Wireless sensor network is an important emerging field and a lot of research has been performed on this area. Several theoretical studies have being done and simulated data is available while the real time data in real environments is less commonly available for qualitative analysis. The main reason for the lack of real time data is that only few sensor network test-beds are available and the other reason is the time required to perform experiments on real sensors besides quality of the collected data. The main aim of this book is to present a qualitative comparison of DSA based channel surfing schemes and time methods. As Wireless medium has been congested it is difficult for low power devices such as sensors to transmit data reliably. Channel surfing schemes exploit spectrum holes and enable sensors to opportunistically transmit data even in heavily interfered conditions. The performance metrics used are energy spent per packet, energy spent on channel sensing and amount of data being transmitted. This book addresses all the researchers working in the area of wireless sensor networks and need an insight on the behavior of different DSA based schemes in real time environments.