  We propose a novel multiple-access technique to overcome the shortcomings of
the current proposals for the future releases of Long-Term Evolution (LTE). We
provide a unified radio access system that efficiently and flexibly integrates
both traditional cellular services and machine-to-machine (M2M) connections
arising from Internet-of-Things (IoT) applications. The proposed solution,
referred to as multi-service oriented multiple access (MOMA), is based on a)
establishing separate classes of users using relevant criteria that go beyond
the simple handheld-IoT device split, b) service-dependent hierarchical
spreading of the data signals and c) a mix of multiuser and single-user
detection schemes at the receiver. Signal spreading in MOMA allows to handle
densely connected devices with different quality-of-service (QoS) profiles and
at the same time its flexible receiver structure allows to allocate the
receiver computational resources to the connections that need it most. This
yields a scalable and efficient use of the available radio resources and a
better service integration. While providing significant advantages for key
future communications scenarios, MOMA can be incorporated into LTE with a
limited impact on the protocol structure and the signaling overhead.
