Nowadays Wireless Networks have an important impact in many activity domains. Due to the hardware and bandwidth limitations of these networks, resource allocation represents an important issue, being in the same time a very active research area. Considering the complexity of the wireless networks, analytical solutions are hard to be found. Hence, simulation becomes the most used methodology and OMNeT++ proves to be a very useful tool for investigation. This paper presents our work concerning the performance of different resource allocation techniques for EGPRS and Wireless Sensor Networks.