Introduction

Having location information can be very useful and it has so many applications. It can answer questions such as: Are we almost to the campsite? 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? Can I automatically display this stock devaluation chart on the large screen I am standing next to? Where is the nearest cardiac defibrillation unit?, and so on. Service providers can also use location information to provide some novel location-aware services. The navigation system based on a GPS is an example. A user can tell the system his destination and the system will guide him there. Phone systems in an enterprise can exploit locations of people to provide follow-me services.

Researchers are working to meet these and similar needs by developing systems and technologies that automatically locate people, equipment, and other tangibles. Indeed, many systems over the years have addressed the problem of automatic location sensing. Because each approach solves a slightly different problem or supports different applications, they vary in many parameters, such as the physical phenomena used for location determination, the form factor of the sensing apparatus, power requirements, infrastructure versus portable elements, and resolution in time and space.

For outdoor environments, the most well-known positioning system is the global positioning system (GPS) (Peng and Mirsa, 1999), which uses 24 satellites set up by the U.S. Department of Defense to enable global 3D positioning services.

Introduction

A MAC protocol is used to address resolving potential contention and collision when the communication medium is used. Many MAC protocols have been proposed for wireless networks (e.g., Bharghavan et al., 1994; Fullmer, 1998; Fullmer and Garcia-Luna-Aceves, 1995; Garcia-Luna-Aceves and Tzamaloukas, 1999; Garcias and Garcia-Luna-Aceves, 1996; Lin and Gerla, 1997b; Lu et al., 1999; Vaidya et al., 2000), which often assume a common channel shared by mobile hosts.

Contention-Based MAC

The MAC protocol is essential for stations that share a common broadcast channel. CSMA protocols (Kleinrock and Tobagi, 1975) have been used in a number of packetradio networks in the past (Leiner et al., 1987). These protocols attempt to prevent a station from transmitting simultaneously with other stations within its transmitting range by requiring each station to listen to the channel before transmitting. Unfortunately, the performance of the CSMA protocol suffers from hidden-terminal problems and exposed-terminal problems substantially. To remedy these problems, several approaches (Bambos and Kandukuri, 2000; Bharghavan et al., 1994; Colvin, 1983; Fullmer and Garcia-Luna-Aceves, 1995; Karn, 1990; Monks et al., 2001) were proposed in the literature. Karn (1990) proposed a protocol called MACA that attempts to detect collision at the receiver by establishing a request-response dialog between senders and intended receivers. When a sending station wants to transmit, it sends an RTS to the receiver, which responds with a CTS if it receives the RTS correctly.

Introduction

The (localized) topology-control technique lets each wireless device (locally) adjust its transmission range and select certain neighbors for communication while maintaining a decent global structure to support energy-efficient routing and to improve the overall network performance. A distributed method is localized if it runs in a constant number of rounds (Naor and Stockmeyer, 1993). By enabling each wireless node to shrink its transmission power (which is usually much smaller than its maximum transmission power) enough to cover its farthest selected neighbor or selecting only a portion of nodes to forward data for others, topology-control schemes can not only save energy and prolong network life but can also improve the network throughput through mitigating the MAC-level medium contention. Unlike traditional wired and cellular networks, the movement of wireless devices during communication could change the network topology to some extent. Hence, it is more challenging to design a topology-control algorithm for ad hoc wireless networks: The topology should be locally and self-adaptively maintained at a low communication cost, without affecting the whole network's performance.

Wireless networks have drawn a good deal of attention in recent years because of the potential applications in various areas. Many routing protocols have recently been proposed for wireless ad hoc networks. The simplest routing method is to flood the message, which not only wastes the rare resources of wireless nodes but also diminishes the throughput of the network.

Introduction

In Chapter 4, we basically studied how to assign time slots to links such that the simultaneous transmissions will be interference-free. In Chapter 5, we studied how to assign frequency channels to wireless terminals such that (1) they are interference-free; i.e., the spectrums assigned to nearby terminals will be disjoint; or (2) the links formed by the assigned channels will form a network with certain networking properties such as being connected. In this chapter, we study the channel assignment to wireless networks when the channels are defined by CDMA codes.

Code-division multiple access (CDMA) provides a higher capacity, flexibility, scalability, reliability, and security than conventional frequency-division multiple access (FDMA) and time-division multiple access (TDMA). It has already been widely deployed in 2G cellular communication systems and was proposed for the emerging and future wireless systems, including WLANs and wireless ad hoc networks. In a CDMA system, the communication channels are defined by pseudo-random codewords, which are carefully designed to cancel each other out as far as possible. Each communication utilizes the entire available spectrum, and every bit of data is multiplied by the codeword used by the communication channel. Thus, many duplicates of the same information are transmitted to ensure that at least one gets through. The number of duplicates, which is equal to the length of the codeword, is known as the spreading factor. The inverse of the length of the codeword is known as the rate of the codeword.

As companies seek to control their brands and products across ever-expanding global supply chains, further visibility can be extended beyond the point of sale to the points of use across the product lifecycle. Closed-loop product lifecycle management (closed-loop PLM) focuses on tracking and managing the information of the whole product lifecycle, with possible feedback of information to product lifecycle phases. Implementing the PLM system requires a high level of coordination and integration of the product-embedded information devices (PEIDs) that track the products. To fulfill this need, the concept of closed-loop PLM, its system architecture, modeling framework, and metrics have been addressed.

Introduction: closing the product information loop

From a product lifecycle management perspective, a product's lifecycle can be separated into the following main phases: beginning of life (BOL), including design and production: middle of life (MOL), including use, service, and maintenance: and end of life (EOL), characterized by various scenarios such as reuse of the product with refurbishing, reuse of components with disassembly and refurbishing, material reclamation without disassembly, material reclamation with disassembly, and, finally, disposal with or without incineration.

We may say that between the first two phases, i.e. design and production, the information flow is quite complete and supported by intelligent systems such as CAD/CAM, product data management (PDM), and knowledge management systems that are effectively and efficiently used by the industry. However, the information flow becomes less and less complete from the MOL phase to the final EOL scenario.

The market for radio frequency identification (RFID) technology is growing rapidly, with significant opportunities to add value, but also, because of the challenging issues that are identified in the chapters that follow, many opportunities for failure. This book brings together pioneering RFID academic research principals to analyze engineering issues that have hampered the deployment of RFID and to share “best practices” learnings from their work, building on the tradition of the Auto-ID Labs. The Auto-ID Labs consortium of leading universities around the world includes Auto-ID Labs at Cambridge University, Fudan University, Keio University, the University at St. Gallen and the ETH Zürich, the University at Adelaide and, most recently, the ICU, South Korea. The principal investigators represented here have conceived, obtained funding for, and executed research projects using RFID technology. The authors share their experience in the design, test, prototyping, and piloting of RFID systems, both to help others avoid “reinventing the wheel” and to set the stage for what is next in RFID.

Because RFID technology has evolved from proprietary systems operating at different frequencies in jurisdictions with different RF regulatory restrictions, most RFID work has been divided into communities operating at one frequency or another. In RFID Technology and Applications we bring together principal investigators with experience in passive RFID systems across a range of frequencies including UHF 860–960 MHz (EPC GenII/ISO 18000–6c) and HF 13.56 MHz (ISO 18000-3), but also, breaking with precedent, we include experts in active (with power) RFID systems.

In industries including aerospace, pharmaceuticals, and perishables, as covered in the preceding chapters, counterfeit trade has developed into a severe problem. While established security features such as holograms, micro printings, and chemical markers do not seem to efficiently avert trade in illicit imitation products, RFID technology, with its potential to automate product authentications, may become a powerful tool to enhance brand and product protection. The following contribution aims at structuring the requirement definition for such a system by providing a non-formal attack model, and outlines several principal approaches to RFID-based solutions.

Counterfeit trade and implications for affected enterprises

Intangible assets constitute a considerable share of many companies' equity. They are often the result of extensive investments in research and development, careful brand management, and a consistent pledge to deliver high quality and exclusiveness. However, the growth of markets in Asia, where these intangible assets are difficult to protect, the trend in favor of dismantling border controls to ease the flow of international trade, and the increasing interaction of organizations in disparate locations require new measures to protect these assets and safeguard companies from unfair competition. Especially product counterfeiting, the unauthorized manufacturing of articles that mimic certain characteristics of genuine goods and may thus pass off as products of licit companies, has developed into a threat to consumers and brand owners alike.

Counterfeit trade appears to affect a wide range of industries.

Introduction

In June 2003, Wal-Mart asked its top 100 suppliers to begin using RFID tags on pallets and cases shipped to the Dallas, Texas region by January 2005. This announcement, coupled with initiatives by companies such as Metro, Tesco, and Albertson's, propelled the RFID industry forward. In the period since that announcement, companies have worked feverishly to understand and utilize RFID in their supply chain in order to meet retailers' requirements and, more importantly, create business value for themselves. Initial RFID implementations predominately affected only a small portion of the supply chain (from retailer distribution center to store backroom) and focused on tagging pallets and cases. Given this limited supply chain exposure, determining the payback and, ultimately, creating business value have proven challenging. Early research is, however, providing evidence that, even under the aforementioned restrictive conditions, RFID is yielding a positive return: (1) Gillette found that RFID makes a difference in the tracking and managing of promotions [1]; (2) MIT's work on electronic proof-of-delivery (ePOD) at the retail distribution center revealed a valuable use of RFID [2]; and (3) results from a Wal-Mart-supported University of Arkansas study suggested that RFID can help reduce out-of-stocks [3]. Given the limited scope – i.e. retailer distribution center and store; pallets and cases only – it is very encouraging that solid business cases have already been found. In reality, these preliminary uses of RFID in the supply chain are merely the tip of the proverbial iceberg.

Introduction

The five years from 2000 saw enormous developments in the way in which technologies such as RFID could be deployed in the consumer goods supply chain as illustrated in the preceding chapter (Ch. 9). While many of these developments were generic, it became increasingly clear that other sectors would need to make substantial adjustments were they to capitalize on the significant cost reductions and standards developments that had occurred. It was for this reason that the Auto ID Labs set up the Aerospace ID Programme. The aim of the programme was

The barriers to be examined ranged from issues of technical feasibility, via economic viability hurdles, to questions of operational viability – that is, whether solutions could survive a harsh range of operating conditions. These hurdles to be addressed (see Fig. 10.1) served as a sanity check for setting the research directions which are reported in Section 10.5.

This chapter tells the story of the Aerospace ID Programme, its formation, its operations, and the results.

Background

As mentioned above, the background to the Aero ID Programme was the major development in the use of RFID in the consumer goods industry, led by the Auto ID Center and exemplified by the major initiative from Wal-Mart in 2004.

This book is addressed to business management and project managers as well as researchers who are evaluating the use of radio frequency identification (RFID) for tracking uniquely identified objects. In an effort to make RFID project management less of an art form and more of a science RFID Technology and Applications brings together pioneering RFID academic research principals to analyze engineering issues that have hampered the deployment of RFID and to share “best practices” learnings from their work. By extending the original work of the Auto-ID Center at MIT and the subsequent Auto-ID Labs consortium led by MIT that now comprises seven world-renowned research universities on four continents, this book seeks to establish a baseline for what RFID technology works today and identifies areas requiring research on which other researchers in academic, commercial, and regulatory agencies can build.

The researchers represented in these pages have gathered on three continents in the course of the RFID Academic Convocations, a research collaboration hosted by the Auto-ID Labs that started in January of 2006, at MIT, and was followed by events co-hosted with the Chinese Academy of Sciences and Auto-ID Labs at Fudan University in Shanghai, as RFID Live! 2007 pre-conference events, and by the event in Brussels organized with the European Commission Directorate-General for Informatics (DGIT) and the Auto-ID Labs at Cambridge University. These Convocations bring together academic researchers with industry representatives and regulatory stakeholders to collaborate across disciplines and institutions to identify challenges faced by industry in adopting RFID technology.

From an historical perspective it is the small CMOS integrated circuits (versus inductively coupled transponders) which incorporated microwave Schottky diodes that made it possible to manufacture small passive RFID tags. In this chapter it is demonstrated how recent improvements in CMOS technology (0.18u and later) make it possible to use an inexpensive MOS transistor for the EPC GenII/ISO 18000-6c compliant transponders that operate in the UHF band. The basic variables for designing low-power (high-readability) RFID tags and details of incorporating temperature sensors into semiconductor chip designs at the Auto-ID Labs, Fudan University, Shanghai are described.

This chapter explores chip design principles that affect the performance of RFID tags. The metrics of tag performance will be illustrated and the corresponding optimization technologies will be introduced. Many early implementation issues for RFID tags involved low read rates such that tags did not “wake up” in response to interrogator signals and transmit their IDs, especially with transponders operating at UHF frequencies that are subject to interference from liquids and metals.

Metrics of tag performance

In RFID applications, tag performance will directly influence the success of the whole system. Understanding the metrics of tag performance is important in order to foresee the overall system performance. This section will analyze the metrics of tag performance, including read range, read rate, communication speed, etc.

An act of government, in this case the State of California, is the driving force behind the research topic addressed in this chapter. The use of RFID to establish an ePedigree in the pharmaceutical supply chain brings to a head basic RFID frequency and technology choices that are available from vendors today. This chapter describes how the RFID Center of Excellence at the University of Pittsburgh works with pharmacy distribution and retail as they evaluate different requirements specific to the healthcare life sciences industry.

Different RFID reader environments and the physics of RFID that impact systems performance, including fundamentals of orientation, are characterized in order to explain different findings from pharmaceutical industry HF RFID pilots and from fast-moving consumer goods retail UHF RFID implementations. Alternatives of HF and UHF, namely near-field and far-field RFID options, are explored (the analogy is to compare an RF environment that is like “a prisoner in a cell” with an RF environment like “a bird in the sky”), and performance models are presented and evaluated with respect to constricted orientation and distance in real-world scenarios. A systematic layered approach for analyzing RFID interrogator-to-tag RF protocols is proposed, an insight that, should it be adopted by reader manufacturers, would dramatically improve RFID reader interoperability and testing. Recommendations are made with respect to modeling RFID systems performance and where pilots can help prepare the way for full implementation of RFID systems.

While the origins of RFID lie more than 50 years in the past, passive RFID technology is actually only in its infancy. This might seem an odd statement given that other technologies which have had a comparable history – computers for example – are considered mature. What makes RFID different?

The reason is that RFID, perhaps more than other technologies, is a systems technology that transcends the reader and the tag. Readers and tags are rarely, if ever, used alone. They are components of much larger systems, some of which they augment, and many of which they fundamentally enable. There are many other components to the system in which RFID participates, and, for RFID to really blossom, every component of the system must blossom. So every new advance in, say, battery technology or networking will launch a new wave of creativity and invention in RFID. This will create new applications. These new applications will increase the demand for products, further subsidizing research, and thus laying the seeds for the next invention and the next wave. It is my firm belief that RFID is currently only in its first wave.

EPC technology, developed first by the Auto-ID Center and then by EPCglobal, probably represents the state-of-the-art of the first wave of RFID. Today, EPC tags are being deployed worldwide in thousands of sites and billions of EPC tags have been read. Passive EPC tags are being used for intra- and inter-company applications on a scale perhaps never seen before.

The cold chain is a concept resulting from the field of the transformation and distribution of temperature-sensitive products. It refers to the need to control the temperature in order to prevent the growth of micro-organisms and deterioration of biological products during processing, storage, and distribution. The cold chain includes all segments of the transfer of food from the producer to the consumer. Each stage crossed by a temperature-sensitive product is related to the preceding one and has an impact on the following one. Thus, when a link of this “cold chain” fails, it inevitably results in a loss of quality and revenue, and, in many cases, leads to spoilage.

The cold chain concept can also be applied to many other industries (pharmaceuticals, dangerous goods, electronics, artifacts, etc.) that require the transport of products needing to be kept within a precise temperature range, in particular at temperatures close to 0 °C, or even below [1]. Owing to very strict rules from government agencies the expression “cold chain” has even become one of the key sentences at the heart of current concerns in the pharmaceutical field and in biotechnology [2].

The food industry

Temperature is the characteristic of the post-harvest environment that has the greatest impact on the storage life of perishable food products. In some regions of the globe, especially in tropical and subtropical regions, post-harvest losses of horticultural crops are estimated to be more than 50% of the production due to poor post-harvest handling techniques such as bad temperature management.