Specifications
43
transmit approximately 10m and Class 3 uses up to 1mW of power and can
transmit approximately 1m.
Like any protocol, there are drawbacks and problems with Bluetooth. Bluetooth
has problems with wall penetration, which is a major concern for our system.
Bluetooth also uses more power for the distance the data is traveling compared
to ZigBee. Another drawback is that other house appliances, like wireless home
telephone, ZigBee and Wi-Fi signals clutter the 2.4 GHz ISM band. This could be
a problem when dealing with noise corrupting packets of data being sent. The
Bluetooth protocol has a way to deal with this type of interference and limiting
those problems. Users using Bluetooth must also initiate a pairing between the
devices initial, making more work later for the end user. Overall though, it looks
like using the Bluetooth protocol is not the best solution for our system.
2.6.5 IEEE 802.11 – Wi-Fi
IEEE 802.11 (Wireless Local Area Network) protocol is the most widely used and
recognized computer related wireless communication system. The term Wi-Fi ®
is a registered trademark of the Wi-Fi Alliance ® and is often used as a synonym
for IEEE 802.11 technology. This protocol has been constantly upgrading and
developing since its release in 1999. The availability of Wi-Fi® microchips for
embedded devices along with its wide range of use makes IEEE 802.11 an
excellent option to consider for our system. The 802.11 protocol has a few
network standards that are compared in Table 7 below.
802.11
Protocol
Release
Frequency
(GHz)
Bandwidth
(MHZ)
Approx.
range
indoors
(meters)
Approx.
range
indoors
(feet)
-
June 1997
2.4
20
20
66
a
Sept.
1999
5
20
35
115
b
Sept.
1999
2.4
20
38
125
g
June 2003
2.4
20
38
125
n
Oct. 2009
2.4 / 5
20 / 40
70
230
Table 7 802.11 Network Standards
Before determining if Wi-Fi® is the way to go, we must first analyze the
capabilities of Wi-Fi® to see if it will meet the requirements of our project. Some
of the capabilities of Wi-Fi® include excellent range. The IEEE 802.11 b
protocol‟s typical range of 38 m (125ft) is more than enough distance required by
our system. 802.11 b also has throughput up to 11 Megabytes per second