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The 5G Heterogeneous Cellular Networks (HetCNs) must deliver high data rate to cellular subscribers by offloading traffic and also by enhancing indoor and cell-edge coverage. These future indispensable requirements could be significantly persuaded through the proper arrangement and densification of the network serving towers along with the exploitation of millimeter-wave (mmWave) spectrum. Small cells (SCs) that utilize the mmWave high-frequency band and the traditional Macrocells (MCs) towers that could transmit within the pre-existing sub 6 Gigahertz (6 GHz) spectrum are immensely forecasting in attaining an optimum network system capacity as well as minimized interference. Additionally, the SCs lead to be the most appropriate domain in terms of the transmission with an mmWave following its characterized wave factors, which include high path loss, shorter wavelength, and limited propagation distance. Moreover, owing to its narrow beamwidth and high directivity, mmWave covers a higher lane in interference management. The future cellular network embarks with the inclusion of either both fixed and mobile small-cells (mSCs) only or with high-powered MCs. To provide good quality services in highly crowded traffic areas including railway stations, office compounds, and hotspot areas, the network operators are bound to opt for the extensive deployment of fixed and mobile SCs. The mobile SCs that are typically mounted over the vehicles to access the coverage of remote areas seem to be an unsurpassed approach that could not only minimize the communication link between the base station (BS) and user but also aid towards low power signal transmission, thus greatly reducing the overall deployment cost. Currently, the researchers are focusing on adopting stochastic geometry (SG) and Poisson Point Process (PPP) for setting up the network entities spatially. In this regard, the SCs deployment could most suitably allow investigating of the modeled network entities with ease, without hampering the foregoing systems and environments.
Even though data demand in the future cellular network could be accomplished, the upcoming 5th generation cellular standards will also bring some challenges such as frequent interferences and energy losses in the network due to faultless running of different serving towers with sharing of the same cellular spectrum and volatile growths in mobile terminals. Moreover, while setting up of HetCNs, movement of mobile users and mobility of SCs might led to dynamic Inter Cell Interference (ICI) effect that would become an issue of problem for network planners.
In this work authors present a dynamic sleeping mechanism for mitigation of dynamic downlink interferences linked with mobile SCs in a 5G HetCN. The proposed Dynamic Mobile Cell Sleeping Mechanism (DMCSM) allows deployed mSCs to dynamically go into sleep based on the calculated distance of a user from mSCs BS. The work investigates the performance of HetCN with mmWave bands at fSCs and mSCs and pre-existing sub 6 GHz bands inside the MC exposure area. The part of the authors’ previously proposed Cell-User Mobility (CUM) model has been adopted to analyze cell mobility. The paper also provides a clearer comparison of the proposed DMCSM mechanism with the authors’ prior proposed Dynamic Fixed Region Cooperation (DFRC), Dynamic Power Allocation Mechanism (DPAM), and Dynamic Power Allocation based on User Location (DPAUL) ICI mitigation techniques. The spatially distributed users in the network are carried out with the Cox process. The radio propagation in the setup network is considered with both large-scale distance and small-scale channel fading models. In this setup, the part of the authors’ previously proposed CUM model is considered for mobile SCs mobility. The mSCs in the setup network is considered to be mounted on vehicles. The allocation of resource blocks among MC and SCs users are carried out with Round-Robin scheduling.