network is divided into clusters in the hierarchical structure,
such as each cluster consists of a cluster head and a plurality
of cluster members. In the high level network and clustering,
the formation of a greater level of the network is until the
most advanced. A hierarchical structure, cluster head node
is responsible for forwarding data between clusters. The
frequency of a hierarchical network, different level by the
communication of different frequency. The communication
range of the lower nodes is small, and the top node to cover
a large range. Advanced node is at multiple levels, multiple
frequency, and it realizes the communication of different
levels with different frequency.