RESEARCH OF AUDIO AND VIDEO TRAFFIC THE CHARACTERISTICS IN LOW-BANDWIDTH RADIO COMMUNICATION NETWORKS

Abstract

The construction of mass service systems, namely automated control systems, requires preliminary analysis and modeling of traffic in their communication networks. Mathematical models of various types of traffic have been developed for public networks, which allows to estimate the necessary functional characteristics of equipment for building a communication network, depending on the number of users. Low-bandwidth communication networks, which are built on the basis of ultra high frequency and very high frequency (UHF/VHF) radio stations, are distinguished by low speed, high delay and jitter of data transmission. To work in such communication networks, special data transmission protocols are adapted and developed. In this paper, a study of the characteristics of audio and video traffic in low-bandwidth communication networks is carried out, which are built on the basis of UHF/VHF radio stations, which will allow creating a software implementation of simulated traffic modeling for the further determination of the services availability at the stage of planning and designing the communication system. Two personal computers and two modern RF‑7850M-HH UHF/VHF radio stations were used to study the characteristics of audio traffic. The radio stations worked in three operating modes: narrowband mode with a fixed carrier frequency FF, narrowband mode with pseudo-random adjustment of the operating frequency QL1A, and wideband mode ANW2C. The voice was transmitted in digital mode using the built-in MELP 2400 codec, and the "iperf-v2.0.5" software was used to determine the characteristics of the audio traffic on personal computers connected to these radio stations. Two personal computers, two modern RF‑7850M‑HH UHF/VHF radio stations, a video encoder and a video camera were used to study video traffic characteristics. The radio stations operated in ANW2C broadband mode. To evaluate the characteristics of the video traffic, the Wireshark software was used on a personal computer, with the help of which the video broadcast from the video encoder was presented. It was found that voice transmission in low-speed communication networks based on UHF/VHF radio stations occupies a bandwidth of 2 Kbit/s - 2.5 Kbit/s, and when voice and data are simultaneously transmitted in radio stations, data buffering and jitter increase. The resolution, bitrate, FPS, and necessary bandwidth of video traffic that can be transmitted via UHF/VHF radio communication channels are determined. Based on the conducted research, recommendations are provided for the transmission of video traffic through low-bandwidth communication channels.