Cooperative Communication in Wireless Uplink Transmissions Using Random Network Coding

In this paper, we propose a novel multiuser cooperative communication scheme using random network coding for uplink wireless transmissions. The participating users transmit a linear combination of their new data packet and the packets successfully decoded due to preceding transmissions by other users, thus sending the new information as well as relaying the information for other users at the same time. The coefficients used for linear combination are selected at random from the finite field used to carry out the network coding. At the base station, original data packets are recovered from the received packets by solving the system of linear equations in the finite field. The proposed scheme is very robust against inter-user channel noise and can offer very high diversity gain in moderate inter-user channel conditions. Moreover, the transmission delay required by the proposed scheme is 2N as compared to N² in the traditional Time Division Multiple Access (TDMA) cooperative systems. The performance benefits of the proposed scheme are demonstrated through simulation analysis.