  Sparse code multiple access (SCMA) building upon orthogonal frequency
division multiplexing (OFDM) is a promising wireless technology for supporting
massive connectivity in future machine-type communication networks. However,
the sensitivity of OFDM to carrier frequency offset (CFO) poses a major
challenge because it leads to orthogonality loss and incurs intercarrier
interference (ICI). In this paper, we investigate the bit error rate (BER)
performance of SCMA-OFDM systems in the presence of CFO over both Gaussian and
multipath Rayleigh fading channels. We first model the ICI in SCMA-OFDM as
Gaussian variables conditioned on a single channel realization for fading
channels. The BER is then evaluated by averaging over all codeword pairs
considering the fading statistics. Through simulations, we validate the
accuracy of our BER analysis and reveal that there is a significant BER
degradation for SCMA-OFDM systems when the normalized CFO exceeds 0.02.
