Interference Management In Device-to-Device Communication

In recent years, we need higher spectrum efficiency to meet the increasing requirements for services and data transmission due to the explosive growth of mobile users. Now, an end-to-end direct communication technology which can improve system spectrum efficiency effectively----Device-to-Device (D2D) communication technology has attracted tremendous attention in both academia and industry. In this paper, we investigate the scenario where D2D users reusing cellular users' resources,therefore there must be interference between D2D users and cellular users. Using interference management technology to address the interference problem of D2D communication is the key point of this paper. The main contribution of this paper has the following three aspects:1. We use interference alignment (IA) to address the interference problem of multiple D2D pairs reusing resources with multiple cellular users in multi-cell networks. First, we propose a novel cell division pattern based on conventional fractional frequency reuse (FFR) to create user clusters, and divide the multi-cell networks into intra-cell clusters and inter-cell clusters. There will be no interference between adjacent clusters with reasonable resource allocation. The interference inside each cluster will be addressed by IA. Based on the feasibility of IA, we give the feasible configuration, the corresponding precoding, decoding matrices and the capacity calculation formula of both intra-cell clusters and inter-cell clusters. The simulation results show that the distinctive capability of IA in term of eliminating interference and improving the system performance. Additionally, the optimal frequency reuse partitioning proportion is 0.7 when the whole system obtains the highest spectrum efficiency.2. We use IA to address the interference problem of two D2D pairs reusing resources with two cellular users in single cell network,and use maximum chordal distance optimization algorithm, precoding optimization algorithm based on eigen-channel and the optimal capacity optimization algorithm to study the influence of different precoding optimization algorithm in system capacity. Compared with the conventional IA, the simulation results show that the above algorithms can obtain higher system capacity, and the optimal capacity optimization algorithm can obtain the highest system capacity.3. We use topological interference management to address the interference problem of a hybrid interference network which consists of one D2D pair and two cellular users. Topological interference management refers to the Degrees of Freedom(DoF) analysis of an interference network with no channel state information at the transmitters (CSIT) beyond the network topology information. In this paper,we give the detailed derivation process of DoF lower bound and DoF upper bound. The result shows that the lower bound matches the upper bound and therefore we obtain the closed-form solution DoF of the hybrid interference network. Compared with the full connectivity state, we derive 1/2 DoF gain from the benefits of topological interference management with alternating connectivity in the hybrid interference network.