This paper proposes the MRC-MMSE (Maximal Ratio Combining - Minimum Mean Squared Error) detection of the space time coding over Decode and Forward (DF) cooperative network channel with 16 states binary Rate 2/4 convolutional code. As we employed this convolutional code rate and Alamouti space time scheme, the transmitted signal can be created by two QPSK modulators instead of 16 - PSK or 16-QAM technique. When relay node has detection error, the system is biased. MRC-MMSE detection can reduce this effect. Numerical results show that the proposed technique significantly reduces error rate performance. Additionally, this technique does not require any bandwidth expansion.