Motorola PTP 400 Series Manual De Usuario
112
8.3.8 Spectrum
Management
Spectrum Management Selection (also referred to by the acronym DFS) is the PTP 400
Series Bridge wireless feature that monitors the available wireless spectrum and directs both
ends of the wireless link to operate on a channel with a minimum level of co-channel and
adjacent channel interference.
8.3.8.1 Wireless Channels
The PTP 400 Series Bridge operates using a set of predefined channels. Section 5 ”General
Considerations” contains detailed information on this subject with regards each product
variant. It should be noted that some product variants have a channel raster smaller than their
channel size. In these cases the channels overlap and the Spectrum Management displays
should be read accordingly.
The default channelization can be modified by varying the lower center frequency attribute in
the installation wizard – see Section 8.3.5.3 “Wireless Configuration” - Lower Center
Frequency.
8.3.8.2 Spectrum Management Measurements
The PTP 400 Series Bridge performs four Spectrum Management measurements per TDD
cycle, per channel. The measurements are subdivided into two signal peak measurements
and two mean signal measurements. The peak measurements represent the peak received
signal power with a resolution down to 100 ns. The mean measurement represents the mean
received signal power for the 40
μs measurement period.
The Spectrum Management algorithm collects measurements equally from all channels. This
process is called the Channel Availability Check (hereafter referred to by the acronym CAC).
The CAC uses a round-robin channel select selection process to collect an equal amount of
measurements from each channel. It is important to note that the CAC measurement process
is not altered by channel barring process. Measurements are still collected for all channels
irrespective of the number of barred channels.
8.3.8.3 Measurement Analysis
Spectrum Management uses statistical analysis to process the received peak and mean
measurement. The statistical analysis is based on a fixed, one minute, measurement
quantization period. Spectrum Management collects data for the specified quantization period
and only at the end of the period is the statistical analysis performed.