  A novel concept of Joint Source and Channel Sensing (JSCS) is introduced in
the context of Cognitive Radio Sensor Networks (CRSN). Every sensor node has
two basic tasks: application-oriented source sensing and ambient-oriented
channel sensing. The former is to collect the application-specific source
information and deliver it to the access point within some limit of distortion,
while the latter is to find the vacant channels and provide spectrum access
opportunities for the sensed source information. With in-depth exploration, we
find that these two tasks are actually interrelated when taking into account
the energy constraints. The main focus of this paper is to minimize the total
power consumed by these two tasks while bounding the distortion of the
application-specific source information. Firstly, we present a specific slotted
sensing and transmission scheme, and establish the multi-task power consumption
model. Secondly, we jointly analyze the interplay between these two sensing
tasks, and then propose a proper sensing and power allocation scheme to
minimize the total power consumption. Finally, Simulation results are given to
validate the proposed scheme.
