Ultra-dense small cells operating in a cooperative manner, such as cloud radio access network (C-RAN), have been introduced to serve the numerous mobile devices in the next generation wireless networks. One of the major challenges in efficiently operating the C-RAN in a cooperative manner is the excessive overhead signaling and computation load, such as downlink channel state information (CSI) acquisition at the cloud for cooperative downlink transmission, which scales rapidly with the size of the network. In this paper, the exploitation of mobility information of devices is proposed to address the challenge of efficiently operating the C-RAN. We introduce a mobility-assisted CSI acquisition method to complement conventional pilot-based CSI acquisition methods. This method enables the C-RAN to avoid excessive overhead signaling. A low-complexity algorithm is designed to maximize the sum rate of all devices subject to the limits of backhaul capacity and base station transmit power. An adaptive algorithm has also been proposed to improve the robustness against channel uncertainty. Both theoretical and numerical analyses show that the exploitation of mobility information provides a new dimension to improve conventional transmission schemes for next-generation massive cooperative networks.