Resource Allocation for Uplink-Downlink Cellular Network with Small Cells and Relays Enhanced

With the rising demand of wireless network capacity and coverage, heterogeneous network consisting of Macro Base Stations (MBSs), Small-cell Base Stations (SBSs) and relay nodes (RNs) can be a promising technique which might be widely deployed in the future system framework. However, user throughput in heterogeneous network can be largely degraded by co-channel interference, which is brought by the reuse of frequency. In this paper, we study a general multi-cell heterogeneous network model, and propose a power-based classification criterion and a range-expansion-based association criterion to classify RNs and users, respectively. Based on these criterions, Cooperative MultiPoint (CoMP) transmission is utilized for some specific users. Afterwards, based on fairness metric, we formulate the resource allocation problem into a convex optimization problem. By adopting dual decomposition method, a closed-form solution is obtained. Finally, system level simulation is operated and the obtained results verify the advantageous performance of the proposed optimal resource allocation strategy.