Traffic Adaptation and Energy Saving Potential of Centralized Radio Access Networks with Coordinated Resource Allocation and Consolidation

In this paper, we investigate traffic adaptation and energy saving potential of centralized radio access networks (C-RAN) with coordinated resource allocation and consolidation (CoRAC). The proposed CoRAC scheme comprises dynamic base-band unit-remote radio unit (BBU-RRU) mapping and cooperative dynamic downlink/uplink (DL/UL) reconfiguration. Specifically, in our proposed scheme, the logical connections between BBUs and RRUs are adaptively adjusted according to the traffic condition and interference patterns. Cell clusters are correspondingly formed, on which the developed cooperative reconfiguration method is conducted. With this setup, the DL/UL configurations are no longer determined with respect to an individual cell, but are chosen in form of the cluster-specific configuration patterns (CPs) with optimized performance metrics. Our proposed CoRAC scheme is custom designed for time-division duplex (TDD) systems aiming at (1) asymmetric traffic adaptation with load balancing; and (2) cross-subframe co-channel interference (CCI) management. In addition to (1) and (2), the CoRAC is beneficial from the perspective of network energy savings. This is because by shutting down under-utilized BBUs and selecting appropriate DL/UL configurations for traffic adaptation, the power consumption of both BBUs and RRUs (in terms of per-subframe radiated transmission power) can be reduced. System level evaluation results are provided, which show that by employing our proposed scheme, remarkable performance improvements can be obtained relative to the existing methods, in terms of the packet throughput, traffic adaptation and power consumption.