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In the case of NBN all jamming energy is placed into single channel, where
activity of a communication system was detected.
B. Tone jamming
The next mentioned technique is tone jamming. In this type of jamming one
or several tones are placed in the spectrum. When there is used only one tone,
only one frequency is disrupted. If multi tones are applied, the tones are placed at
previously chosen frequencies.
C. Swept jamming
Swept jamming technique is similar to broadband or partial-band noise
jamming. Jamming can be realized by using narrow tone signal or PBN signal.
In this technique relatively narrowband signal is sweeping across part of spectrum.
As a result of this, at any instant of time, only part of interesting band is jammed.
D. Pulse jamming
Pulse jamming is similar to partial band noise jamming. The main factor
of pulse jamming is so called duty cycle, which means how long the jammer is switch
on relative to switch off. The results of jamming strictly depend on the peak power
and value of duty cycle.
E. Smart jamming
Smart jamming exploits weak sides of particular network, such as e.g. GSM
or UMTS. Technique is based on assault on vulnerabilities e.g.: error correction
checksums, messages related with acknowledgements, synchronization channels,
time slots. Identification of a network type and synchronization in time are crucial
for successful jamming. Known methods of attack include among others: station
overloading, preventing positive call initiation, preventing from achieving connectivity,
forged calls to the subscribers, disrupting communications by introducing
errors into checksums, or distortions in messages related with acknowledgements.
In this type of a jamming, the knowledge of transmission protocol is the key issue.
F. Following jamming.
Following jamming is usually applied against frequency hopping transmission.
Such jammer search for emissions and when the signal is detected, it is jammed.
The jammer follows carrier frequency changes of transmitted signal and continues
jamming.