Abstract:
Nowadays the issue of digital radio network security during destructive
impacts by intruder is particularly important. For destructive impacts on physical OSI level
prevention noise protection methods are applied and encryption is applied on network and
higher levels. In fact most dangerous vulnerabilities from destructive impacts are focused
on digital radio network channel level in procedures random multiply access procedure to
the digital radio network medium. Only for procedure of random multiply access to digital
radio network of S-ALOHA type math models have been developed which allow to
estimate it functionality efficiency in conditions of potentially destructive impacts. This
procedure applies for GSM, TETRA, DMR, LTE digital radio networks. But for Wi-Fi and
Bluetooth networks, which are used currently in every house, random multiply access
procedure for CSMA/CA is used. The paper presents a math model of the procedure for
random multiple access to the digital radio networks of CSMA/CA type. The model take
into consideration potential destructive intruder impact by analytic expression adjusting for
probabilistic and time characteristic in well-known model and because of usage new
indicator — network channel occupancy probability. In Wi-Fi and Bluetooth networks in
case of channel occupancy due reason collisions and successfully transfer delay timer for
each abonent terminal is stopped. In well-known models this feature of digital networks
with random multiply access to CSMA/CA is not considered. It established that existing
CSMA/CA random multiply access algorithm functioning efficiency tends to zero because
of possible destructive impacts. Work results can be used in the digital radio network OSI
channel level automatic recovering efficiency area of algorithm development.
Keywords:digital radio network, destructive impact, procedure of random multiple access to environment, CSMA/CA, Markov chain, effective functioning.
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