On Performance of Digital Radio Receiver in Non-Gaussian Interference
Licentiatavhandling, 2003
Interference from electrical equipment can degrade a co-located digital radio
receiver severely. To avoid this performance degradation it is necessary to have
estimation methods to predict the influence from an interference environment on
a radio receiver in advance. To protect radio services, electrical equipment
must fulfill international standards regarding maximum allowed levels of
radiated electromagnetic energy. Unfortunately, present emission requirements
are not developed to protect digital radio receivers. Furthermore, present
requirements are only defined for the frequency range below 1 GHz, why there is
a need for new emission requirements suitable to protect digital radio services.
In this work, the influence from electrical equipment on digital radio receivers
is considered. Since interference generated from electrical equipment often has
a non-Gaussian character, the commonly used Gaussian approximation is not always
applicable for performance analysis. For this issue, a practical method to
estimate the performance degradation is necessary.
The amplitude probability distribution (APD) has earlier been shown to be an
applicable measure of an interference signal in order to be correlated to its
impact on a digital radio receiver. In this thesis, the usage of this measure in
conventional error expressions is clarified. It is also shown that this
relationship between the measured APD of an interference source and the maximum
degradation of the receiver can be deployed for emission requirements. The
direct use of the measured APD of an interference source for the performance
estimation of the radio system requires that the bandwidths of the measuring and
the radio receiver under investigation are approximately the same. When this is
not the case a solution for how to convert the APD measured by one bandwidth to
be valid for a bandwidth according to the receiver under investigation. The
conversion of the APD to another bandwidth is developed for a certain type of
noise.
bandwidth conversion
performance estimation
APD
interference
minimum shift keying
man-made noise
Gaussian approximation
measurement
emission requirements
non-Gaussian interference
micro-wave oven
MSK
amplitude probability distribution
emission