Improving Macrocell-Small Cell Coexistence Through Adaptive Interference Draining

Abstract

Abstract-The deployment of underlay small base stations (SBSs) is expected to significantly boost the spectrum efficiency and the coverage of next-generation cellular networks. However, the coexistence of SBSs underlaid to a macro-cellular network faces important challenges, notably in terms of spectrum sharing and interference management. In this paper, we propose a novel game-theoretic model that enables the SBSs to optimize their transmission rates by making decisions on the resource occupation jointly in the frequency and spatial domains. This procedure, known as interference draining, is performed among cooperative SBSs and allows to drastically reduce the interference experienced by both macro-and small cell users. At the macrocell side, we consider a modified waterfilling policy for the power allocation that allows each macrocell user (MUE) to focus the transmissions on the degrees of freedom over which the MUE experiences the best channel and interference conditions. This approach not only represents an effective way to decrease the received interference at the MUEs but also grants the SBS tier additional transmission opportunities and allows for a more agile interference management. Simulation results show that the proposed approach yields significant gains at both macrocell and small cell tiers, in terms of average achievable rate per user, reaching up to 37%, relative to the non-cooperative case, for a network with 150 MUEs and 200 SBSs.

Secrecy Transmit Beamforming for Heterogeneous Networks

“…Inspired by this insight, the interference should be utilized, rather than avoided, to improve the secrecy rate in HetNet using techniques such as proper spectrum allocation and cooperative beamforming. To elaborate a little further, motivated by the inter-cell interference coordination techniques [31]- [35], spectrum allocation can be rearranged dynamically in conjunction with various levels of cooperation between the network nodes, such as the MBS and FBSs, to generate the desired co-channel interference (CCI) to the eavesdropper. As a result, judicious cooperative beamforming schemes may be designed to cope with CCI for the sake of improving the secrecy rate performance in HetNet.…”

A Stochastic Game-Theoretic Approach for Interference Mitigation in Small Cell Networks

“…The number of available channels is set to be 4, and the bandwidth of each channel is 200 KHz. The radius of the macrocell and femtocell is 650 m and 25 m, respectively [5]. The transmitting power of the macrocell and femtocell is 10 W and 1 W, respectively.…”

“…The main contributions of this letter are threefold: i) we formulate a stochastic game to investigate the distributed and interactive channel selection for the dynamic small cells networks; ii) the formulated game is proved to be an exact potential game, in which the Nash equilibrium (NE) solution minimizes the expected network interference, either globally or locally; and iii) we design a fully distributed, no-regret learning algorithm to find the NE in dynamic environment. It is worth noting that most existing works perform centralized interference management which creates enormous signaling overhead [2], [5]. Besides, the existing distributed solutions using game theory mainly focus on the static network [1], [7], [8], and pay little attention to fully distributed scenarios without information exchange [7], [8].…”

Space Alignment Based on Regularized Inversion Precoding in Cognitive Transmission

“…We assume P and R only acquire the perfect H RP of the primary system, and S can get the whole perfect CSIs, H RS and H RP . Actually, the CSIs can be acquired by the channel reciprocity in Time-Division Duplexing (TDD) communications [11] and CSI exchange techniques in Frequency-Division Duplexing (FDD) communications [12].…”