Uplink Interference Management for Hetnets Stressed by Clustered Wide-Band Jammers

In heterogeneous cellular networks (HetNets), small base stations (SBSs) are overlaid in the coverage region of a macro base station (MBS) to improve coverage and spectral efficiency. However, the performance of HetNets is significantly degraded by inter-cell interference (ICI) due to aggressive frequency reuse and multi-tier deployment. Besides ICI, the uplink (UL) communications of MBS edge-users (M-EUs) are prone to jammers' interference (JI) due to wide-band jammers (WBJs). With sufficient knowledge of network parameters, such as frequency bands and transmit powers, WBJs inject JI in the UL communications band to affect legitimate communications by degrading UL signal-to-interference ratio (SIR). Such distributed denial-of-service (DDoS) attacks normally target organizations, shopping malls, or public gatherings by clustering around them. As a countermeasure, we use decoupled association (DeCA) for the M-EUs, as opposed to the coupled association (CA), to improve UL SIR. Additionally, we use proactive interference management scheme, known as reverse frequency allocation (RFA), along with DeCA to resist both ICI and JI. The results show that WBJs cluster effectively degrades the legitimate UL communications of the target. The results also demonstrate that the network performance degrades significantly by increasing jammers' density and transmit power. Furthermore, DeCA with RFA leads to improved network performance due to effective ICI and JI mitigation.