Direct/Cooperative AF Relay Switching Using Spectrum Division/Adaptive Subcarrier Allocation For SC-FDMA Uplink

Abstract— In this paper, we propose a direct/cooperative amplify-and-forward relay (D/AR) switching using a spectrum division/adaptive subcarrier allocation (SDASA) for increasing the uplink capacity of single carrier-frequency division multiple access (SC-FDMA). In the D/AR switching, switching between direct communication and cooperative AF relay is done so that the channel capacity is maximized. In the SDASA, the transmit SC signal spectrum is divided into sub-blocks, to each of which a different set of subcarriers (resource block) is adaptively allocated. We evaluate the achievable channel capacity by the Monte-Carlo numerical computation method. It is shown that the proposed D/AR switching can reduce the transmit power by about 4 (2) dB compared to the direct communication (the cooperative AF relay) for the 1% outage capacity of 4.0bps/Hz. Also shown is that the D/AR switching using SDASA can further reduce the transmit power by about 2dB compared to the D/AR switching without SDASA.