Analyzing Coverage Probability in Full-Duplex Two-Tier Networks with Offloading and Resource Partitioning

Full-duplex (FD) communication improves spectral efficiency by allowing simultaneous transmission and reception on the same frequency band. This paper analyzes a two-tier network consisting of macrocells and picocells, where base stations (BSs) operate in FD mode while users operate in half-duplex (HD) mode. However, interference remains a major challenge in these systems, significantly impacting coverage probability. To enhance network performance, we incorporate user offloading and resource partitioning. Offloading redistributes users from macrocells to picocells to balance the network load. However, offloaded users often experience lower SINR compared to those connected to macrocells. Resource partitioning is applied to mitigate this SINR degradation and reduce interference. This method allocates a fraction of time or frequency resources where macrocells remain inactive, allowing picocells to serve users with less interference. We derive analytical expressions for the downlink coverage probability, considering the effects of offloading, resource partitioning, and key network parameters. Our results indicate that load balancing by itself is insufficient; however, when resource partitioning is combined with offloading, DL coverage probability is significantly improved.