Competing Technologies
12.8.1 Bluetooth and the Infrared Data
Association
The Infrared Data Association (IrDA) specified three infrared
communication standards:
-
IrDA-Data
-
IrDA-Control
-
A new standard Alr
IrDA-Data is a similar technology to Bluetooth used as a
short-range wireless connectivity technology. It is a point-to-point, narrow
angle (30o clone) data communications standard specified to provide
wireless communication capabilities at distance of up to 1 meter and at data
rates of 9600 bps to 16 Mbps. It is currently used in several million devices,
primarily for cable replacement to exchange data using line-of-sight wireless
communications. It is incorporated in notebook computers, printers, mobile
phones, watches, medical equipment, and so on.
Bluetooth and IrDA may have overlapping functionalities, but
Bluetooth supports a wider set of applications than what is supported by the
IrDA. Both of the technologies use the same upper-layer protocol (OBEX) to
implement the common set of applications. In this way, Bluetooth ensured
interoperability with IrDA. IrDA has no security mechanisms defined, anyone can
snoop into data being exchanged between two devices. Line-of-sight
communications minimize such problems. In contrast, Bluetooth provides better
security by needing to perform authentication and then encrypt data exchanges.
Bluetooth, because of the use of spread spectrum radio frequency that enables
omni-directional multiple connections, overcomes the line-of-sight problem.
Further, Bluetooth has gained wider acceptance for use in numerous devices to be
built by many manufacturers.
12.8.2 Bluetooth and IEEE 802.11b
IEEE 802.11 specified related technology intended for
high-bandwidth wireless LAN applications. Because of the low-cost, low-power,
short-range operation at smaller data rates of 1 Mbps, Bluetooth does not
compete with the IEEE 802.11 WLAN technology. Bluetooth technology is intended
as WPAN usage and is intended to solve entirely different set of problems.
However, the operating spectrum for both technologies is in the same 2.4-GHz ISM
frequency band.
Due to this, although Bluetooth and 802.11b have completely
different technologies and distinct applications, they will have mutual
interference. The IEEE 802.11 charter had undertaken to study the coexistence
model and quantify the interference effects. The model results indicated a
reduction of network throughput and increase in network latency in both
Bluetooth and IEEE 802.11b. The coexistence mechanism currently under study
includes both the collaborative and noncollaborative mechanisms in sharing the
medium between the radios.
12.8.3 Bluetooth and IEEE 802.15
IEEE also initiated a similar technology interest and in early
1999 formed WG15 within 802 standards committee. The newly formed IEEE 802.15
group formed a charter for personal area networks (PANs) and solicited for
proposals. But Bluetooth SIG was the only respondent. Even though the Bluetooth
specifications do not meet the complete requirements of the IEEE 802.15 charter,
Bluetooth was accepted with some arrangements on the use of the specifications.
This adoption into IEEE validates the technology merits and ensures future
growth and development of Bluetooth.
Sections
