  In this paper, we propose systematic block Markov superposition transmission
of repetition~(BMST-R) codes, which can support a wide range of code rates but
maintain essentially the same encoding/decoding hardware structure. The
systematic BMST-R codes resemble the classical rate-compatible punctured
convolutional~(RCPC) codes, except that they are typically non-decodable by the
Viterbi algorithm due to the huge constraint length induced by the
block-oriented encoding process. The information sequence is partitioned
equally into blocks and transmitted directly, while their replicas are
interleaved and transmitted in a block Markov superposition manner. By taking
into account that the codes are systematic, we derive both upper and lower
bounds on the bit-error-rate~(BER) under maximum {\em a posteriori}~(MAP)
decoding. The derived lower bound reveals connections among BER, encoding
memory and code rate, which provides a way to design good systematic BMST-R
codes and also allows us to make trade-offs among efficiency, performance and
complexity. Numerical results show that:~1)~the proposed bounds are tight in
the high signal-to-noise ratio~(SNR) region;~2)~systematic BMST-R codes perform
well in a wide range of code rates, and~3)~systematic BMST-R codes outperform
spatially coupled low-density parity-check~(SC-LDPC) codes under an equal
decoding latency constraint.
