# Interference Challenges and Management in B5G Network Design: A Comprehensive Review
## 4 Interference in B5G Networks
### Heterogeneous Networks
#### 4.1.4 Related Works in HetNet
Similarly, for the varying power transmission, the proposed technique achieved 5.85% and 6.292% better SE and sum rates, respectively. Nonetheless, the dynamic heterogeneous environment to measure and address the influence of time events and interference that have a large impact on the power consumption for the proposed technique was not considered in this technique. * Cross-tier Interference Solutions  
In [75], the authors investigate the interference management in two-tier uplink and downlink HetNet scenarios where the uniform and non-uniform SBS deployment were considered. A soft frequency reuse (SFR) scheme combined with a power control factor was proposed. The proposed scheme alleviates the significant interference received from MBS because of offloaded users with optimum resource utilization. The SBSs were distributed uniformly using the PPP, while Rayleigh fading with standard path loss model and Addition Wight Gaussian Noise (AWGN) was considered. Numerical results stated that the suggested model achieves a greater probability of coverage because of the reduced interference and efficient use of SBS resources. Moreover, the results stated that the optimum radius for MBS's interior coverage region is around 70% of the radius for MBS's edge coverage region. In addition, the coverage area was improved when the SINR value decreased because of the increase in the number of users. However, it was found that when the MBS and SBS densities increase, the interference also increases, which minimizes the probability of coverage of the proposed system. In [76], a new SFR algorithm was proposed to mitigate interference and maximize the network's throughput. The proposed scheme involves switching on/off SCs based on their interference contribution rate (ICR) values. SFR divides each SC into two zones: the center zone and the edge zone. The proposed scheme beats the previous switching on/off systems in terms of total system data rate, normalized traffic losses, power efficiency, and outage probability. Moreover, the results revealed that both irregular and circular forms have satisfactory performance in the center zone. Thus, the circular center zone was recommended for use with omnidirectional antennas due to the ease of deployment. However, the optimum proportion relative to the SC radius is 50%. Nevertheless, the end-to-end delay which affects the reliability of the proposed system is neglected in this study. In [77], a multi-level SFR scheme for downlink HetNet was proposed to enhance the cell throughput and area spectral efficiency (ASE) while reducing the probability of outage due to ICI. In the proposed scheme, a mutually exclusive spectrum (MES) is associated with MC, SC, and edge users among different cells in the reuse system. The simulation results stated that the proposed scheme achieves significant improvement in cell throughput by 3.5-fold, ASE, and the probability of outage reduces by 5-fold compared with the traditional SFR scheme. Yet, the power allocation strategy which affects the average power efficiency of the proposed scheme was not considered in this work. In [78], decoupling association (DeCA) with reverse frequency allocation (RFA) in non-uniform HetNets (NUHs) based on the Poisson hole Process (PHP) for small base station deployment was proposed. The suggested technique aims to enhance uplink coverage due to improving the uplink signal-to-interference ratio (SIR) by mitigating uplink interference (UI), macro base station interference (MBSI), and ICI. The simulation results stated that the DeCA outperforms CA in terms of uplink coverage performance. In addition, the proposed system improvement was 76% in uplink coverage for SIR threshold values greater than 0 dB. Moreover, the high-value FPL compensation factor results in better coverage performance for the proposed system. However, the authors did not consider the user's mobility, which has a massive effect on the power consumption of the proposed system.