Abstract
This report addresses marketing and technical issues of WPANs as well as their
applications. This is the second issue of the report; information is updated
and the analysis of the Near Field Communications (for WPAN applications) is
added.
WPANs represent a significant shift in wireless networking technology, which
has generally been targeted at devices like laptops where power consumption is
not a major issue. WPAN technology emphasizes constructing reliable links over
low-power radios, but often at the cost of a reduced data rate compared to
Wi-Fi. The networks define a new paradigm - the user becomes
“enveloped” by a network bubble, which “attached” to a
user and moves along with his/her movements.
Wireless networking standards like 802.11b and 802.16 typically focus on
providing PC-to-PC or PC-to-ISP connectivity over the range of a building or
even a metropolitan area. However, many applications have far less stringent
range requirements, such as connecting peripherals wirelessly to a mobile
device or adding components to a home theater system. Wireless Personal Area
Networks are a perfect fit for these applications: they offer a wide variety
of data rates, low power consumption and are supported by several transmission
technologies.
In this report, we discussed the following approaches to WPAN radio:
- ZigBee
- NFC
- UWB, and
- Bluetooth.
802.15.4 (ZigBee) is exchanging rate of transmission for power. 802.15.4 radio
offers data rates of up to 250 Kb/s, and can easily support links with a very
low duty cycle. Hence, it is suitable for deployment in battery-powered
devices that must survive for up to several years between charges/changes of a
power supply. 802.15.4 has already found wide acceptance in the wireless
sensor network community, and used also in WPANs for a variety of applications.
NFC technology is evolving as a leading technology for very short distances of
communications. Near Field Communication is a standards-based, short-range
wireless connectivity technology that enables simple and safe two-way
interactions among electronic devices. NFC technology allows consumers to
perform contactless transactions, access digital content and connect devices
with the simplicity of a single touch. WPAN and Body WPAN applications of this
technology are becoming very important.
UWB radios emit low-power, high-bandwidth pulses that deliver data rates
comparable to wired Ethernet (100 Mb/s and up). Its high data rates and low
power consumption make it ideal for replacing short wired links.
Unfortunately, IEEE standardization of UWB has failed (so far), resulting in
two incompatible standards: DS-UWB that was advocated by the UWB Forum; and
MB-OFDM, advocated by the WiMedia Alliance. The UWB market is still immature,
but already includes WPAN applications.
The early entry into the WPAN paradigm, Bluetooth, has already been widely
deployed in hundreds of millions of devices. It offers data rates of up to 3
Mb/s and ranges of up to 100 m, with far lower power consumption than 802.11b.
Its middleware layer builds on top of the PHY and MAC layers to provide a high
degree of interoperability among Bluetooth-equipped devices. This low power
consumption and interoperability guarantee have fueled Bluetooth' s acceptance
in the WPANs. It is important to note the days of the 802.15.1 radio layer may
be numbered. The Bluetooth SIG has recently announced plans to abandon the
802.15.1 PHY and MAC layers in some future version of the Bluetooth standard,
and instead to deploy the middleware components on top of a variant of the
WiMedia UWB standard (though now it is revising this direction in favor of the
802.11n technology). Depending on how the radio stack is implemented, this
shift may increase Bluetooth' s data rate by many times, cutting power
consumption.
This report also shows that WPAN technologies are in the process of
development and research, and such technologies as NFC and Wibee are examples
to this statement. Enhancements of low-powered wireless technologies that we
are witnessing in the resent years made it possible to talk even about such
transmission environments as a human body (Wireless Body Area
Networks-IEEE802.15.6), where information is coded, for example, by changes in
the skin characteristics.
The report also discusses a variety of WPAN applications: from home automation
to homeland security and first responders' communications; and examines
marketing issues of WPAN and applicable radio technologies that support this
class of network.
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