Adaptive modulation
ePMP 3000 can transport data over the wireless link using several different modulation modes ranging
from 256-QAM to QPSK. For a given channel bandwidth and TDD frame structure, each modulation mode
transports data at a fixed rate. Also, the receiver requires a given signal-to-noise ratio to successfully
demodulate a given modulation mode. Although the more complex modulations such as 256-QAM will
transport data at a much higher rate than the less complex modulation modes, the receiver requires a
much higher signal-to-noise ratio.
ePMP 3000 provides an adaptive modulation scheme where the receiver constantly monitors the quality
of the received signal and notifies the far end of the link of the optimum modulation mode with which to
transmit. In this way, optimum capacity is achieved at all times.
Radar avoidance
In regions where the protection of radars is part of the local regulations, ePMP must detect interference
from radar-like systems and avoid co-channel operation with these systems.
To meet this requirement, ePMP implements the following features:
âš«
The equipment 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 for radar
interference before making the channel an available channel.
âš«
This compulsory channel scan will mean that there is at least 60 seconds service outage every
time radar is detected, and that the installation time is extended by at least 60 seconds even if
there is found to be no radar on the channel.
There is a secondary requirement for bands requiring radar avoidance. Regulators have mandated that
products provide a uniform loading of the spectrum across all devices. In general, this prevents operation
with fixed frequency allocations. However:
âš«
ETSI regulations do allow frequency planning of networks (as that has the same effect of
spreading the load across the spectrum).
âš«
The FCC does allow channels to be avoided if there is actual interference on them.
Encryption
ePMP supports optional encryption for data transmitted over the wireless link. The encryption algorithm
used is the Advanced Encryption Standard (AES) with a 128-bit key size. AES is a symmetric encryption
algorithm approved by U.S. Government organizations (and others) to protect sensitive information.
Country codes
Some aspects of the wireless operation are controlled, enforced, or restricted according to a country
code. ePMP country codes represent individual countries (for example Denmark) or regulatory regions
(for example FCC or ETSI).
Country codes affect the following aspects of wireless operation:
To Next Page
Loading...
Need help?
General
