The success of RFID in supply chain management is leading many to consider more personal and pervasive deployments of this technology. Unlike industrial settings, however, deployments that involve humans raise new and critical problems related to privacy, security, uncertainty, and a more diverse and evolving set of applications.
RFID's potential to facilitate everyday life by seamlessly integrating the virtual and physical worlds is still a fairly untapped use of the technology. An RFID infrastructure must be deployed to establish such an environment. Several properties distinguish RFID infrastructures for pervasive computing from those for supply-chain applications:
- Pervasive RFID applications are likely to evolve and grow over time. We already see RFID in elder care and object finding applications, each of which requires a flexible infrastructure that facilitates provisioning. Supply chain applications are typically less dynamic and apply the technology in a narrower capacity (mostly for inventory tracking).
- Because a pervasive application will typically track people and belongings rather than items in inventory, privacy issues must be considered much more carefully.
- People are less predictable than goods moving through established distribution patterns in a supply-chain. As such, we must develop fundamentally new ways to deal with the variable-rate, partial, and noisy data likely to be generated by human activity.
The deployment of a pervasive RFID-based infrastructure in an everyday environment holds the promise of enabling new classes of applications that go beyond tracking and monitoring. Such an operation could, for example, support logging and analysis of individual tag movements over time, allowing a user to ask questions such as ”how often do I get interrupted in my office on an average day?”. Current and historical data on groups of tags could also be used to identify and analyze aggregate phenomena such as the impact of seminars on improving communication between researchers.
A pervasive RFID-based infrastructure must manage three types of information. First, it must manage streams of tag read events (TREs) generated by antennas as they detect tags in their vicinity. Each TRE contains a tag ID, the ID of the antenna that detected the tag (for example reader ID and antenna number), and a timestamp.
Second, the infrastructure must store tag metadata (TMD) which includes tag ID, the name of the tagged object, the name of that object’s owner, privacy parameters, and possibly other information.
Finally, the system must manage reader metadata (RMD), that is the location of each reader and its antennas. The RFID Ecosystem is designed to support the collection, storage, transport, and sharing of TREs, TMD, and RMD across a set of applications in a reliable, scalable, secure, and privacy-oriented fashion.
Important points to consider when deploying an RFID-based infrastructure in a public environment:
1. Consider the relative positions of tags and antennas.
The probability with which a tag is read depends greatly on
- How the tag is mounted on an object, ideally tags should be mounted such that normal use of the object results in the proper orientation of the tag relative to the antenna
- The orientation of the antenna itself, which may help ensure a large number of tags will be perpendicular to it
- The object’s material properties
2. Exploit redundancy
To ensure high TRE's (tag read events) it is important to deploy multiple antennas - the total number depending on the size of the project. Two options for this technique include deploying antennas in more locations and mounting multiple antennas at different angles covering the same area, preferably the region around a doorway or a hallway intersection.
3. Remember health regulations
An important constraint for any RFID deployment is that FCC regulation limits the amount of power a person may absorb from an antenna. This translates into a 9-inch distance between an antenna and any occupied space (such as hallways and offices).
4. Aesthetic Considerations
There may be issues with antennas and RFID readers compromising the aesthetic appeal of a space. To mitigate this, the equipment can be mounted to the ceiling so it is out of sight.
5. System Failures
As with any distributed system, the RFID Ecosystem faces the risk of node and network failures due to system updates, network maintenance, software bugs, etc. To reduce interruptions system updates should be performed during times in which the public space is not in use, such as at night.
6. Privacy Challenges
Pervasive RFID-based deployments raise privacy concerns because they can enable the tracking of people and personal objects by parties that would otherwise be unable or unauthorized to do so. One way of dealing with these concerns is to anonymize data in projects that do not require individual based data. Another solution may be to which TREs should be allowed and which should be denied
In the future RFID will help us answer questions such as: What lab bench was I standing by when I prepared these tissue samples? How should our search-and-rescue team move to quickly locate all the avalanche victims? Did the new school library program increase readership? This increase in data will help us make better choices, work more quickly, and evaluate programs with a higher understanding of what makes an initiative successful or not.