Wireless Sensor Networks - Network Coded Cooperative Communication : Design and Implementation

Abstract: This thesis is concerned with the design and implementation of a testbed for network coded cooperative communication (NC-CC) in IEEE 802.15.4-based wireless sensor networks (WSNs). The work and test are based on Contiki 2.5 and sensor nodes Zolertia Z1. In the testbed, a new network framework with large extensibility is provided, as well as a basic realization of NC-CC. In our implementation, CC is realized as a Rime primitive in Contiki, while NC is inserted as a new layer between Rime and MAC to perform opportunistic coding. In this way the network stack of Contiki is extended while still keeping the backward compatibility. Because of the lack of multicast in IEEE 802.15.4 protocol and the contradiction of applying continuous overhearing on power-constraint  sensor nodes, new mechanisms called pseudo overhearing and pseudo multicast is proposed in our testbed. A configurable test program is also designed for the purpose of evaluation. A combination of two senders, one relay and one destination is used as our network model. Experiments show that all the designed functions work properly. But to be robust, more experiments under different models should be brought in the future. A more detailed report  on the experiments can be found in my project-partner  Yitian Yan’s thesis.