TITLE:
A Cross Layer Optimization Based on Variable-Power AMC and ARQ for MIMO Systems
AUTHORS:
Shu-Ming Tseng, Wei-Shun Lei
KEYWORDS:
Transmitter Power Control, Spectrum Efficiency
JOURNAL NAME:
International Journal of Communications, Network and System Sciences,
Vol.3 No.5,
May
31,
2010
ABSTRACT: To improve spectrum efficiency (SE), the adaptive modulation and coding (AMC) and automatic repeat request (ARQ) scheme have been combined for MIMO systems. In this paper, we add variable power subject to power constraint in each AMC mode. We use KKT optimization algorithm to get the optimal transmit power and AMC mode boundaries. The numerical results show that the average SE is increased by about 0.5 bps/Hz for 2 × 2 MIMO systems with Nakagami fading with parameter m = 2 when SNR is around 15 dB and the ARQ retransmission is twice.