passive Tag is thin and short and has a long service life but the sensing distance is relative short.
2.Active Tag: the price is relatively high; volume is larger than Passive tag because of built-in battery. It has longer service life and longer sensing distance.
According to the frequency, RFID can be divided into three types: LF, HF, UF:
1.Low Frequency RFID (100~500KHz): low frequency RFID has shorter inductive distance; the reading speed is slower. low frequency RFID of 125KHz is commonly used, whose penetration ability is good.
2.High Frequency RFID (10~15MHz): high frequency RFID has longer sensing distance; the reading speed is relatively high. High frequency RFID of 13.56MHz is the mainly used.
3.Ultra High Frequency RFID (850~950MHz~2.45GHz) Ultra-High Frequency RFID has the longest sensing distance and fastest reading speed, but penetration ability is bad.
3.1.1 RFID tags, RFID middleware, Issue, Reader
According to the function, RFID system can be divided into Edge system and Software system. Edge system mainly completes information perception and belongs to hardware component. Software system completes information processing and application. The communication facility is responsible for the information transmission of the entire RFID system.
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Figure 2
1.Electronic Tag
Electronic Tag also known as the transponder or Smart Label, is a miniature wireless transceiver consisting mainly of built-in antennas and chips.
2.Reader&Writer
Reader & Writer is a device that captures and processes RFID tag data, either as an individual or embedded in other systems. Reader&Writer is also one of the important components of RFID system, and its name comes from it can write date to RFID. The hardware of the reader is usually composed of transceiver, microprocessor, memory, external sensor / actuator, alarm input / output interface, communication interface and power supply.
RFID Issues:
- Technological maturity is not enough: RFID technology is new and is not very mature in technology. Due to the reverse reflective nature of UHF RFID tags, it is difficult to apply in metal, liquid and other commodities.
- High cost: RFID electronic tags are relatively expensive compared to ordinary bar code labels, which are costing dozens of times than ordinary bar code labels. If the usage is large, the cost will be too high, which greatly reduces the enthusiasm of the market for using RFID technology.
- Technical standards are not uniform: RFID technology has not yet formed a unified standard. Multiple standards coexist in the market resulting in incompatible of different enterprise products. The main manufacturers of RFID systems provide dedicated systems, which lead to different applications and industries adopting frequency and protocol standards of different manufacturers. Incompatible standards have caused confusion in the application of RFID technology, restricting the entire growth of RFID.
Let us understand how communication is done between them. Different Mobile stations (MS) are attached to a transmitter/receiver which communicates via a shared channel by other nodes. In this type of communication, it makes it difficult for the MAC design rather than the wireline networks.
The very important issues which are observed are: Half Duplex operation, Time-varying channel, and Burst channel errors.
These are explained as following below.
Half-duplex transmission means when the sender and receiver both are capable of sharing data but one at a time. In wireless transmission, it is difficult to receive data when the transmitter is sending the data because during transmission a large amount or a large fraction of signal energy is leaked while broadcasting. The magnitude of the transferred signal and received signal differs a lot. Due to which collision detection is even not possible by the sender as the intensity of the transferred signal is large than the received one. Hence this causes the problem of collision and the prime focus should be to minimize the collision
2. Time-varying channel:
Time-varying channels include the three mechanisms for radio signal propagations they are Reflection, Diffraction, and Scattering.
Reflection –
This occurs when a propagating wave carrying information intrudes on an object that has very large dimensions than the wavelength of the wave.
Diffraction –
This occurs when the radio path between the transmitter and the receiver is collided by the surface with sharp edges. This is a phenomenon which causes the diffraction of the wave from the targeted position.
Scattering –
This occurs when the medium through from the wave is traveling consists of some objects which have dimensions smaller than the wavelength of the wave.
While transmitting the signal by the node these are time shifted and this is called multipath propagation. While when this node signals intensity is dropped below a threshold value, then this is termed as fade. As a result, Handshaking strategy is widely used so as a healthy communication can be set up.
Burst channel errors are called as a contiguous sequence of symbols, which are received in a communication channel, in which the first and last symbols has an error and there is no evidence of contiguous sub-sequence of corrected received symbols. When time-varying channels are used then signals strengths are introduced due to which errors are observed in transmission. For these channels in wireline networks, the Bit rate is high as 10 -3.
Sensor deployment & Node discovery
Internet of Things (IoT) is an emerging technological paradigm where the things can be connected from different fields through the Internet. The rapid advancement in communication technologies, actuators and low-cost sensing devices leads to extensive deployment of IoT devices. Such devices can be deployed in any public spaces provide detailed information about the behaviour of individuals such as personalization, behavior change and personal health monitoring. IoT technology which is being deployed is specially designed to make it invisible, such that the technology does not manifest its presence to the users it is monitoring. For the IoT based healthcare applications, the Wireless Body Area Network (WBAN) is gaining much popularity as wearable devices spring into the marketplace. Multiple sensor nodes can be deployed on different locations of the human body to measure the heartbeat, body temperature distribution, and detect falls. In addition to medical signals, the sensor nodes can be placed to track environmental conditions around the human body as well. Hence, wearable sensor systems afford valuable information about the impact of human health. These systems are not only limited for personal use, can be fitted on animal, car, etc. to construct a wireless sensor network. According to previous estimation, healthcare IoT solutions lay down the platform for extremely accessible, personalized and on-time services that will attain $1 trillion by 2025 hopefully. Wearable systems have emerged as a prominent area in healthcare for managing cardiovascular, neurological diseases etc. These sensors are used on the body surface or inside the human body non-invasively, however it is distinct from invasive implantable devices. This system will be particularly helpful for sensing information inside the human body as the sensors are designed and supported by flexible technologies. The sensing device collects data which is transmitted through wireless communication protocols to a server that is responsible to gather the datasets available for further analysis. WBAN comprised of heterogeneous nodes fixed in and around the human body which is connected to the network. It is characterized by IEEE 802.15 communication standard; generating huge volume of data and gathering it play a vital role in electronic healthcare. Data residing in multiple wireless devices need to be collected and analyzed effectively. Within WBAN datasets may be fragmented across many nodes and if practitioner’s node does not have the correct information then the quality of healthcare processing would be degraded. This chapter presents the overview of wearable sensors for tracking physiological and physical changes in daily life, their basics and applications. Wearable sensor-based systems have enormous potentials to be completely explored and it is anticipated that advancement in technologies will afford the transformation how healthcare will be in future. It highlights the significance of localization in on-body area network and it gives an overview about evaluating the performance of localization systems. It also presents the several types of sensors and methodologies to fuse the data generated by sensors. Since we foreseen a future where the existence of miniature devices communicating through packet radio in both indoor and outdoor environments.
Securing communication.
The Internet of Things (IoT) paves the way to interact with the smart objects namely sensors, hardware, circuits and software. Research in IoT ensures that collecting, processing and distributing the data needs to be improved to carryout data aggregation, processing and dissemination tasks of IoT data management. Data Processing focuses on the characteristics Velocity, Volume, Variety, Variability, and Veracity. IoT Data Management may further be categorized as Communication, Storage and Processing. Data communication involves data processing among objects, sensor data and hardware. To store the data, Cloud or distributed storage is used and processing involves filtering and analytics. Data dissemination distributes the processed data to end users. Message-delay in multi-hop massive IoT network is significantly optimized. This chapter enumerates the IoT data management frameworks, challenges and issues. Also, deployment of IoT Data management for smart home and smart city is described.
The increasing interest of using the Internet of Things (IoT) for the real time applications related to smart remote and automatic monitoring of tasks leads to several research challenges as well. Since from last decade, number of methodologies presented for the IoT enabled wireless communications based on end user applications such as smart traffic monitoring, irrigation management, health monitoring, disaster and security monitoring, weather monitoring etc. Apart from the traffic monitoring, most of the other IoT enabled applications are based on Wireless Sensor Networks (WSNs). The well-known and widely studied research problem of WSNs is limited processing capabilities and battery life of sensor nodes. For IoT enabled WSNs, the key tasks is to aggregate the on-field data periodically and disseminate it to the remote station in order to take the decision through the actuators connected to WSNs. The period process consumes more sensor energy; therefore, it needs the energy efficient data aggregation and dissemination algorithm. In this paper, we proposed the novel Efficient Data aggregation an dissemination using Optimized Tree based clustering (EDOT) for IoT enabled WSNs. The novelty of EDOT approach is that it forms the clusters based on tree construction only when there is data collected by on-field sensor nodes. The EDOT consists of three phases such as tree formation from sink to source sensors in network, after tree formation the clusters formed, finally the data aggregation and dissemination phase. In this paper, we presented the model of EDOT by considering three phases and its performance evaluations as compared to state-of-art methods. The simulation result proves that EDOT improved the efficiency over the existing methods.
Key Takeaways
- Data aggregation is any process in which information is gathered and expressed in a summary form for purposes such as statistical analysis. A common aggregation purpose is to get more information about particular groups based on specific variables such as age, profession, or income.
- Data dissemination is the distribution or transmitting of statistical, or other, data to end users. There are many ways organisations can release data to the public, i.e. electronic format, CD-ROM and paper publications such as PDF files based on aggregated data. The most popular dissemination method today is the ‘non-proprietary’ open systems using internet protocols. “They are used in data dissemination through various communication infrastructures across any set of interconnected networks.” Data is made available in common open formats.
References
- Bernd Scholz-Reiter, Florian Michahelles, “Architecting the Internet of Things”, ISBN 978- 3842-19156-5, Springer.
- Olivier Hersent, David Boswarthick, Omar Elloumi, “The Internet of Things” Key Applications and Protocols, ISBN 978-1-119-99435-0, Wiley Publications.
