Probabilistic random multiple access procedure model to the CSMA/CA type medium

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.