A Channel-Insensitive Link Quality Model for Adaptive Coding and Modulation in Satellite Communications

Modern terrestrial and satellite communication systems use some form of link adaptation to improve the overall system efficiency and achieve higher data rates with no increase in bandwidth. Adaptive Coding and Modulation (ACM) is a common link adaptation technique used to mitigate destructive propagation effects and improve overall system efficiency by dynamically changing the communication mode according to the channel characteristics. A robust mode selection algorithm is key to an efficient ACM protocol. It requires a link quality model to estimate the decoder performance as a function of the instantaneous channel condition. In this paper, a channel-insensitive link quality model is developed together with a heuristic mode selection algorithm for ACM. The proposed link quality model uses an Information Outage Probability (IOP) bound for channel quality measurement and accurate performance prediction. The heuristic mode selection algorithm is tested and demonstrated via computer simulations using the 5G New Radio (NR) Low-Density Parity-Check (LDPC) code as the coding scheme in a system operating under a non-stationary frequency-flat fading channel profile.