Energy-Efficient Dynamic Point Selection for Cloud Radio Access Networks (C-RAN)

Cloud-RAN (C-RAN) is a promising network architecture for next-generation wireless communications. C-RAN separates computation entities, i. e., Baseband Units (BBUs) from base stations (BSs), and puts BBUs in a cloud located at a centralized network. With C-RAN, user equipments (UEs) can receive data from multiple collaborative cells and thus can leverage the dynamic point selection (DPS) technology to improve network efficiency. To save the energy of UEs, 3GPP LTE-A has defined the Discontinuous Reception (DRX) mechanism to allow UEs to turn off their radio interfaces and go to sleep in a periodical manner. However, how to cooperate DRX with DPS under the C-RAN architecture is still an open issue. Therefore, this paper addresses the resource allocation problem in C-RAN by asking how to optimize the energy conservation of UEs based on DRX while reserving sufficient bandwidths for UEs considering their quality-of-service (QoS) in C-RAN with DPS. To solve this problem, we propose an energy-efficient DPS scheduling scheme. The key idea of our scheme is to serve the UEs in the intersection of cells continuously and allocate resource tightly to avoid additional wake-up intervals. Extensive simulation results show that our scheme can serve more UEs while enhancing throughput and reducing their energy consumption as compared to the existing schemes.