An efficient ARQ scheme for multi-carrier modulation systems based on packet combining

An efficient ARQ scheme based on the packet combining technique is investig ated for multi-carrier modulation systems. In multi-carrier modulation syst ems, several subcarriers are used for high data rate transmission and their individual received signal quality becomes different from one subcarrier t o others in a frequency selective fading channel. Therefore by changing the assignment of data to the sub-carriers in the retransmission packets, the distortion between the previous transmitted packet and the newly retransmit ted one will be different. This is the principle of the proposed adaptive d ata order rearrangement for a packet combining ARQ scheme, which can achiev e more diversity gain in packet combining and improve the ARQ performance. From the results of the theoretical analysis and the computer simulation, i t is confirmed that the proposed packet combining ARQ with the proposed ope ration can achieve the better performance in terms of the average packet tr ansmission success probability. In addition, this proposed scheme is also c ompared with the conventional multi-carrier modulation ARQ scheme based on the partial retransmission of a packet. The computer simulation results dem onstrate that the proposed scheme has also advantage against the latter one , and it is considered to be as a more efficient ARQ scheme for multi-carri er modulation systems.