It is a common experience for us to use infrared (IR) signalling to change channels on a TV via a TV remote. IR signals depend on a line-of-sight transmission path between the sender and receiver. This has in fact hindered the application of IR from advancing beyond remote controlling and peripherals connection. IR signals occur at very high frequencies, in the 300- to 300,000-Ghz range, just above the visible spectrum of light.
Table 1.2 offers a comparison of the common wireless networking standards, their ranges and throughputs.
|
Standard |
Frequency range |
Theoretical maximum throughput |
Effective throughput (approximate) |
Average geographic range |
|---|---|---|---|---|
|
802.11b ("Wi-Fi") |
2.4 GHz |
11 Mbps |
5 Mbps |
100 meters (or approximately 330 feet) |
|
802.11a |
5 GHz |
54 Mbps |
11–18 Mbps |
20 meters (or approximately 66 feet) |
|
802.11g |
2.4 GHz |
54 Mbps |
20–25 Mbps |
100 meters (or approximately 330 feet) |
|
Bluetooth ver. 1.x |
2.4 GHz |
1 Mbps |
723 Kbps |
10 meters (or approximately 33 feet) |
|
Bluetooth ver. 2.0 |
2.4 GHz |
2.1 Mbps |
1.5 Mbps |
30 meters (or approximately 100 feet) |
|
IrDA |
300–300,000 GHz |
4 Mbps |
3.5 Mbps |
1 meter (or approximately 3.3 feet) |
Source: Dean 2006. 4e
Now, read the following material to learn more about wireless network protocols:
Reading
Dean (2010) 373–83.
To see if you have understood the topics we have covered so far, attempt Self-test 2 on your own before checking the Suggested answers to Self-test 2.
In practice, 802.11b and 802.11g wireless transmission technologies are more commonly used in business LANs than Bluetooth. Can you think of some underlying reasons? Complete Activity 2 and take a look at its Feedback to Activity 2 afterwards.
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