The control-data separation architecture (CDSA) has been regarded as a promising solution to effectively manage the heterogeneous network (HetNet) in the fifth-generation mobile communication systems. Thus, this study investigates the resource allocation problems in CDSA-based HetNet. To meet various requirements of data transmission, the authors first present a new framework with flexible resource management and efficient traffic control. In this framework, the control-data transmission supported by macro cell evolved nodeB is time-sensitive and continuous with high reliability. On the basis of it, a traffic-aware resource allocation approach is proposed to improve the resource efficiency. Once the traffic-congestion requirements of the pattern are satisfied with the minimum spectrum, the throughput of small cells is simultaneously maximised due to orthogonal spectrum between macro and small cells by using this approach. Moreover, the traffic-congestion analytical result is elaborately derived in terms of current network state. Three adaptive resource allocation schemes for implementing this approach are also designed with different complexities. Numerical results validate the accuracy of the proposed analytical method, and also indicate that the traffic-aware resource allocation approach is more efficient than the static one.