cooperative communication with scheme selection

In this paper, a new cooperation scheme is provided that implements the advantages of both DF and AF schemes to enhance the performance in wireless networks. We suppose that nodes can access to the channel information and based on this, the cooperation scheme is selected and applied. This algorithm is repeated when channel states have an effective variety. We apply this strategy to a single relay system with square MQAM signals where optimum power allocation is employed. Simulations and comparisons verify that symbol-error-rate (SER) performance can be improved properly.