A peak power efficient cooperative diversity using star-QAM
Koji Ishibashi, Won-Yong Shin, Hyo Seok Yi, Hideki Ochiai · 2011
In this paper, we propose a new simple relaying strategy with bit-interleaved convolutionally coded star quadrature amplitude modulation (QAM). Star-QAM is composed of multiple concentric circles of phase-shift keying (PSK). Exploiting this property, a hard limiter is used to enhance power amplifier (PA) efficiency at a relay. We analyze our proposed cooperation in terms of asymptotic pairwise error probability (PEP) and show that it can achieve the full diversity order conditioned on that the minimum free distance dfreeof the convolutional codes is large enough. Finally, theoretical results and effectiveness of PA efficiency are confirmed by computer simulations.