Design and Simulation of a 4G LTE Small Cell Base Station for Indoor Coverage Improvement in Nigerian Office Buildings

Indoor 4G LTE coverage in multi-floor commercial office buildings in Nigerian urban centres is frequently inadequate, resulting in dropped calls, slow data speeds, and reduced workforce productivity. This project designed and simulated a 4G LTE small cell (femtocell) base station configuration for improving indoor coverage in a representative six-floor office building in Abuja, Federal Capital Territory. The design was developed in MATLAB's LTE System Toolbox, which was used to model the radio propagation environment using a 3GPP indoor office channel model. Antenna placement optimisation was conducted using a genetic algorithm to minimise coverage dead zones across all six floors. The simulated femtocell transmit power was set at 100 mW in accordance with regulatory limits, and the operating frequency was 2600 MHz (Band 38) to align with MTN Nigeria's current LTE deployment band. Coverage analysis showed that the optimised three-femtocell configuration achieved greater than minus 85 dBm reference signal received power across 96.4 percent of the building floor area. Compared to a single macro-cell-only scenario, indoor data throughput improved by an estimated 340 percent using the small cell overlay. Interference between the macro cell and femtocells was managed through HeNB-based interference coordination. The study recommends physical prototyping using a commercially available femtocell gateway and conducting real-world propagation measurements to validate the simulation model under Nigerian building construction material conditions.

Keywords: LTE small cell, femtocell, indoor coverage, MATLAB simulation, 4G network design