In this paper, we analyze the decode-and-forward cooperative multihop transmission. Different from conventional multihop transmission, each node achieves the spatial diversity by combining all the independently fading symbols from previous nodes on the route line. We consider the possibility for the relay node to forward error-detected symbols, and propose an adaptive transmission protocol to compensate for it. The bit error rate is derived for the cooperation system, and the comparison with the conventional multihop transmission shows that this system can achieve full diversity order. Practical cooperative range and the impact of relay nodes distribution on the system performance are discussed for the practical implementation.