Cooperative Optimization for OFDMA Resource Allocation in Multi-RRH Millimeter-Wave CRAN

Cloud radio access networks (CRAN) has become an excellent network architecture in the fifth-generation wireless communication systems, which can highly increase the capacity and coverage compared with conventional networks. However, in order to provide the best services, appropriate resource management must be applied. This article considers transmission scheduling of downlink transmission in an OFDMA-based Millimeter-Wave (mmWave) CRAN, where data transmission on each subcarrier (SC) can be used by different remote radio heads (RRHs). A joint optimization problem of user association, SC allocation, RRH allocation and power allocation is formulated to maximize the weighted sum-rate. To efficiently solve this joint optimization problem, we first divide it into two subproblems: 1) joint optimization allocation of user, RRH and SC for fixed power allocation, 2) power allocation for fixed allocation of user, RRH and SC. We propose a novel algorithm to tackle the joint optimization problem by solving these two subproblems alternately. The simulated results indicate that the proposed multi-RRH cooperative algorithm can improve the transmission performance in terms of the weighted-sum rate and power efficiency. Moreover, the proposed algorithm has low computational complexity, which ensures the feasibility of the proposed scheduling algorithm in practical systems.