Radar Avoidance - Motorola PTP 250 User Manual

PTP 250 User Guide

Radar avoidance

In regions where protection of radars is part of the local regulations, the PTP 250 must
detect interference from radar-like systems and avoid co-channel operation with these
systems.
To meet this requirement, the PTP 250 implements the following features:
ETSI regulations
The regulations have radar detection requirements for both master and slave devices.
The requirements for a master device are:
•
The device can only transmit on available channels, of which there are none at initial
power up. The radar detection algorithm will always scan a usable channel for 60
seconds (channel availability check) for radar interference before making the channel
an available channel.
•
As a result of this compulsory channel scan, there is a service outage of at least 60
seconds every time radar is detected, and the installation time is extended by at least
60 seconds even if no radar is detected on the channel.
•
When operating on a channel, the spectrum monitoring algorithm implements a radar
detection function (in-service monitoring) which looks for impulsive interference on the
operating channel. If impulsive interference is detected, spectrum management will
mark the current operating channel as having detected radar (unavailable channel) and
initiate a channel hop to an available channel. The previous operating channel will
remain in the unavailable state for 30 minutes after the impulsive interference pulse
was detected.
•
After the 30 minutes have expired the channel will be returned to the usable channel
pool.
•
There is a secondary requirement for bands requiring radar avoidance. Regulators
have mandated that products provide an approximately even loading of the spectrum
across all devices. In general, this prevents operation with fixed frequency allocations.
However, ETSI regulations do allow frequency planning of networks (as that has the
effect of spreading the load across the spectrum).
The Master device will not initiate any transmissions on channels which overlap the band
5600-5650 MHz as the radar detection requirements are more severe.
phn-2182_003v004 (Oct 2011)
UNDER DEVELOPMENT
Wireless operation
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