CoMP in Heterogeneous Networks: Low-Complexity Joint Cooperative Resource Allocation with SDMA

Coordinated multipoint transmission (CoMP) is considered for a heterogeneous network where different kinds of base stations (BS) are located. We focus on joint cooperative resource allocation including linear transceiver design and user scheduling with the goal of maximizing the weighted sum rate in the downlink of a multiple-input multiple-output orthogonal frequency division multiple access (MIMO-OFDMA) system, where each frequency resource can be allocated to multiple users at a given time instance, i.e., space division multiple access (SDMA) is enabled. Furthermore, we consider the case where multiple streams are allocated per user. Since the optimal solutions are extremely computationally complex to obtain, we introduce some scheduling metrics for selecting the most suitable subsets of users on each subchannel and propose a suboptimal joint resource allocation algorithm using these metrics. The proposed algorithm is able to take linear per-BS power constraints into account, and simulation results indicate that using the proposed algorithm achieves near-optimal solutions regardless of the scheduling metric chosen.