The greater the functionality of the tag the higher the frequency required to communicate the contents of it, hence the spectrum of frequencies shown in Figure 3, Comparison of RFID Frequencies.
Figure 3: Comparison of RFID Frequencies
Sources: (Cheung, Chu, Du, 2009) (Wang, Wang, 2009)
The greater the frequency of a given set of tags the greater the flexibility and the more data they are often capable of storing, capturing as they move through supply chains, and reporting back via readers. The DoD pioneered the use of very high frequency-based RFID tags on pallet containers as they were sent to the Persian Gulf for the Iraq war and for delivery to Afghanistan. Studies indicate that the ability to use the shipping container as a consumer good manufacturer would use a pallet and mix products in it to reflect the needs at the end of the supply chain yield significant ROI over time. Mixed pallet mode shipping is the term Wal-Mart uses to explain this concept, and for the U.S. Army where a ship full of containers can make the difference between a mission being accomplished or not, it is critical for RFID technologies that can scale to support maximum data capture and transmission be used (Kumar, 2007). With the specifics of the technologies defined, the applications of RFID from a distribution, logistics and supply chain standpoint are next discussed.
The breadth of RFID uses or applications continues to broaden as the underlying system components, from databases to scanner and tags, mature rapidly. The most common use of RFID from a process standpoint is for streamlining supply chains. The U.S. Army's reliance in a highly integrated and coordinated supply chain can be seen in the build-out Collaborative Supply Chain Management (CSCM) within this branch of the armed forces (Carroll, Neu, 2009).
RFID has the potential to make several key contributions throughout the DoD supply chains overall and the U.S. Army's specifically. From the monitoring of inbound supplies and their quality levels to the development of Bills of Materials (BOM) definitions for the manufacturing of customized vehicles, armament, supply containers and support systems, RFID has the potential to revolutionize speed of deployment while dropping operating systems significantly. Figure 4, DoD Supply Chain Analysis provides an assessment of each significant process area where RFID can make a significant cost or time-based efficiency reduction based on greater visibility into these shared process areas (Angeles, 2009). Supply chains often don't achieve their highest levels of efficiency when there is a lack of interprocess, intersystem and inter-role visibility. RFID technologies alleviate the lack of visibility by capturing data in real-time an d then reporting it through the use of data management systems that report back analytics of key process areas (AMR Research, 2004) .
Figure 4: DoD RFID Supply Chain Analysis
Sources: (Cheung, Chu, Du, 2009) (AMR Research, 2004) (Hartman, 2005)
(U.S. DoD, 2005) (Wang, Wang, 2009)
Figure 4 shows how RFID can be integrated into the workflow of any distribution-centric organization that is a supplier or manufacturer affiliated with the DoD and the U.S. Army. This example is lifecycle centric as it shows how RFID can speed up the value chain of the U.S. Army as it procures assets and then gets them to the personnel in the field (shown as customers in this graphic). The initial use of RFID on pallets, cases and items drastically reduces the distribution centers and depots' costs and time to manage their inventories. There is also a reduction in incorrect orders for supplies picked for the centers and shipped. The point was made earlier about mixed pallet shipments being a catalyst of higher ROI for RFID implementations. Mixed pallets make it possible for the DoD and the U.S. Army to selectively ship only what is needed through the transportation, theater and Transportation Depot Centers (TDCs). Mixed pallet mode shipping made possible using RFID tags alleviate the need to "burst" or segregate out shipments. Instead the TDCs can drop-ship mixed pallets that are consistent with in-field requirements within hours instead of breaking them apart, (Hozak, Collier, 2008) inventorying product and then re-filling orders. RFID then acts as a source of timely and accurate data throughout the U.S. Army's supply chain to reduce errors and increase efficiencies over time. This value-chain based approach to explaining how RFID can augment and enhance the U.S. Army Supply chain resembles how this technology is used for streamlining the global WalMart supply network as well.
For the last four decades logistics, supply chain, transportation management and warehouse management systems relied on bar coding technologies to track and inventory their products over time (Hozak, Collier, 2008). Bar coding technologies as a result grew rapidly in terms of their breadth of use, application and levels of functionality, yet were constrained due to the amount of data they could provide. Bar coding eventually became pervasive due to its very low cost per tag, low price of scanning and data capture systems, and the ubiquity of the standard throughout many industries.
Despite the cost advantages and its ubiquitous use however the lack of in-channel intelligence, insight into traceability of which specific production lot a given product came from limited the use of bar coding in more demanding, higher velocity industry environments (Carroll, Neu, 2009). Bar coding simply could not scale to meet the requirements of supply chains that were exponentially growing in complexity and depth as a result of Internet-based integration and the availability of real-time data across entire supply networks. Cleary a new technology was needed to address the shortcomings of bar coding for logistics. RFID was specifically designed to overcome the limitations of bar coding as a result.
By definition RFID is an integrated system that provides for real-time traceability and tracking, scanning via radio frequencies and analysis of shipping data all collected electronically (Cheung, Chu, Du, 2009). Scan rates of containers moving through a warehouse using RFID can be transported at up to 35 miles per hour, while for bar cording this comparable task for a pallet of goods is around 6 miles per hour. These exceptionally high levels of scanning speeds are possible due to the fact that RFID does not require line-of-site to read tags as bar coding does (Matalka, Visich, Li, 2009). In addition bar coding labels are often ripped or partially blocked when in a warehouse or moving through a supply chain, making the effort of scanning them even more challenging. For the U.S. Army whose operations are often held in rugged conditions bar coding was only marginally effective as direct, dust, grease, or oil would lesson the readability of a bar code over time.
It was specifically for these shortcomings in private industry that RFID was invested in as a next generation technology for logistics, supply chains, distribution channels. An RFID Transporter or tag, depending on its features and power source, can be scanned for hundreds of feet away. For the U.S. Army and the transporting of hundreds of millions of pounds of equipment rapidly to support missions, this would save significant time and cost, and also ensure greater accuracy of deployments. In comparable terms to Wal-Mart, the ability to deliver the right product, at the right price, to the right customer is key. Table 2, Comparing Bar Coding and RFID Technologies provides a comparison by functional area of each technology.
Table 2: Comparing Bar Coding and RFID Technologies
Optical-line of sight required
Wireless -- line of sight not necessary (there are some exceptions to this however)
Bar coding can read a single label scan
RFID can read multiple tags
Labels tend to be damaged in harsh processes. Etching directly onto a part has increased durability.
Tags are more durable than bar code labels, can be used during and after most harsh environments.
Amount of Information
A 1D bar cord can store 20 alphanumeric characters, while a 2D bar code can store roughly 2K characters.
RFID tags are capable of storing several thousand characters, or several kilobytes, of information
Flexibility of Information
To update information, a bar code label must be replaced with a new bar code label.
To update information, many RFID tags can have their memories updated via wireless communication
2D bar codes provide encryption capability.
RFID tags have manufacturer-installed ID codes that cannot be changed, counterfeiting difficult.
Cost per label or tag
Car code labels typically cost less than $0.01.
RFID tags cost from $0.25 - $0.50, up to $250.
Bar coding is standardized & accepted
RFID lacks complete standardization, especially globally.
State of infrastructure (average levels of readiness)
The infrastructure required in many organizations to support bar codes is easily put into place, updating manual processes using those optically-based reading technologies.
The infrastructure to support RFID tagging is minimal; the data collection stations and data mining software require investment.
Sources: (Cheung, Chu, Du, 2009) (AMR Research, 2004) (Hartman, 2005)