Cooperative communication system by exploiting multiple relay nodes (RN) offers significant performance improvement in terms of coverage and capacity. However, using all available RNs in the network is not optimal. Some RNs are located far from user equipment (UE), or having bad link quality due to fading and shadowing. Therefore, only several RNs with good link quality to the UE need to be chosen. Furthermore, in a high user density network, bandwidth is limited which requires proper resource allocation. In addition, each UE has different traffic demand to be satisfied. There are scenarios where eNodeB (eNB) and RN are wasting their resources to UE with low demand, whereas the resources can be used for different UE to compensate for its high demand. In this project, joint problem of relay and bandwidth assignment in a network with heterogeneous user traffic are studied. Accordingly, a Spectral-efficiency and Demand-based Joint Relay and Bandwidth Assignment (SE-D-JRBA) scheme is proposed which is flexible for network with diverse user traffic demands. Numerical evaluation is analyzed for SE-D-JRBA with full-duplex (FDX) and half-duplex (HDX) RN and decode-and-forward (DCF) operation, hence compared to system without relay cooperation. The results demonstrated that the proposed method obtained good system efficiency and fairness.