DEVELOPMENT OF AN ENHANCED ACTIVE POWER CONTROL TECHNIQUE FOR INTERFERENCE MITIGATION IN MACRO FEMTO CELLULAR NETWORKS

Abstract

Femtocells are overlayed on existing Macrocells to form Macro-Femto heterogeneous network (HetNet), to reduce cost of mounting expensive macrocell nodes, improve cellular network capacity and throughput performance. However, HetNet has a major problem of cross-tier and co-tier interference, which hinders its optimal performance, especially when the network capacity expands. With emergence of 5G technologies, interference would become more consequential. Therefore, curbing the effect of this interference is indispensable to sustain larger and efficient HetNet. In this work power control technique was explored to reduce the impact of interference in both Downlink and Uplink scenarios of 5G non-stand-alone (NSA) architecture of Macro-Femto HetNet. An enhanced active power control (EAPC) technique, was developed by hybridizing extended attenuation factor path loss model, Active Power Control (APC), and Power Control 1 (PC1) techniques. Attenuation factor model was extended by adding floor factor to capture both floor attenuation and wall factor, and used same in computing femtocell path loss. The EAPC technique also made use of a different step power value of 0.5 dB for adjusting it’s transmit power in order to maximize power and reduce interference. The hybridization when compared with APC and PC1 respectively yielded: 65% and 37% higher Home User Equipment (HUE) throughput; 37% and 21% higher Macro User Equipment (MUE) throughput; 41% and 63% higher throughput of femtocell node (Hen-gNB); 69% and 25% higher throughput of macrocell node (en gNB). EAPC average power consumption compared to APC and PC1 respectively saved: 65% and 40% HUE battery energy; 38% and 42% MUE battery energy; 54% and 22% Hen-gNB energy. EAPC saved 21% en-gNB energy when compared to APC, but was limited by 8% when compared with PC1.