Recent advances have resulted in the ability to integrate sensors, wireless communications and digital electronics into a single integrated circuit package. This capability is enabling networks comprised of very low cost sensors nodes that are able to communicate with each other. Energy efficient wireless communications is an essential requirement for Wireless Sensor Networks (WSN) in many environmental monitoring applications and there is a growing need to improve the lifetime of wireless sensor nodes. The power consumed by node transceiver electronics is non-negligible and has a major impact on battery life. This paper describes a system level methodology to analyze a complete RF transceiver architecture for short-range energy limited applications requiring high data rates. The overall system specifications are derived using system level simulations utilizing Matlab programming and Agilent's Advanced DesignSystem. The obtained specifications can be used for implementing an energy efficient transceiver at 2.4GHz for WSN applications.