An improved unicast retransmission scheme based on network coding

In view of problems such as low efficiency and low spectrum efficiency existed in wireless unicast retransmission, an improved unicast retransmission scheme based on network coding was proposed. The basic principle of the scheme is that transmitting terminal encodes initial incorrect transmission data packet and new data packet by different rate respectively in retransmission stage, combines the data packets, and transmitting terminal sends the hybrid information to the corresponding receiver. The receiver uses soft combining method to combine the retransmitted data packet with the initial packet during the previous transmission stage and then makes a decoding process in order to recover the original information, at the same time, the combined two packets will share energy, space and time in the retransmission process. The simulation results show that performance of error bit rate of the proposed scheme is lower than the traditional automatic repeat request scheme, and the proposed scheme improves transmission efficiency of wireless unicast link effectively.