Implementation and Performance Evaluation of IEEE 802.15.4 Protocol

Abstract: In recent years, wireless sensor networks have attracted great interest of both academy and industry due to the wide range of contexts in which they can be used. Considering the large number of applications and huge-scale deployments wireless sensor networks have been envisioned, standardization is a critical issue to guarantee the interoperability among platforms. The IEEE 802.15.4 has become the most notable standard for wireless sensor networks and many software and hardware platforms are based on it. The implementation and performance analysis of this standard is essential to understand the fundamental limitations of it. Moreover, evaluation tools play an important role to test new algorithms and other protocols based on this standard. Simulation is one the most valuable tools in protocol prototyping design and evaluation. Although there are many simulators available for wireless networks, many of them are not user-friendly programmable. On the other side, MATLAB becomes very popular in different fields since it provides a powerful and easy to use environment. However, the number of wireless sensor network simulators built on it is scarce. In this thesis, a new simulator is developed using MATLAB for IEEE 802.15.4 protocol which combines simplicity and accuracy. The performance of the simulator in terms of packet delivery rate and average delay is compared with an analytical model that considers all the key aspects of the standard. The simulator also provides a graphic user interface that allows the user to define and draw network topologies. Moreover, the simulator includes a debugging tool which permits to see graphically the 802.15.4 PHY and MAC events occurred during the simulation. This allows the user to analyze the underlying communication among the nodes. Furthermore, although some practical software implementations of IEEE 802.15.4 protocol are available, there is no explicit comparison with their theoretical bound of the network performance. TKN15.4 is the most advanced software implementation. However, its validation through theoretical models has not been studied before. The performance of TKN15.4 is evaluated and compared with the proposed analytical model. The impact of the known clock drift is also analyzed for TKN15.4. Significant misalignments of the slot boundaries and loss of beacon frames are observed, resulting in a certain gap with the theory.