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Communications Quality
Communications Quality
Communications quality is measured by the Signal to Noise Ratio (SNR). The SNR is a
dynamic indicator that indicates the relative strength of the radio signal (signal level) versus
the radio interference (noise level) in the radio signal path. In most environments, SNR is
a good indicator for the quality of the radio link between transmitter and receiver. A higher
SNR value means a better quality radio link.
The RoamAbout Client Utility allows you to monitor the SNR, signal level, and noise level
at the client. The Client Utility is provided on the RoamAbout 802.11 PC Card Drivers and
Utilities CD-ROM, or you can download it from the RoamAbout Wireless web site.
For the AP, the RoamAbout AP Manager provides a Link Test diagnostic tool that monitors
the SNR, signal level, and noise level between the AP and a remote wireless device.
Signal Level
The signal level values give you an indication of the distance between wireless devices.
Using the RoamAbout Client Utility, you can observe a decrease of the signal level value
when you move a client away from its AP. As an indicator for the communications quality,
signal level should always be interpreted in combination with noise level:
• A high signal level with a low noise level provides excellent communications quality.
• A high signal level with a high noise level results in an average or poor SNR.
Communications may not be as good as expected despite the strong signal level.
• A low signal level may still provide adequate communications when the noise level is
relatively low.
Noise Level
The noise level indicates the presence of interference. Noise can be generated by various
devices such as microwave ovens (2.4 GHz), elevator motors, and theft detection devices
(like those used in retail stores). Noise level should always be related to the signal level:
• A low noise level with a high signal level provides excellent communications quality.
• A medium or high noise level with a high signal level results in an average or poor
SNR. Communications may not be as good as expected despite the strong signal level.
• A high noise level most likely provides poor communications when the signal level is
medium or low.