  This work presents a novel K-Repetition based HARQ scheme for LDPC coded
uplink SCMA by employing a network coding (NC) principle to encode different
packets, where K-Repetition is an emerging technique (recommended in 3GPP
Release 15) for enhanced reliability and reduced latency in future massive
machine-type communication. Such a scheme is referred to as the NC aided
K-repetition SCMA (NCK-SCMA). We introduce a joint iterative detection
algorithm for improved detection of the data from the proposed LDPC coded
NCKSCMA systems. Simulation results demonstrate the benefits of NCK-SCMA with
higher throughput and improved reliability over the conventional K-Repetition
SCMA.
