Performance of Terminal-Collaborated MIMO Reception System Leveraging Multiple Decision Results

This paper deals with a terminal-collaborated MIMO reception technique, in which nearby terminals collaborate to receive MIMO signals from the base station. This system can improve the transmission performance because the number of received signals used for decoding can be expanded by sharing the MIMO signals from the base station among nearby mobile terminals. In this paper, we focus on the fact that the amount of traffic for transmission of the decision result is generally smaller than that of the received signal waveform. We assume multiple helper terminals that forward waveforms within a collaboration group and multiple detection terminals that perform decoding. In this system, there is a possibility that the degradation of decoding performance caused by decreasing the number of received signal waveforms transmitted can be improved by exchanging decision results among the detection terminals. The residual interference coefficients in frequency-domain iterative equalization are employed as important information for the reliability of the decision result. The decoding performance is improved by selecting the decision result with high reliability as the final decoding results. We evaluated the effects of the number of helper terminals and the number of detection terminals on the transmission performance and the amount of collaboration traffic by computer simulations. As a result, the improved transmission performance was confirmed with a slight increase in the amount of collaboration traffic.