## Control Systems and Computers, N2, 2018, Article 8

Upr. sist. maš., 2018, Issue 2 (274), pp. 80-86.

UDK 621.39

Anatolii P. Voiter, Dr. Sc. (Technology), Deputy Director, Institute for Nuclear Research  National Academy of Sciences of Ukraine, pr.Nauky,47, Kyiv, 03028, Ukraine, voiter@kinr.kiev.ua

EFFECTIVENESS OF ADAPTIVE MANAGEMENT OF PACKETS  LENGTH IN RADIO NETWORKS OF THE DATA TRANSMIT

Introduction. A mathematical model is described for calculating the effective transmission rate at the channel level of radio networks using an adaptive CSMA protocol with variable length of data packets, taking into account the influence of the error rate in the radio channel and the packet format.

Purpose. The aim of the work is to determine the efficiency of the channel level of radio networks using an adaptive CSMA protocol with variable packet length and a rigid access strategy to the radio channel, taking into account the limitations on the length of packets on the part of the LLC protocol and the physical layer.

Methods. An equation is obtained for the effective transmission rate as a function of the physical transmission rate in the radio channel, the probability of successful transmission of the packet for a given error rate in the radio channel, the packet structure, and the probability of a contention-free CSMA protocol with adaptive packet length control.

Results. The mathematical model makes it possible to calculate the optimal size of data packets for LLC protocol and its allowable increase in adaptive CSMA protocol procedures, the effective transmission rate at the channel layer of the packet radio network, and its throughput. It is shown that the efficiency of the considered adaptive CSMA protocol in its integrated use is limited at the level 30% of its potential.

Conclusion.  The proposed mathematical model can be used for  practical implementation of adaptive control of length of the packet in radio networks of data transmission in order to optimize the effective transmission rate.

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