Effectiveness Evaluation of Random and Defined Subscriber Access Mechanisms to a Broadband Satellite Communications Network

Relevance. The increase in the number of terminals and the intensity of connections in satellite communication networks with the «star» topology actualizes the problem of choosing an effective mechanism for accessing a common radio channel. The well-known approaches of deterministic and random access have significant limitations. At the same time, there are no clear analytical criteria for choosing between mechanisms depending on the load, which makes it difficult to optimize network performance.

Purpose (research): The aim is to compare the effectiveness of two mechanisms for entering satellite terminals into a network with the "star" topology: with specific slot access and with random access. The assessment is aimed at identifying conditions under which one of the mechanisms is superior to the other in key performance indicators.

Methods. The solution of the problem is based on a combination of analytical and simulation modeling. To evaluate the effectiveness of random access, a strict combinatorial derivation of the mathematical expectation formula for the number of slots selected by exactly one terminal was carried out. The verification of the analytical model was performed using stochastic modeling in Python.

Result. A validated analytical model has been obtained that makes it possible to accurately predict the effectiveness of the random access mechanism. The data obtained is applicable in the design of satellite communication networks to optimize terminal entry time and channel resource allocation. The novelty elements are rigorous analytical inference and verification of the formula for the mathematical expectation of the number of successfully occupied slots with random access, which allows you to accurately predict performance without large-scale modeling. The novelty also includes the establishment of a quantitative criterion for choosing an access mechanism. The proposed model takes into account the real conditions of terminal competition for channel resources and is applicable to the analysis of protocols such as ALOHA and TDMA.

Practical significance. The presented solution is proposed to be used in the design and adaptive management of the MAC layer in VSAT satellite networks, IoT systems and telemetry networks. The obtained criteria for selecting an access mechanism can be implemented as dynamic reconfiguration algorithms in software-configurable networks, allowing automatic switching between modes depending on the current load. This will ensure optimal use of bandwidth, minimize delays, and increase overall network stability.

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