scholarly journals Evaluation of characteristics of wireless sensor networks with analytical modeling

In this paper, a mathematical model of the operation process of the ZigBee standard wireless network for remote monitoring systems based on the Markov chain apparatus was developed. Using the model was evaluated of the operation process of the CSMA/CA algorithm of the MAC level of the IEEE 802.15.4 ZigBee standard. The peculiarity of this mathematical model is that it takes into account the level of loading of network elements and potential distortions in the transmitted packets as a result of the influence of interference. Using the developed mathematical model, the main characteristics of the network operation process, such as dependence of the probability of successful transmission of packets on the system load (on the number of nodes), the dependence of the bandwidth on system load (on the number of nodes) for the case where there is noise in the channel and for the absence of noise in the channel were obtained.

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5694
Author(s):  
Rogério Casagrande ◽  
Ricardo Moraes ◽  
Carlos Montez ◽  
Francisco Vasques ◽  
Erico Leão

Node mobility in multi-hop communication environments is an important feature of Wireless Sensor Network (WSN)-based monitoring systems. It allows nodes to have freedom of movement, without being restricted to a single-hop communication range. In IEEE 802.15.4 WSNs, nodes are only able to transfer data messages after completing a connection with a coordinator through an association mechanism. Within this context, a handover procedure needs to be executed by a mobile node whenever there is a disconnection from a coordinator and the establishment of a connection to another one. Many applications, such as those found in health monitoring systems, strongly need support for node mobility without loss of data during the handover. However, it has been observed that the time required to execute the handover procedure is one of the main reasons why IEEE 802.15.4 cannot fully support mobility. This paper proposes an improvement to this procedure using a set of combined strategies, such as anticipation of both the handover mechanism and the scan phase enhancement. Simulations show that it is possible to reduce latency during the association and re-association processes, making it feasible to develop WSN-based distributed monitoring systems with mobile nodes and stringent time constraints.


1998 ◽  
Author(s):  
JOhn W. Lemons ◽  
Michael C. Vorwerk ◽  
Joe H. Carroll ◽  
William E. Jabour

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