Aiming at the problems of relay node’s communication capacity and the energy consumption of the whole networks which are always ignored by the existing algorithms

many constraint conditions are introduced into the existing model of fault-tolerant relay node placement in this paper

such as the irreversible factor in the forwarding paths and relay node’s communication capacity.And a new evaluation standard is presented

and it is based on the minimum distance factor of communicating network.A hybrid relay node placement algorithm based on enumeration and greedy optimization algorithm is implemented in solutions.The simulation result demonstrates the algorithm can limit the communication capacity conveniently of the relay node.Compared with other placement algorithms

improvement of energy-efficiencies in this algorithm is obvious.