LAUSR

In the last decade, the number of wireless devices in the 2.4 GHz band has grown rapidly, such as WiFi, Bluetooth, ZigBee and IEEE 802.15.4. Because of the technologies and the number of devices continues increasing, the probability of spectrum saturation is high. The implementation of the Cognitive Radio (CR) proposes an alternative to reuse spectrum, in order to guarantee a peaceful coexistence with the other technologies operating in the same frequency band. The contribution of this paper can be listed as follows: i) proposes a study to verify the performance of the IEEE 802.15.4 standard in mobile e-Health scenarios and its capacity with multiple mobile source nodes in the network, in intention to evaluate its capacities to support cognitive radio directives, through an OMNeT++ simulation and physical embedded devices test bed, both results showed a high correlation. The novelty of this study is the introduction of mobile nodes (which simulate mobile patients inside one hop WSN topology). ii) The results obtained in section IV B, show that in the best case of the study, was obtained a 14.5% packets losses by collisions with five mobile source nodes, which is 13.5% greater than the 1% allowed by the standard. In addition, the percentage of packets lost by the backoff algorithm has an important increase from eight up to ten mobile source nodes, demonstrating the impact of the number of nodes has on the performance of the network. iii) Concluding, the implementation of CR will improve the performance in WSN IEEE 802.15.4, through dynamic multi-channel operation avoiding the spectrum saturation problem.