On releasing two general assumptions for decode-and-forward cooperative communications

In wireless communications, the application of cooperation techniques can offer additional spatial diversity. With the decode-and-forward (DF) protocol, it can be shown that the error-rate performance can be much improved in the fading channel environment. However, two strong assumptions are generally required: 1) The included relay can exactly know the correctness of its decision; 2) the destination can also know whether the relay forwards its decoded signal. Obviously, these may not be possible in many cases. In this paper, we utilize some specially-designed methods from detection theory to release these assumptions. Simulations show that through employing the proposed methods, the DF protocol still works well without applying the two assumptions, and the resultant error-rate performance can be quite close to that of the perfect DF scenario.