PERFORMANCE EVALUATION OF DATA TRANSPORT OVER DIFFERENT-NODE DENSITY OF ZIGBEE SENSOR NETWORK – AN OPNET SIMULATION STUDY

In this paper, we analyze the performance of different node density of Wireless Sensor Network (WSN) operating under the IEEE Standard 802.15.4 in the beacon-enabled mode. The motivation for evaluating the beacon-enabled mode is due to its flexibility for WSN applications as compared to the non-beacon enabled mode. The analysis is based on an accurate OPNET simulation model which supports slotted Carrier Sense Multiple Access Mechanism with Collision Avoidance (CSMA/CA) mechanism and Guaranteed Time Slot (GTS). The performance of the slotted CSMA/CA sensor network is evaluated and analyzed for different network settings to understand the impact of the protocol attributes, including super-frame order (SO), beacon order (BO), data packet size and maximum back-off number. Through the simulation results, high SO provides better network throughput, otherwise results in lower average latency. We also found that the MAC overheads on small MAC Service Data Unit (MSDU) are more significant than the overheads on large MSDU. And the back-off mechanism results in longer delays when the network traffic is heavy.

A new methodology for designing of tactical integrated telecommunications and computer networks for OPNET simulation

This paper present a novel methodological approach in the design of integrated tactical telecommunications and computer networks for command information system and defining the elements for the OPNET simulation model. The elements proposed for design of network information architecture. For that purpose, the way established to set up relationships between elements that uses for network topologies design, building of network elements and network traffic. They are integrated with its parameters in the preliminary model defined by an OPNET simulation model. We propose the measure of efficiency for accomplishment of tactical command requirements to use the design model network. This measure of efficiency is mean time delay that described with mathematical relations, involving the communication parameters speed of generating traffic, packet size, link capacity and adequately reflects the projected network. Furthermore, the applications of the proposed approach and given instructions allow to designers full examination of the network architecture, and provide translation into preliminary model and design OPNET simulation model.