This letter proposes a novel fractional frequency reuse (FFR) scheme with hybrid-beam trisector cell (HBTC) architectures that combine narrow-beam trisector cell (NBTC) and wide-beam trisector cell (WBTC) architectures to increase the system performance of cellular mobile networks. In the proposed FFR scheme, the macro base station first divides its macro user equipments (MUEs) into two groups, i.e., inner group (IG) and outer group (OG), based on the signal to interference plus noise ratio (SINR) of MUEs and then assigns subchannels to the MUEs in the IG and OG using the NBTC and WBTC antennas, respectively. Through simulation results, it is shown that the proposed FFR scheme outperforms other FFR schemes in terms of the SINR and capacity of MUEs.

This letter proposes a novel dynamic channel assignment (DCA) scheme to improve the downlink system capacity in heterogeneous networks (HetNets) with fractional frequency reuse (FFR). In the proposed DCA scheme, the macro base station (MBS) finds small-cell base stations (SBSs) that give strong interference to macro user equipments (MUEs) and then dynamically assigns subchannels to the SBSs to serve their small-cell user equipments (SUEs) according to the cross-tier interference information to MUEs. Through simulation results, it is shown that the proposed DCA scheme outperforms other schemes in terms of the total system capacity.