Energy-Efficient Dynamic Resource Allocation for Opportunistic-Relaying-Assisted SC-FDMA Using Turbo-Equalizer-Aided Soft Decode-and-Forward

In this paper, we exploit the benefits of the diversity gains that arise from a cluster of opportunistic relays (ORs) and from the independently fading subcarriers of multiple users. Our goal is to improve the energy efficiency of the decode-and-forward-based OR-assisted single-carrier frequency-division multiple-access (SC-FDMA) uplink, where the direct transmission (DT) link is unavailable. We proposed two joint dynamic resource allocation (JDRA) schemes by assuming that the pilot-aided channel-quality information (CQI) of all the users may be exchanged. Furthermore, we take the following two main aspects into account: 1) “first-hop quality awareness” (FHQA) for JDRA-aided OR and 2) “buffering delay awareness” in the context of interleaver-aided channel-coded systems. In addition, frequency-domain turbo equalizers are employed in both the relay and BS´s receivers. Our results demonstrate that, compared to the DT benchmarker, the proposed FHQA JDRA schemes can achieve an energy reduction gain of 91% for a single-antenna base station (BS) receiver and up to 7.4% for a multiantenna BS when considering the energy consumption due to CQI exchange among relays.