Hierarchical Cooperation in Heterogeneous Cloud Radio Access Networks

Heterogeneous cloud radio access networks (HCRAN), which combines the benefits of cloud radio access radio networks (C-RAN) and heterogeneous networks (HetNets), is an emerging technology to achieve high data transmission rates in 5G cellular networks. In H-CRAN, to mitigate interference among macro BSs (known as high-power nodes (HPNs)) and remote radio heads (known as low-power nodes (LPNs)), Fractional Frequency Reuse (FFR) is used to enhance spectral efficiency in radio resource. However, FFR may incur inefficient resource utilization in OFDMA wireless networks. To solve this problem, in this paper, we explore how to enhance throughput within one cell based on the architecture of H-CRAN based on cooperative communications among HPN and LPNs. Specifically, we study how to form a cooperative cluster efficiently among LPNs for cross-tier cooperation, and propose a hierarchical cooperation strategy to improve system throughput in H-CRAN. We then show via simulations that the proposed hierarchical cooperation is truly an efficient resource allocation strategy in HCRAN.