关键词: 通信技术, 多速率调制, 空时分组码, 多天线系统

Abstract: A multiple-rate modulation scheme based on the automatic repeat request (ARQ) protocol was proposed to achieve Shannon capacity in spacetime coding systems. In this scheme, modulation bit rate was determined at the receiver for each packet according to the channel state information (CSI) and was conveyed back to the transmitter. If the channel fading is so deep that even one bit can not be afforded, the ARQ protocol was used for a retransmission. The analysis of the proposed scheme proves that the throughput only depends on the average transmit SNR and the product of transmit antenna number and receive antenna number. The throughput expression was derived and its limitation was proved to be the Shannon capacity. The simulation results show that this scheme largely outperforms the constant schemes.

Key words: communication, multiplerate modulation, space-time block coding, multipleantenna system