Comparing Internet of Things (IoT)-Based Asset Tracking Technologies: RFID vs. BLE

Natalie Hogan | 04 May 2018

Searching for the right asset tracking solution can be daunting. Within the materials handling and supply chain industry, Radio-Frequency Identifier (RFID) is commonly championed as the defacto successor to previous approaches like barcode scanning, but there are other methods that have competitive advantages and technological trade-offs. RFID is one type of technology within the realm of the Internet of Things (IoT). The IoT is a network of devices with sensors and actuators that collect and send data through the Internet. Here we focus on comparing three forms of IoT technology: Passive RFID, Active RFID, and Bluetooth Low-Energy (BLE).

We will begin with the most popular asset tracking technology: Passive RFID.

Passive RFID

• Definition: Technology without an internal power source that uses radio waves created by an RFID reader to send its signal. Passive RFID is the most common form of RFID in warehousing.
• Pro: Low-cost (~$0.10 per tag), small in size and weight, and offers a lifetime use up to 20 years.
• Con: Expensive RFID signal readers are required (~$10k-$20k per portal), there is a short-read range (tags must be within a few feet of the reader), no sensors enabled, and no memory storage.

To track assets through Passive RFID--as seen in many warehouses today--battery-free tags must be placed on the trackable asset and passed within a few feet of a high-power reader. Passive RFID is a great choice if users are looking for technology that has a long battery life and small footprint. These tags can be as thin as a piece of paper. Additionally, the unit cost of Passive RFID tags can make deploying large quantities of tags affordable. The sizable expense associated with this technology comes from the high-powered readers that are needed, costing upward of $10,000 per reader. For this reason, Passive RFID is normally limited to tracking large volumes of assets through a checkpoint such as gateway reader in an inbound dock. If users are looking to track asset movement continuously throughout a warehouse the reader expense can quickly drive up the cost of Passive RFID.

Active RFID

• Definition: Technology that uses battery power to continuously emit a tag’s unique identifier to a given reader. Active RFID is not as common in warehousing as Passive RFID.
• Pro: Long read range (up to 300 feet) and lower power readers are needed ($500 - $2,000). Active RFID tags can have sensors and data storage as well.
• Con: More expensive per tag (~$20), 3-5 year battery life, larger in size and weight.

Active RFID tags operate by emitting information using its own source of power, and can thus interact with inexpensive power-efficient readers. Arguably the largest advantage of Active RFID over Passive is the much longer communication range between the tags and readers. The additional range eliminates the need for Active RFID tags to go through fixed checkpoints as is required with Passive RFID. Additionally, with Active RFID tags, most are sensor-enabled and collect data from the asset. Due to the form factor and technology stack of Active RFID readers, they are not easily integrated with commodity forms of technology or connected to cloud-based systems for big data analytics. While data can be collected, it may be difficult to interpret.

IoT’s Bluetooth Low Energy (BLE)

• Definition: Technology that uses battery powered tags to continuously emit their unique identifier to readers. This is the newest technology within the warehousing space.
• Pro: Emits a long-read range, and requires inexpensive power efficient readers (~ $25 each). BLE can have multiple sensors and data storage, and can easily be linked to Internet-based systems to derive powerful, actionable insights.
• Con: More expensive per tag (~$20), somewhat limited battery life (up to 5 years), larger in size and weight.

There are several similarities between BLE and Active RFID technology. Both operate by emitting their information through battery power to interact with inexpensive power-efficient readers. Both can be sensor-enabled to collect asset data. BLE readers are however more accessible and scalable than Active RFID readers. A strong advantage of BLE over RFID is its ability to interact with other forms of technology: BLE’s can easily communicate with day-to-day devices such as smartphones, laptops, and tablets. The sensor-gathered data can be passed between Bluetooth-enabled devices and uploaded to cloud-based systems resulting in a full-scale IoT ecosystem. This ecosystem can be used to derive insights from the movement of assets over time, to suggest predictive maintenance, and to intelligently prescribe improvements to everything from warehouse layouts to supply chain strategies.