  In this paper, we propose joint sequencing and scheduling optimization for
uplink machine-type communication (MTC). We consider multiple
energy-constrained MTC devices that transmit data to a base station following
the time division multiple access (TDMA) protocol. Conventionally, the energy
efficiency performance in TDMA is optimized through multi-user scheduling,
i.e., changing the transmission block length allocated to different devices. In
such a system, the sequence of devices for transmission, i.e., who transmits
first and who transmits second, etc., has not been considered as it does not
have any impact on the energy efficiency. In this work, we consider that data
compression is performed before transmission and show that the multi-user
sequencing is indeed important. We apply three popular energy-minimization
system objectives, which differ in terms of the overall system performance and
fairness among the devices. We jointly optimize both multi-user sequencing and
scheduling along with the compression and transmission rate control. Our
results show that multi-user sequence optimization significantly improves the
energy efficiency performance of the system. Notably, it makes the TDMA-based
multi-user transmissions more likely to be feasible in the lower latency
regime, and the performance gain is larger when the delay bound is stringent.
