22
USE OF SHORT-RANGE Wireless Communications TECHNOLOGY TO ENHANCE ACCESSIBILITY
in Public SPaces
A Group Project Report completed in partial fulfillment of the requirements for
EECE 285 – Group Project
Prepared by
Owen Kirby, Nikolai Matni, Noriel Rilloma,
Randy Sandhu, Navid Soofi and Natalie Silvanovich
Supervisor: Prof. David G. Michelson
This work was supported by NSERC STPGP 257684
and a grant from the Neil Squire Foundation, Burnaby, BC.
4 April 2005
Abstract
Recent developments in short-range wireless communications technology are helping bring the vision of intelligent buildings closer to reality. This will allow architects, developers, and building managers to:
§ Enable sustainable practices that reduce energy and resource consumption
§ Simplify building management and enhance security
§ Create a pleasant environment for building occupants and visitors alike
§ Enhance the productivity of building occupants
§ Improve accessibility for the mobility disabled.
However, an effective in-building wireless deployment strategy in support of intelligent buildings concepts must account for:
§ The many and varied needs of building managers, occupants, and visitors
§ Overlap among the capabilities of the many short-range wireless standards have been released (e.g., Wi-Fi, Bluetooth, ZigBee, RFID) or are in development (e.g., Wi-Media, Wireless USB, IEEE 802.15.4a.)
§ Innovative applications and usage models that were not envisioned by the original developers of these short-range wireless standards
§ Practical issues associated with range and reliability, coexistence, and security.
Table of Contents
Abstract 2
list of figures 5
Chapter One INTRODUCTION 6
Chapter Two SURVEY OF SHORT-RANGE WIRELESS COMMUNICATIONS TECHNOLOGIES 8
2.1 Introduction 8
2.2 Modern Nature of the Standardization Process 9
2.3 Survey of Short-Range Wireless Technologies 12
2.3.1 RFID 12
2.3.2 Wi-Fi 13
2.3.3 Bluetooth 14
2.3.4 ZigBee 14
2.3.5 Wireless USB 15
2.4 Discussion 16
References 19
Bibliography 20
Chapter Three POTENTIAL APPLICATIONS OF SHORT-RANGE WIRELESS COMMUNICATIONS TECHNOLOGY IN PUBLIC SPACES 21
3.1 Introduction 21
3.2 The History of Wireless Technologies in Intelligent Buildings 23
3.3 Present-Day Applications of Short-Range Wireless in Intelligent Buildings 24
3.4 Future Applications of Wireless Technology 26
3.4.1 Localization 27
3.4.2 M2M 27
3.4.3 Security and Safety 28
3.4.4 Energy Conservation 28
3.4.5 Accessibility 29
3.4.6 Accessibility Features for the Mobility Disabled 29
3.5 Discussion 30
References 31
Bibliography 32
Chapter Four DEPLOYMENT 33
4.1 Introduction 33
4.2 Range and Reliability 33
4.2.1 Bluetooth 34
4.2.2 ZigBee 34
4.2.3 RFID 35
4.2.4 Wi-Fi 35
4.2.5 Wireless USB 36
4.3 Coexistence and Interference 36
4.3.1 Wi-Fi and Bluetooth 37
4.3.2 ZigBee 37
4.3.3 Outside Interference 37
4.4 Security 38
4.4.1 Wi-Fi Security 38
4.4.2 Bluetooth Security 40
4.4.3 RFID Security 40
4.5 Physical Deployment 41
4.5.1 Access Point Locations 41
4.5.2 Interference Considerations 42
4.5.3 Throughput Considerations 43
References 43
Bibliography 45
Chapter Five CONCLUSIONS 46
list of figures
Figure 2.1 Summary of Standards and their IEEE Industry Group 11
Figure 2.2 Summary of Short-Range Wireless Capabilities 16
Figure 2.3 In-Building Wireless Range vs. Data Rate Overlap 17
Figure 2.4 Functionality Overlap Between Short-Range Wireless Technologies 18
Figure53.1 Applications of short-range wireless communications technology 22
Figure64.1 Bluetooth Range by Class 34
Figure84.2 Recommended Channel Allocation for 2D Deployment 42
Chapter OneINTRODUCTION
Intelligent buildings that optimize their environments and interact with their occupants have been a topic of study and speculation for decades. In general terms, the concept seeks to integrate previously disparate systems and introduce communications and automation technology in an effort to:
§ Enable sustainable practices that reduce energy and resource consumption
§ Simplify building management and enhance security
§ Create a pleasant environment for building occupants and visitors alike
§ Enhance the productivity of building occupants
§ Improve accessibility for the mobility disabled
In the 1980’s, the advent of the microprocessor led to the first efforts to reduce the intelligent building concept to standard practice. In the 1990’s, the advent of computer networks led to a second wave of interest. Now, recent developments in short-range wireless communications technology are helping to bring this vision ever closer to reality.
In the process of developing plans and strategies for using short-range wireless technologies to help implement intelligent buildings, architects, developers, and IT managers must consider:
§ The capabilities and overlap of the many short-range wireless communications standards that have recently been released (e.g., Wi-Fi, Bluetooth, ZigBee, and RFID) or are in development (e.g., Wi-Media, Wireless USB, IEEE 802.14a, etc.)
§ The many and varied needs of building managers, occupants, and visitors.
§ The potential for developing innovative applications and usage models that were not envisioned by the original developers of these short-range wireless communications standards.
§ Practical issues associated with deploying these technologies, including range and reliability, coexistence, and security.
This report provides architects, developers, and IT managers with the essential background information that they require as they develop of in-building wireless deployment strategies.
In Chapter 2, we review the types of standards-based short-range wireless communications technology that are currently available or in development and their capabilities.
In Chapter 3, we review previous work concerning intelligent buildings, consider how short-range wireless communications technology will enable or alter and identify the types of applications that could be enabled in public spaces using short-range wireless technology.
In Chapter 4, we review the deployment and coexistence issues associated with these technologies.
In Chapter 5, we draw conclusions.
Chapter TwoSURVEY OF SHORT-RANGE WIRELESS COMMUNICATIONS TECHNOLOGIES
2.1 Introduction
The development and growth of short-range wireless communications during the past decade has been phenomenal. Enabled by advances in electronics technology, driven by pent-up consumer demand, and ignited by a flurry of standards development, short-range wireless communications technologies such as Wi-Fi (IEEE 802.11), Bluetooth, ZigBee, Wi-Media and Wireless USB provide a broad range of capabilities that are changing the way in which computing and control applications are implemented. Here, we discuss the development, capabilities and limitations of these technologies.
Today, designers of intelligent buildings are very fortunate to have a wide variety of technologies available. However, to take full advantage of these options, designers require information regarding the way these standards were developed, the technologies that are available, and the extent to which their capabilities overlap.
This chapter is organized as follows:
In Section 2.2, the modern nature of the process by which recent and upcoming short-range wireless protocols are being developed is explained.
In Section 2.3, the intended applications, capabilities and limitations of short-range wireless communications technologies are discussed.
In Section 2.4, the overlap among the capabilities of short-range wireless communications technologies is outlined.
2.2 Modern Nature of the Standardization Process
The need for unified global standards has increased immensely with the growth of computer networks and the need for interoperability among network protocols.
The nature of the short-range wireless standardization process is far different from that of previous years. Wireless standards are no longer being developed by associations representing broadcasters and service providers as was the case for early cellular networks. They are now being developed on a global scale by a partnership between an international standards organization (eg. the IEEE) and a consortium of consumer electronics companies.
Before 1980, major companies each developed proprietary standards, meaning that protocol suites created by one company did not work with a competitor’s. In order to increase the interoperability of protocols and the products that used them, the International Organization for Standardization (ISO) created the Open System Interconnect (OSI) in 1982.
The purpose of the OSI was to create a common framework for standards and increase the interoperability of networks that used different protocols. Protocols were to be created with respect to the OSI Reference Model, a model consisting of seven unique layers:
§ Application
§ Presentation
§ Session
§ Transport
§ Network
§ Data Link
§ Physical
with the physical layer being the lowest and the application layer being the highest.
Previously, organizations such as the Telecommunication Industry Association (TIA) and the Electronics Industry Association (EIA) developed most industry wide protocols. However, its influence over wireless communications has faded in recent years. Today, the IEEE is the major organization overseeing the development of wireless protocols. It has become popular because it develops open standards in a neutral forum, meaning that they can be freely implemented without any formal licensing agreements. Open standards are highly beneficial, as they promote compatibility and interoperability among products from different vendors and heed the development of new technologies by encouraging many companies to work on the same standard. They also reduce the risk to both consumers and vendors as both groups are assured widespread support for their product.
Currently, standards are being developed in two phases. The first phase is carried out by the IEEE and the second phase by an industry group. The IEEE typically develops the lower two layers (physical and data link) of the OSI 7 Layer Model and creates guidelines that are strictly technical in nature, while industry groups develop the upper layers and are more devoted to issues related to marketing the standard. This illustrates why there are two groups working on any one wireless technology, whether it is Bluetooth, ZigBee, Wi-Fi, or Ultra Wideband (UWB). For example, the IEEE has a working group for 802.15.1 (Bluetooth) and one for 802.15.4 (ZigBee) that specifies the lower two layers of their respective standards. However, Bluetooth also has an industry group called the Bluetooth SIG (Special Interest Group) comprised of companies such as Agere, Ericsson, IBM, Intel, Microsoft, Motorola, Nokia, and Toshiba. Similarly, as summarized in Figure 2.1, ZigBee formed the ZigBee Alliance, Wi-Fi the Wi-Fi Alliance, and Wireless USB the Wireless USB Promoter Group. If a standard needs to be updated, this is done in the form of amendments to the existing IEEE standards by the IEEE Standards Committee.
Standard / Technical Working Group / Industry GroupRFID
/ ISO / EPCglobalhttp://www.epcglobalinc.org
Wi-Fi / IEEE 802.11a/b/g/n / Wi-Fi Alliance
http://www.wi-fi.org
Bluetooth / IEEE 802.15.1 / Bluetooth Special Interest Group
http://www.bluetooth.org
ZigBee / IEEE 802.15.4 / ZigBee Alliance
http://www.zigbee.org
Wireless USB / IEEE 802.15.3a / Wireless USB Promoter Group
http://www.usb.org/wusb/home
Figure 2.1 Summary of Standards and their IEEE Industry Group
2.3 Survey of Short-Range Wireless Technologies
There are many wireless technologies available in today’s diverse market. Each has its own specific characteristics in terms of frequency, reliability, range, security, bandwidth, and cost. Bluetooth, ZigBee, Wireless USB, RFID, Wi-Fi and Wireless USB are all examples of short-range wireless technologies. Each wireless technology is intended for use in specific applications in various industries. The following section will discuss the features of each of these standards and show how they relate to their intended applications.
2.3.1 RFID
RFID is an older technology that was first used in combat situations during World War II to detect enemy or ally planes, but was only standardized during the 1990’s. RFID transmitters (called readers) work by sending out signals that are reflected back to the transmitting device by tags that are placed on an object. This technology is used to prevent automobile theft, collect tolls automatically, manage traffic, gain entrance to buildings, automate parking, pay at gas stations, control vehicle access, dispense goods, provide ski lift access, and track library books [2.1].
RFID technology differs from barcode technology in two ways. Unlike barcodes, RFID tags can store varying amounts of information, based on the amount of memory available on the RFID tag. The larger internal storage makes it possible for every item to have a unique tag that identifies the item and its history. Also, to read a barcode, one must scan the entire tag with a line of sight, whereas with RFID, all tags that are in the vicinity of a reader can be scanned.
Today there are two types of RFID tags on the market: passive and active. Passive tags are powered by using the electromagnetic power of incoming signals and therefore do not require an independent power supply. These tags have a reading range of up to five meters and cost about $0.40 (US) per tag. Active tags cost more, as they have their own power supply and have a reading range of over one hundred meters. Active tags cost between $0.40 and $6.00 (US), depending on their memory, packaging and frequency, but manufacturers are intent on lowering these prices. Low frequency handheld readers cost up to $100, high frequency between $200 and $300 (US), and ultra high frequency (UHF) between $1000 and $3000 (US).
One limitation of RFID is that some of its operating frequencies are restricted in certain countries. For example, a license is required to operate UHF (ultra high frequency) tags in most parts of the world. However, a few frequencies are unrestricted and can be used by all.
2.3.2 Wi-Fi
There are currently three major Wi-Fi standards available: 802.11a, 802.11b, and 802.11g. The main difference between 802.11a and 802.11b is how the IEEE defined the physical layers. 802.11a, 802.11b, and 802.11g transmit data at a rate of up to 54Mbps, 11Mbps, and 54Mbps respectively. 802.11a’s range is far smaller than that of 802.11b, and 802.11g has a larger range than its two predecessors.
Wi-Fi is commonly used in homes, offices and public buildings to provide wireless internet access to laptops and PDAs. It is primarily intended for high-bandwidth data applications such as streaming rich multimedia over the internet and transferring large files. It was designed as a wireless extension of traditional wireline networks. Wi-Fi is inexpensive, which has greatly contributed to its rapid adoption over the last few years [2.2]. The next generation of Wi-Fi, 802.11n, will be capable of transmitting data at over 100Mbps.
Wi-Fi has some limitations that designers should be aware of. One problem is interference, which will be discussed in section 4.3. Another issue is the high power consumption of Wi-Fi devices, which increases costs and reduces battery lifetime. Finally, Wi-Fi has several security flaws. These will be discussed in section 4.4.
2.3.3 Bluetooth
Bluetooth is intended to replace cables for personal devices such as cell phones, PDAs, keyboards, mice, headsets, and headphones. Bluetooth automatically connects up to eight devices within ten meters of each other into a Wireless Personal Area Network (WPAN). The selection of Bluetooth products is currently limited, but a more diverse family of devices will be released by 2006. Bluetooth’s acceptance among consumers has been hampered by its relatively high cost.