Resource management in 5G: A tale of two timescales

To attain the targeted data rates of next generation (5G) cellular networks requires dense deployment of small cells, in addition to macro cells which provide wide coverage. Dynamic radio resource management (RRM) is crucial to the success of such heterogeneous networks due to much more pronounced traffic and interference variations in small cells. This work proposes a framework for RRM organized according to two timescales, which includes 1) centralized RRM on a second/minute timescale corresponding to typical durations of user sessions, and 2) distributed RRM on a millisecond timescale corresponding to typical latency requirements. An optimization problem is formulated for the slower timescale with consideration of (distributed) opportunistic scheduling on the faster timescale. An iterative algorithm is developed to solve the optimization problem efficiently for a small cluster of cells. Numerical results demonstrate advantages of the dual-timescale RRM framework.