  We propose a novel random multiple access (RMA) scheme with quality of
service (QoS) guarantees for machine-to-machine (M2M) communications. We
consider a slotted uncoordinated data transmission period during which machine
type communication (MTC) devices transmit over the same radio channel. Based on
the latency requirements, MTC devices are divided into groups of different
sizes, and the transmission frame is divided into subframes of different
lengths. In each subframe, each group is assigned an access probability based
on which an MTC device decides to transmit replicas of its packet or remain
silent. The base station (BS) employs successive interference cancellation
(SIC) to recover all the superposed packets. We derive the closed form
expressions for the average probability of device resolution for each group,
and we use these expressions to design the access probabilities. The accuracy
of the expressions is validated through Monte Carlo simulations. We show that
the designed access probabilities can guarantee the QoS requirements with high
reliability and high energy efficiency. Finally, we show that RMA can
outperform standard coordinated access schemes as well as some of the recently
proposed M2M access schemes for cellular networks.
