Wpływ odległości pomiędzy urządzeniami w sieci ZigBee na parametry transmisyjne na dystansie do 100 metrów w otwartej przestrzeni

Publikacja przedstawia opracowany system mikroprocesorowy, służący do pomiaru zależności efektywnego czasu transmisji od odległości pomiędzy urządzeniami w sieci ZigBee, wyniki uzyskanych pomiarów oraz nowatorski sposób opisu opóźnień komunikacyjnych w sieci bezprzewodowej za pomocą modelu probabilistycznego. Opracowany system pozwala również na badanie innych parametrów transmisyjnych. Jego głównym zadaniem jest pomiar czasu pomiędzy wysłaniem pakietu danych, a informacją z modułu odbiorczego potwierdzającą odbiór.

This paper presents a microprocessor system for measuring the influence of a distance between ZigBee network devices on the effective transmission time. The system was developed by the authors. The measurement results obtained are given. A new way of communication delays in a wireless network is described. The developed system allows studying the effects of various obstacles in the transmission, in particular the impact of suppression of free space. The measuring system consists of a microcontroller to supervise the broadcasting and receiving data. Its main task is to measure the time between sending a data packet and receiving information from the module confirming receipt. The measurement result is stored in a file in real time. The system is easy to use. The XBee ZigBee and XBee-Pro modules by Digi International were used for taking measurements. They provide live coverage of two or more elements of the final network, allowing for the construction of wide area networks based on star and mesh configuration. A new probabilistic model was used to describe the delay. It allows you also to save the delay as well as the relative number of packets received during each transmission and retransmission of the data. The model is simple to implement in simulation programs. The data obtained from measurements show that increase in the distance between the modules has an impact on the number of retransmission and lost data packets. This enables designating certain guidelines to aid the design of a wireless network.