Analytical Study of Interference Mitigation in Heterogeneous Networks Deployed in High-Density Residential Areas in Ibadan

Heterogeneous network deployments combining macrocell base stations with small cells such as femtocells and picocells offer a cost-effective approach to densifying network capacity in high-density residential environments, but introduce complex inter-tier interference that requires analytical characterization for effective mitigation. This study analytically investigates interference mitigation strategies for heterogeneous networks deployed in high-density residential areas in Ibadan, Oyo State, South West Nigeria. Field measurements of path loss, shadow fading statistics, and inter-cell interference power levels were conducted at forty measurement points distributed across three high-density residential neighborhoods in Bodija, Challenge, and Eleyele. The measured channel parameters were used to parameterize a stochastic geometry-based analytical model of the heterogeneous network interference environment. Cell range expansion bias and enhanced inter-cell interference coordination techniques were analytically evaluated using the parameterized model. Results indicate that a cell range expansion bias of 12 dB combined with almost blank subframe ratio of 0.5 achieves the optimal signal-to-interference-noise ratio distribution for the measured Ibadan residential propagation environment, improving average cell-edge throughput by 67% compared to a macrocell-only deployment. The analytical model is validated against additional field measurements not used in parameterization, achieving prediction accuracy within 2.3 dB. This study fills a gap in the heterogeneous network literature by providing locally calibrated interference characterization for West African dense urban residential environments. Keywords: heterogeneous network, interference mitigation, picocell, Ibadan, cell range expansion.