Maximising mobility

We have finally arrived at the commoditisation of both RFID readers and tags. The introduction of sub-US$1000 readers this year has halved prices from just 12 months ago, while US$0.15 passive tags in large quantities are not uncommon. This lowering of entry costs means a wider variety of applications, many of which were not feasible at the higher cost base. These are now benefiting from RFID at the lower price points.

With this cost reduction is an accompanying shift in the way organisations approach RFID. The 'slap-and-ship' nature of applications, where a tag is applied to the box or pallet as it leaves the dock for shipping out, is being superseded by the desire to utilise the RFID network more fully, collating the network data to control and optimise a range of internal processes to achieve competitive advantage.

The flow-on effect of this has been an increase in the complexity of RFID environments. Complexity itself is not uncommon; in fact, it is rare for companies to deploy RFID entirely in isolation. A typical application environment may include any combination of RFID readers and printers, barcode scanning systems, programmable logic controllers (PLCs), proximity sensors, light stacks and LED message boards.

Integrating any or all of these peripherals in a real-world environment poses significant challenges, in particular the minimisation of electromagnetic interference (EMI). The growing adoption of handheld readers is further multiplying EMI issues to the point where an additional middleware management layer is now required.

Coping with dense environments

Interference in congested environments is partially addressed in the electronic product code (EPC) 'Gen 2' protocol with its dense-reader mode, which enables multiple readers to work in close proximity without interfering with each device's read and write speeds and/or overall performance. It is often combined with additional EPC concepts such as listen-before-talk, which ensures that a channel is not being used before communicating over that channel.

But dense-reader mode is also limited by the fact that it addresses interference at an individual reader level rather than at a macro or whole-of-environment level. It works by minimising interference within the air protocol, ensuring compliant devices are more cooperative with other spectrum users. There is growing evidence that an additional multi-protocol, multi-device middleware management layer is required to act as a whole-of-network 'traffic cop', assigning device on/off and operating frequencies to further minimise the potential for interference.

This is particularly important in an environment where handheld readers are involved. A spectrum analyser is often used to map both physical and infrastructure-related assets that may be causes of interference. Conducting a spectrum analysis in an environment with handheld readers is much more complex due to mobile device locations and the transient nature of the signals.

At a base level, the devices should be set up as a group of readers in a dense-reader mode with listen-before-talk also enabled. However, organisations should then establish a middleware coordination layer to manage the devices and direct RF traffic over the network. This 'master reader' capability, as found in Sybase RFID Anywhere, not only enables individual readers to be synchronised for improved operation in dense-reader mode, but typically also uses a variety of additional technologies to further minimise interference across the network as a whole.

One of these technologies is time slicing, which enables the RFID middleware to partition the on/off time available for each reader in the environment, for example, on a rolling 100 ms basis. Another technology involves integration with general-purpose input/output (GPIO), enabling peripherals that assist and control the timing of the on/off switching to plug directly into the reader environment.

Consider for a moment a simple warehouse environment with eight dock doors and multiple readers at each door location. If all readers are continuously 'on' and a box or pallet arrives at door four, the read and transmission of data to the central system at door four may interfere with tag reads from doors three and five, something that would not be a problem if the readers at doors three and five were not continuously set to 'on'. Integrating a proximity sensor into the environment is one simple solution, such that when a package or pallet moves within range of the sensor it automatically activates the closest reader for a defined period of time to ensure the data can be collected and transmitted back to the central warehouse management (WMS), inventory control (ICS) or enterprise resource planning (ERP) system for tracking and analysis. Combined with time slicing, this is an effective way to have readers in dense environments work together.

Expanding the middleware layer

Middleware is software that resides between the RFID network of devices and back-end enterprise systems. It abstracts the proprietary hardware interfaces and filters, aggregates and adds value to the raw data received from the readers and other devices and sends it to the central enterprise system using standard interfaces, languages and protocols, although increasingly sophisticated middleware systems are emerging that can be installed near readers at the 'edge' of the network to process data without requiring a connection to the central enterprise server.

Importantly, middleware also provides management and security over the RFID network itself. With network management capabilities being embedded into the RFID standards and implemented, in many cases, using middleware, there is increasing emphasis being placed on maximising the benefits of an existing RFID implementation either by expanding its use to other parts of the organisation or by forming a tighter integration with enterprise information systems for data collation and analysis.

One of the key drivers for this is the superseding of the 'slap-and-ship' approach so commonly associated with supply chain RFID implementations and, particularly, retail SCM mandates like Wal-Mart and Tesco. Certainly, there is anecdotal evidence in the United States to suggest that supply chain companies are taking a longer-term view to RFID implementations. Suppliers no longer just want to meet retail mandates, they also want to utilise the data from the physical RFID network for their own competitive advantage.

A key realisation for many supply chain companies, particularly those with mandated systems, is that there does not need to be one-to-one mapping between the physical RFID network and a single application. It is possible, and in most cases beneficial, to have many applications feeding off the one physical network since the main overhead, infrastructure investment, has been taken care of. Likewise, the middleware platform can also manage multiple functions, including interference, and integration with other peripherals in the environment.

An example of this could be a cold chain supplier of perishable goods. Having borne the costs to comply with a retail mandate and set up RFID, the network could be expanded to a temperature-sensing application. Aside from controlling the RFID network and managing interference in the refrigeration facilities, the middleware framework could be further utilised, for example, to interface with a programmable logic controller (PLC) to monitor refrigeration units to ensure compliance with food safety regulations and minimise energy consumption.

Similarly, the reuse of the combined physical network and middleware layer can be applied to control the flow of a conveyor belt in a process automation environment. For example, when the proximity sensor on the production line is triggered by the arrival of the product, the network management solution launches the printer applicator to apply an RFID tag to the product and to read it.

If the read is successful, the control arm on the conveyer belt moves the product to a packing pallet. If the read fails, it triggers a retag before the product is moved on for shipment. The middleware platform not only minimises interference in this process using its status as master reader, but also enables the supply chain organisation to better manage and collect data across the entire process.

Managing the mobile evolution of RFID

As handheld devices become increasingly common in RFID-enabled environments, middleware will play a critical role in determining the readiness of an organisation to manage the network requirements and complexities involved. Such complexities will almost certainly include varying standards, protocols, hardware and physical requirements, such as the deployment and management of infrastructure at non-traditional locations.

Aside from realising synchronisation capabilities in dense-reader mode to contain the potential for interference, establishing a single middleware interface to manage mobile devices will become a key factor for future-proofing supply chain systems.

Take a prototype RFID implementation with five RFID readers. At this size, it is likely that each device is configured for use individually through the interface provided by the reader manufacturer. However, if the environment scales to 50 devices (both mobile and fixed), when configuration changes are required, such as changing the power output levels on all of the 50 plus antennas, individual configuration and deployment is no longer practical. Configuration is just one aspect of network management. The ability to monitor the network to ensure peak performance and provisioning software to the various network nodes is also required.

This concept is not restricted to mobile terminals. Any RFID reader, or any piece of hardware for that matter, should be managed through the middleware layer. Mobility is not the driver for this; rather, it's the same as the need for desktop management software in a large organisation. It's just too much work to configure and monitor each desktop individually.

Given the rapid development of RFID and the potential for changing needs over the product life cycle, it is critical for supply chain companies to ensure their middleware device management platform can scale appropriately, for example, to deploy configuration changes across the warehouse, or to manage new reader and tag types in a multi-protocol, multi-device environment.

The 'always-on, occasionally connected' nature of handheld devices, such as readers, will also prove a key driver. Although most devices are Wi-Fi enabled, it cannot be assumed that they will always be connected to the network. As a result, increasing emphasis will be placed on on-device agents which provide the intelligence to enable the device to execute the appropriate logic while it is offline, and then relay the collected information to the central warehouse management systems when it is reconnected into the RFID network. Such an approach also recognises the importance of multi-device support in an end-to-end warehouse management approach.

The forecast complexity of future RFID deployments and associated implementation issues, including interference and integration, underline the importance RFID network management will play in the ongoing adoption of the technology. A flexible, extensible and scalable middleware platform will become increasingly critical to ensuring success and competitive advantage in implementing RFID solutions.

Martyn Mallick is director of RFID and mobile solutions at Sybase iAnywhere and Mark Geddes is director of Sybase Mobility Solutions for Australia and New Zealand.