S. A. Dadenkov – Ph.D. (Eng.), Associate Professor, Department of Automatics and Telemechanics, Perm National Research Polytechnic University

E-mail: dadenkov@rambler.ru

E. L. Kon – Ph.D. (Eng.), Professor, Department of Automatics and Telemechanics, Perm National Research Polytechnic University

The article studies the characteristics of an information control network with a random multiple access algorithm with carrier control and collision avoidance by predicting the network load of the predictive p-persistent CSMA channel. A significant advantage of the algorithm in comparison with other algorithms of the class of random multiple access is dynamic adaptability of the transmission persistence level to the channel load. This is achieved using an advanced mechanism for predicting the expected network load for each data transfer cycle. The result is decrease in channel access time at low load and a reduced likelihood of data collisions at high load. The algorithm is widely used in fieldbus networks, including the sensor and industrial networks of LonWorks and BacNet. A literary review shows the interest of the world community to application of the algorithm, for which research and modernization of its mechanisms are actively conducted. The purpose of this work is to study the influence of the law of the distribution of the number of slots of competition for access to a channel on the probabilistic and temporal characteristics of data transmission in a network with the slot access algorithm studied. The paper presents a brief description of the principles of operation of the studied access algorithm and describes the structure of the developed and used model in the simulation environment AnyLogic. The necessary simulation experiments of the functioning of the network with the services of reliable and unreliable message delivery have been carried out using three different laws for choosing the slots of rivalry (uniform, normal, exponential). The analysis of the obtained characteristics of the network operation has been made and conclusions have been given about the impact of the laws of choice of access slots on the duration of transmission and the probability of data loss for various network channel loads and delivery services. Recommendations on the expediency of applying various laws for choosing access slots have been formulated.

1. Olifer V.G., Olifer N.A. Komp'yuternye seti. Printsipy, tekhnologii, protokoly. Ucheb. dlya vuzov. Izd. 4-e. SPb.: Piter. 2010.
2. Control network protocol specification ANSI/CTA-709.1-D. United States. 2014 [Elektronnyj resurs]. URL: https://webstore.ansi.org/ standards/cea/cea7092014ansi (data obrashcheniya: 02.12.2018).
3. Ditrikh D., Loj D., Shvajntser G.Yu. LON-tekhnologiya, postroenie raspredelennykh prilozhenij. Per. s nem. pod red. O.B. Nizamutdinova. Perm': Zvezda. 1999.
4. Moshe K. Collision resolution simulation for distributed control architectures using LonWorks. IEEE International Conference on Automation Science and Engineering. Edmonton. 2005. P. 319–326.
5. Miśkowicz M. Analysis of mean access delay in variable-window CSMA. Sensors. 2007. V. 7. № 12. P. 3535–3559.
6. Miśkowicz M. Access delay in LonTalk MAC protocol. Computer Standards & Interfaces. Nederland: Elsevier Science Publishing Company. 2009. V. 31. № 3. P. 548–556. DOI: 10.1016/J.CSI.2008.03.025.
7. Miśkowicz M. Average channel utilization of CSMA with geometric distribution under varying workload. IEEE Transactions on Industrial Informatics. 2009. V. 5. № 2. P. 123–131. DOI: 10.1109/TII.2009.2017524.
8. Buchholz P., Plonnigs J. Analytical analysis of access-schemes of the CSMA type. Proc. of IEEE International Workshop on Factory Communication Systems WFCS. Wien. 2004. P. 127–136.
9. Dadenkov S.A. The simulation of p-persistent CSMA algorithm of unequal random multiple access. Radio Electronics, Computer Science, Control. 2018. № 2 (45). P. 98–107. DOI: 10.15588/1607-3274-2018-2-11.
10. Dadenkov S.A., Kon E.L., Chmykov V.V. Imitatsionnaya model' promyshlennoj seti (na primere tekhnologii LonWorks). Materialy XV Mezhdunar. nauch.-tekhn. konf. «Problemy tekhniki i tekhnologii telekommunikatsij». Kazan': Izd-vo Kazan. gos. tekhn. un-ta. 2014. S. 82–84.