  The cognitive radio networks are an emerging wireless communication and
computing paradigm. The cognitive radio nodes execute computations on multiple
heterogeneous channels in the absence of licensed users (a.k.a. primary users)
of those bands. Termination detection is a fundamental and non-trivial problem
in distributed systems. In this paper, we propose a termination detection
protocol for multi-hop cognitive radio networks where the cognitive radio nodes
are allowed to tune to channels that are not currently occupied by primary
users and to move to different locations during the protocol execution. The
proposed protocol applies credit distribution and aggregation approach and
maintains a new kind of logical structure, called the virtual tree-like
structure. The virtual tree-like structure helps in decreasing the latency
involved in announcing termination. Unlike conventional tree structures, the
virtual tree-like structure does not require a specific node to act as the root
node that has to stay involved in the computation until termination
announcement; hence, the root node may become idle soon after finishing its
computation. Also, the protocol is able to detect the presence of licensed
users and announce strong or weak termination, whichever is possible.
