Modeling, Analysis and Design for Carrier Aggregation in Heterogeneous Cellular Networks

Carrier aggregation (CA) and heterogeneous base stations (HetNets) and are two distinct features of nextgeneration cellular networks. CA increases transmission bandwidth by aggregating multiple component carriers on the physical layer, while small cells in HetNets are vital for data off-loading and can significantly improve area spectral efficiency compared to using just macrocells. In this paper, we propose a tractable multi-band multi-tier model for CA in HetNets, where base station positions in each tier follow an independent Poisson point process (PPP). Our model incorporates an appropriate notion of load. For a typical HetNet consisting of two tiers, macro and small cells, and two bands, 800MHz and 2.5GHz band, we find that small biasing factor (less than 10dB) yields little gain and the maximum biasing gain is about 25% to 40%, attained at large biasing factors. Our model also characterizes the impact of band deployment. For the typical HetNet described, our study suggests that the 800MHz band be deployed both in macro and small cells to ensure coverage and balance network load. Our study also indicates that deploying the 800MHz band and 2.5GHz band in both the macro and small cells is optimal.