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Monitoring RF Signal-to-Noise Ratio


Signal-to-noise ratio (SNR) is a measure of the level of a desired signal against the level of background noise, measured in decibels (dB). Think of having a conversation in an empty restaurant where your signal (your voice) is clearly heard. Now, think of that same restaurant at noon, when the background noise (all other conversations) is at a peak. You will need to talk louder and lean closer to be heard at noon. In other words, you must increase your signal to overcome the background noise.

Signal-to-noise ratio, along with the bandwidth and channel capacity of a communication channel, affects throughput (see Monitoring RF Throughput), especially video throughput.

To view the signal-to-noise ratio on a radio over a fixed period of time:

  1. Select Monitor Mode in the Network Director banner.
  2. Select any view from the View pane.
  3. Expand the wireless list in the View pane, then select a radio.

    The Monitor mode RF tab becomes available when you select a radio. The Signal-to-Noise Ratio monitor becomes available only when you select a radio.

  4. Click the Monitor mode RF tab to view the four basic monitors for radios, which includes the Signal-to-Noise Ratio monitor.

    By default, the populated Signal-to-Noise Ratio monitor graph uses throughput that the selected object has experienced over the last hour.

  5. Optionally, change the timeframe covered by the monitor by selecting a different time from the list.
  6. Click Help (?) for help interpreting the throughput chart or see Signal-to-Noise Ratio Monitor.

To change the polling interval for monitors, see Setting Up User and System Preferences.

If you are using MSS version 8.0 or higher, you can try using Transmit beam-forming (TxBF) to improve your SNR values. TxBF is a technique that uses an array of transmitting antennas to send radio signals with adjusted magnitude and phase at each antenna to achieve a focused beam target to the receiver. TxBF can increase the Signal-to-Noise Ratio (SNR) at the receiver and improve performance. This feature is supported on the WLA532, WLA321, and WLA322, and is configured from the MSS CLI.