SensThys RFID Solution Promises to Eliminate Failed Reads

By Claire Swedberg

The company's EPIC system includes an encoding method for EPC UHF tags to ensure tag IDs can be read and errors flagged, along with correction algorithms in a SensThys reader, or add-on software for existing readers, to capture tag reads in difficult environments.

SensThys has released an RFID tag data integrity architecture known as EPIC, which the company says is aimed at increasing the accuracy and reliability of EPC UHF RFID tag reads. Unlike existing RFID solutions, the firm reports, EPIC fixes multiple-bit issues in real time as chips are being read. To date, several companies have employed the technology, including pharmaceutical solutions provider  Health Care Logistics (HCL), to ensure all RFID tags attached to their assets or products are read without fail and are identified accurately.

In the event that a tag is compromised, its information can be either corrected or flagged for a user. EPIC relies on several technologies, including additional tag ID data, as well as finite field math—more commonly known as forward error correction (FEC)—to offer an add-on solution to existing RFID systems. Although it is not required for basic EPIC capability, SensThys is also releasing a new reader to enable RFID technology users to provision their system with EPIC's improved read reliability, without other technology adds-ons.

SensThys's Jo Major

Some versions of the system, known as EPIC Level 2, will operate on other UHF RFID readers. Level 4 enhances that functionality with transmission correction using SensThys readers only. Coming soon, the Level 6 version will add additional transmission correction capabilities. EPIC has been under development for years, says Jo Major, SensThys's CEO, and was rolled out to several of the company's existing customers in late 2019 and early 2020. The solution stemmed from customer requests, he says, as several businesses had approached SensThys seeking a solution to address failed or erroneous tag reads.

After years of limited deployment with those and other companies, SensThys is now commercializing the EPIC system to existing and future customers. EPIC is a complete air-management system, Major explains, and is designed to be robust. The solution employs standard UHF RFID tags and an encoding method that offers additional identification data with the EPC number, and it provides algorithms used either directly in readers or on a server to identify potential corruption problems in tag responses to interrogation.

"Originally, we were driven to solve the problem of ghost tags," explains Neil Mitchell, SenThys's sales and marketing VP. In fact, the cause of inaccurate or missing tag reads can be multifold, including damage to a chip or transmission problems caused by the environment. A crack in a chip, for example, could cause one or more digits to flip, thereby providing an erroneous tag ID when the tag is interrogated. A harsh environment could prevent tags from being read, while memory leaks on the tag could pose challenges to read reliability.

According to Mitchell, companies have found that weakly written tags, such as if a chip went through the write zone too quickly or with the write power too low, could result in multiple-bit problems. While read failures may not be common, he notes, even a single tag read failure in many environments could disrupt an entire system. "RFID is an automated system," he states. "If, suddenly, you are taking away the best advantage of RFID by forcing people to do manual intervention to stop errors from getting through, that's a huge issue."

For instance, if tags are being read on reusable plastic containers in the cold supply chain, a tag-read failure could disrupt shipping processes. Tag corruption can result in a tag being missed, and operations must then stop as operators conduct a manual effort to locate the failing tag. Although such errors occur less than five percent of the time, Major says, workers having to locate rogue tags results in efficiency problems. With the EPIC system, standard EPC UHF tags can be encoded either by SensThys or via a user's standard encoder or converter.

A user first sends SensThys a file of EPC numbers it needs encoded on the tags. The company then either provides its customer with encoded EPIC information or sends it to a converter. The reader can then decode the tags as it reads them. While a standard RFID tag is encoded with a 96-bit ID number, the EPIC tag would store 128 bits of information. The system complies with standard encoding formats, including GS1's, Major says, while optionally adding a layer of data concealment that restricts access to only authorized participants. For open systems, if users choose not to supply some parties with the decoding key, the tag will be read by other RFID readers with only the existing EPC number, without the memory protection architecture. "We provide customers with flexibility there," he states.

HCL's Kurt Wolf

As the tags pass through a fixed RFID reader portal or are interrogated by a handheld reader, the EPIC system, running on the handheld or on a server, ensures each tag read is accurate. If one or more digits have flipped, the system can still identify the tag IDs without those digits, as well as alert the user that there may be a potential error. In addition, with forward error correction, a technique in the EPIC algorithm controls errors in the transmission over unreliable or noisy environments by transmitting in a redundant way. With FEC, Major explains "A whole class of failure mechanisms are eliminated. You turn something that's certain death into a minor maintenance thing."

HCL, one of the system's early users, reports that EPIC ensures its customers can accurately identify every product after receiving it. The firm specializes in manufacturing, packaging and distributing products for compounding and dispensing companies used by pharmacies, according to Kurt Wolf, HCL's VP of technology. For three years, he says, the company has provided an RFID-enabled system known as Stat-Stock to help its pharmacy customers manage goods as they are received, stored and dispensed. A tag is applied to each product container, which users then read for inventory-management purposes and to prevent expirations.

However, the RFID read environment for drugs and medications can prove to be challenging. Often, there are more than 100 individual tags in a defined tray, which may be applied to glass vials, saline bags or foil-wrapped products. This means RFID tags occasionally either cannot be read, Wolf says—because the entire tag ID might be missed when interrogated—or the system could experience a flipped digit. Even a single such error can provide critical problems.

Until recently, Wolf explains, "These were pain points we had to deal with." Interference from metallic or liquid items within the read zone can cause a tag to be missed. "With EPIC," he states, "we have a higher guarantee that no error is being made." HCL continues to leverage its traditional EPC UHF RFID tags, which SensThys now encodes to include the EPIC functionality. The company has switched to SensThys readers that automatically run on EPIC, Wolf notes. "Data accuracy and integrity is what the whole gain is for us."

All of the company's customers are now transitioning to the EPIC solution. HCL provides pharmacies with rolls of EPIC-encoded tags, which the pharmacies then apply to products, reading the tags as each item is stored or consumed. "As far as we're concerned," Wolf says, "it's simple to implement." Since the system was taken live about eight months ago, he reports, fewer customers have been calling to complain that they could not find specific tagged products. "I see us continuing to do what we're doing now. We feel that being the first player in this space for error-correction technology gives us a leg up."

The system typically costs an encoding fee of around 10 percent more than existing tags, Major says, though that rate is volume-dependent. For customers reading the tags, there is no charge. "We wanted to make sure customers can use this without worrying about cost restrictions for reading the tags," he states. The solution also includes evaluation kits: a single fixed reader kit with fourth-generation sensArray readers, as well as 500 EPIC-encoded tags. In addition, the company offers its DLL library, as well as a software-development kit and application programming interfaces.