A hierarchical radio resource management scheme for next generation cellular networks

Next generation cellular networks are envisioned to widely enable machine-to-machine (M2M) communication. For many applications in the M2M domain, deterministic communication latencies and high reliability are of very high importance. As a consequence, device-to-device (D2D) communication is a expected to play a key role in order to avoid from having to route the entire data through a centralized base station. Considering the large number of devices but relatively small payload lengths of many M2M applications, LTE currently fails to efficiently utilize the available radio resources. This is primarily because the granularity of resources that can be allocated to a single user is too coarse, resulting in parts of the allocation being wasted. In this paper, we present a hierarchical radio resource management scheme that allows ordinary cellular users to reuse and exploit the otherwise unused portion of a D2D scheduling grant. We show that our resource reuse scheme improves the uplink throughput of cellular users between 10% and 30%, depending on the actual number of D2D users, compared to current allocation schemes.