# 5.6 Reliability and usability

In this context we will define reliability as the ability of a technology to perform its intended function, without failure, under stated conditions and for a stated period of time. It is beyond the scope of this course to provide a detailed comparison of the reliability of WiFi and Bluetooth – we simply want to alert you to some of the issues. Broadly these are:

- What is the likelihood of data errors being introduced during transmission?

- How well does the technology recover from such errors?

- What is the likelihood of system failure?

- How does the technology perform in terms of availability of service?

Bluetooth and WiFi both operate within the unlicensed ISM band of radio frequencies which is shared by other devices – cordless phones and microwave ovens, for example. Interference from other devices operating at the same or close frequencies is a potential problem as this can introduce transmission errors. So an issue here concerns the resistance of each technology to this kind of interference. In particular, a Bluetooth network could be operating within range of other Bluetooth networks (for example, a Bluetooth headset could be communicating with a mobile phone in the vicinity of a computer sending data to a printer via a Bluetooth link).

To see why microwave ovens operate in the ISM band, look back at Figure 6 in Section 2.6. Notice how there is an overlap between the higher frequencies in the radio spectrum and the lower frequencies in the microwave spectrum. This occurs between about 109Hz (1 GHz) and 1010Hz (10 GHz). The ISM frequency band sits around 2.4 GHz.

Issues about usability include questions such as:

- How easy is it to install, set up and maintain the technology?

- How easy is it to use?

- What is the quality of product support?'

Again, it is beyond the scope of this course to compare these issues for WiFi and Bluetooth, but points to consider would be how easy it is to access the network and connect to other devices.

OpenLearn - IT: device to device communication
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