Cooperative communications in mobile ad hoc networks

Cooperative communications is a special case of a broader class of transmission protocols. It considerably improves the network connectivity. The two wireless network models of mobile ad hoc networks (MANET) are a MANET with an existing clustered infrastructure and a MANET in which a random source conveys extra control information and link parameters in the message. In a cluster-based MANET, all terminals communicate through a cluster head or access point (AP). Clustering can help connectivity by essentially increasing the area in which to search for new neighbors. In an infrastructure-less network a source can include an appropriate preamble sequence to provide a request for cooperation as well as the sync signal. Individual relays are treated as physical layer resources rather than network layer entities.