What is RFID – Alternative for Logistics?

Knowing where every item is at all times – and better still, knowing its status – is just one prerequisite for an effective logistics process. Various wireless technologies enable goods to be tracked for this purpose; be that within one warehouse or in supply chains that span the globe. In this process, the language often falls on RFID. But what is RFID and what are the alternatives?

What is RFID?

Automatic, contactless identification of objects is made possible thanks to RFID (Radio-Frequency Identification). To do so, the respective object is provided with an RFID tag or transponder. The data saved on the transponder (such as the article number) is transmitted to the reader wirelessly as soon as the transponder is within range. Depending on the design in question, the transmission distances range from a few millimetres to around 10 metres, which is more usual. Active transponders draw their power from batteries, while passive variants are supplied with power through the wireless signals from the reader. Slower RFID systems with a maximum range of just one metre operate in a frequency band of between 120 and 150 kHz, while faster UHF transponders with a range of up to 10 metres operate in a band around 868 MHz. High-speed microwave RFID systems with a range of up to 200 m operate in a frequency band of between 3.1 and 10 GHz.

The right product, in the right quality and right quantity, in the right place at the right time, with the right costs – this is the well-worn “6R rule” of logistics, which snappily outlines just how the goal of an effectively functioning supply chain needs to be.

Wireless and IoT technologies are increasingly being used for logistics purposes to monitor these goals and remain informed at all times as to where which goods are and what their status is.

Using such technologies ensures a considerably clearer overview of the status of the goods and the supply chain as a whole. If required, companies can then use this to track the location and status of the goods (e.g. temperature, air humidity and damage) in real time.

Through a networked supply chain of this kind, the processing and response times can be shortened, stock levels reduced, and just-in-time production processes improved. According to the DHL trend report “Internet of Things in Logistics”, the use of networked IoT technology can generate an extra EUR 1.77 billion for the global logistics industry by 2025.

“The supply-chain industry finds itself at a turning point. Due to new hardware technologies and information and analytical solutions, traditional systematics are being questioned like never before. Technology offers considerable opportunities to reduce costs and increase profitability,” explains José F. Nava, Chief Development Officer, DHL Supply Chain.

These days, asset tracking – i.e. the tracking and localisation of an object within a warehouse or somewhere along the supply chain – is already a commonplace application. Almost all available wireless technologies are used in the process.

Stock-taking in the blink of an eye with RFID

RFID technology is a classic when it comes to logistics applications – after all, the technology is almost 20 years old now.

It has proved its worth in a vast range of industrial applications over the years and is commonly found today in intralogistics solutions, i.e. logistics solutions within one single supply centre or warehouse.

Compared to classic identification systems such as barcodes or laser marking, transponder data can even be written and read with RFID when there isn’t actually any visual contact. Data can also be expanded, modified or replaced, which opens up entirely new applications.

In the same vein, researchers at the Massachusetts Institute of Technology have developed a system in which small drones that don’t pose a hazard to warehouse personnel are used as a relay between RFID tags and an RFID reader.

In turn, this allows the RFID reading range to be expanded considerably.
In this case, the flying robots are not only able to read RFID tags from dozens of metres away, but also use triangulation to simultaneously determine the locations of the tags and associated products to an accuracy of around 19 centimetres.

Even in a large warehouse, a method such as this means that stock can effectively be taken in the blink of an eye.

Transmitting additional status parameters

Current RFID developments can even supply more than just the basic identification and location information: combining RFID transponders with sensors enables a multitude of other parameters in the delivery process to be recorded, too.

RFID sensor transponders, such as those developed by the Fraunhofer Institute for Photonic Microsystems (IPMS), integrate antenna, identification and sensor technology into one single chip.

“Our passive RFID sensor transponders measure physical parameters such as humidity, vibration or temperature before transmitting these wirelessly to a reader, which also provides the power,” explains Dr Andreas Weder, Team Leader at the Fraunhofer IPMS.

“They are compact, lightweight, maintenance-free and do not require their own power supply, which enables them to be easily integrated into a variety of loading aids.”

Consequently, sensor transponders from the Fraunhofer IPMS not only assist in the previously established identification and shipment tracking of goods at a certain point in time, but also provide information on what has happened to raw materials, semi-finished goods and end products during their progression along the supply chain.

Global asset tracking

Asset-tracking systems are increasingly being connected to the cloud to enable goods to be monitored along global supply chains as well. What’s more, the tracking information can be saved to the cloud and analysed in a more straightforward manner, which provides new insights into the various processes.

However, combining short-range technologies such as RFID, Bluetooth or Wi-Fi with the cloud makes things tricky when the tracked object is on the move and making its way from Europe to the USA, for example.

Relatively low-cost wireless modems with a long range are therefore an upcoming solution for mobile asset tracking. Technologies like LTE-M and narrow-band (NB) IoT use 4G mobile-communication networks that can easily accommodate IoT traffic: both of these are efficient enough to ensure that the life of the battery lasts several years.

These new technologies facilitate global asset tracking at a price that enables practically any package to be tracked anywhere in the world.

Less cargo at sea

A worldwide tracking system such as this is of particular interest for container logistics, too.

In the case of an international shipment, the number of interactions can quickly rise to 200, conducted by more than 25 agents – such as freight forwarders, port logistics, customs, shipping lines, receiving agents and many more. It stands to reason, then, that freight forwarders are so keen to keep a close eye on their containers all the way along the supply chain; seamlessly and with real-time updates.

After all, a lack of transparency reduces the agility of the supply chain and the level of service delivered to the end customers. To name one example, tyre manufacturer Michelin collaborated in the development of a real-time asset-tracking system for shipping containers based on the technology and global network of Sigfox.

This system is already in use for several of Michelin’s critical, intercontinental supply chains. It enables shipments to be continuously tracked all over the world due to the trackers’ ability to automatically detect local radio-frequency standards and adapt themselves accordingly.

“Our experiences from the pilot phase and further investigations have convinced us that – among other things – we can reduce the level of stock at sea by 10 per cent and increase the accuracy of estimated arrival times by 40 per cent thanks to real-time management,” says Pascal Zammit, Senior Vice President Global Supply Chain at Michelin.

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