Channel Assignment in Wireless Mobile Ad Hoc Networks ◾ 261
(clusters). In this scheme, the collision-free intracluster communications are organized by the
cluster heads using a TDMA scheme, and a CDMA scheme is overlaid on the TDMA to organize
the interference-free intercluster communications. A CDMA/TDMA scheme reduces the required
number of codes to the number of clusters, which is significantly less than that of a CDMA
scheme. To design a CDMA/TDMA scheme for clustered wireless ad hoc networks, we encounter
the following three intricate problems. e first problem is dividing the network into a minimum
number of nonoverlapping clusters. e second problem is to assign an interference-free code to
each cluster considering the concept of ...