  In this paper, we compare the finite-length performance of protograph-based
spatially coupled low-density parity-check (SC-LDPC) codes and LDPC block codes
(LDPC-BCs) over GF(q). In order to reduce computational complexity and latency,
a sliding window decoder with a stopping rule based on a soft bit-error-rate
(BER) estimate is used for the q-ary SC-LDPC codes. Two regimes are considered:
one when the constraint length of q-ary SC-LDPC codes is equal to the block
length of q-ary LDPC-BCs and the other when the two decoding latencies are
equal. Simulation results confirm that, in both regimes, (3,6)-, (3,9)-, and
(3,12)-regular non-binary SC-LDPC codes can significantly outperform both
binary and non-binary LDPC-BCs and binary SC-LDPC codes. Finally, we present a
computational complexity comparison of q-ary SC-LDPC codes and q-ary LDPC-BCs
under equal decoding latency and equal decoding performance assumptions.
