Impact of Frequency Reuse and Flexible Cell Association on the Performance of Dense Heterogeneous Cellular Networks Using Dual-Slope Path Loss Model

Abstract

Densifying low-power/small base stations (SBSs) in support of overlaid macro BSs (MBS) is getting significant consideration as a viable solution for meeting the rapidly increasing capacity demands of emerging wireless networks. Given the disparity in transmit power of BS tiers, load balancing strategies have achieved paramount importance as they ensure balance of user access load amongst BS tiers and assist in availing maximum potential of multi-tier networks. Moreover, it is also essential to utilize efficient interference management schemes to account for the excessively increasing interference in the deployed networks. There is a plethora of literature available on the analysis of dense multi-tier networks that undertake various load balancing and interference management mechanisms but they are strictly limited to single slope (SS) path loss model (PLM). Furthermore, it is also well-known in literature that SS-PLM leads to inaccuracies in estimating the performance of dense networks owing to the simplistic approach of estimating the path loss. To overcome the limitations of SS-PLM, in our work, we have employed DS-PLM to study and analyze the performance of a two-tier dense cellular network that permits flexible user association using SBS biasing in conjunction with a simple frequency reuse mechanism. A comparison of SS-PLM with DS-PLM is performed for tier association probability and coverage probability, which shows that there is significant difference in the estimated overall network performance of our proposed scheme, as compared to SS-PLM. The results clearly signify the benefits of utilizing both load balancing and interference management mechanisms under DS-PLM, and give critical design insights for finding optimal parametric values in cellular planning. INDEX TERMS Coverage probability, dual-slope path loss model, frequency reuse, heterogeneous cellular networks, load balancing, stochastic geometry.

Service Quality of the Urban Microcellular Scenario in the Sub-6 GHz Frequency Bands

“…In HetNets, SS-PLMs also fail to estimate losses since the laws of physics applied to urban environments where there is a reflection on the ground, which shows that a dual slope (DS) behavior is observed. This behavior is more evident in small cell networks for the sub-6 GHz bands [48]. To overcome the above limitations of the SS-PLM, the DS-PLM can be used since they can appropriately describe the channel propagation behavior in the UMi scenario.…”

“…The authors from [25], [39], [48], [49] compare mathematical modeling approaches between SS-PLMs and DS-PLMs. They show that the use of DS-PLMs implies higher supported throughput for the longest cell radii in small-cell outdoor environments.…”

“…They show that the use of DS-PLMs implies higher supported throughput for the longest cell radii in small-cell outdoor environments. The authors from [4], [11], [48] highlight that DS-PLMs present more accurate performance results for coverage probability and user association than SS-PLMs. In fact, DS-PLMs are gaining importance in the characterization of propagation environments of successive generations of mobile communications systems in earlier 3GPP releases [30] and in 5G NR scenarios [31], [50].…”