Throughput optimized error-free transmission using optimum combination of AMC and ARQ based on imperfect CSI

A new scheme for error-free transmission is presented which uses optimized combination of adaptive modulation and coding (AMC) and automatic repeat request (ARQ). Using conventional error correction codes with finite length, a limited value of packet error rate (PER) is inevitable. More powerful codes with more extra parity bits results in lower PER, however, at the cost of more transmit power per bit which is limited by average power constraint. Remained erroneous packets may be detected by error detection codes and be substituted by retransmission request in ARQ. However, when error correction capability is weak, throughput decreases due to increase of required retransmissions. In this article a method for optimum combination of error correction codes in AMC and error detection codes in ARQ is provided. In practice, due to estimation error and time variant channels, noisy and outdated channel state information (imperfect CSI) is available which restricts providing exact instantaneous PER constraint. To satisfy instantaneous PER constraint based on imperfect CSI, a novel technique is designed in this paper. Numerical evaluations indicate the efficiency of the proposed design.