Research On Resource Allocation For D2D Multicast Communication In Cellular Network

With the recent popularity of smart terminals, the demand for high-data-rate transmission is growing rapidly, which brings a new challenge for the traditional cellular networks. To reduce the burden of evolved Node B (eNB), device-to-device (D2D) communication has been introduced into cellular networks. Different from the traditional cellular communication, user equipments can communicate directly without the relay of evolved Node B (eNB) by D2D communication. D2D communication has been proved effective in improving the performance of local communication with lots of advantages, such as reducing energy cost, extending the coverage area, improving the performance of user equipments (UEs) at the edge of cells and reducing the transmission delay. However, coexisting with cellular communication, D2D communication may generate interference to the traditional cellular communication. Allocating the resource properly is essential to keep the interference within a reasonable range. Many studies concerning the resource allocation of D2D communication have been carried out in those years. However, there are still some limitations: firstly, the interference between D2D communication and cellular communication is a major concern when allocating resource, while the interference between multi D2D links is ignored. Secondly, most of the work has focused on resource allocation of D2D unicast communication, and there has been very little research on D2D multicast communication. Thirdly, most of the research is carried out in single cell, and there are few researches about D2D communication is carried out in multi-cell.In view of the above limitations of traditional study on resource allocation of D2D communication, we have studied the resource allocation of D2D multicast communication in cellular networks in this paper. D2D multicast communication is applied into several typical wireless communication scenarios. The contributions made in this paper include:1) D2D communication is applied into single frequency networks system. A distance-constrained round-robin resource sharing algorithm for D2D communications in a single frequency network (SFN) system is proposed in this article. The proposed algorithm assumes that D2D user equipments (DUEs) do not share frequency with ellular user equipments (CUEs) in the same SFN, but reuse frequency resources with CUEs in other SFNs and the same frequency resource can be reused as the distances between DUEs in one SFN are larger than the reuse safe distance. The simulation results show that the proposed algorithm can utilize the frequency resources better, which greatly improves the system performance.2) This study considers a scenario of D2D multicast communication in a single frequency network (SFN) system and investigates the frequency resource allocation problem. Firstly, we propose that DUEs do not share frequency with CUEs in the same SFN, but reuse frequency with CUEs in other SFNs, by which the interference between D2D and cellular communications can be avoided. Then, under the principle that two nearest D2D multicast groups cannot reuse the same frequency, the study develops a distance-based fair frequency resource allocation (DFRA) algorithm. The DFRA algorithm ensures control of the interference within a reasonable range and fairly allocate the available frequency resources to the D2D multicast groups. Numerical simulation results show that the proposed resource allocation algorithm is effective in improving the data rate and reducing the outage probability for D2D communications.3) A hierarchical resource allocation scheme for D2D communication in small cell network system (SNets) is proposed in this article. We divided the optimal problem into three sub-problems, which includes D2D communication groups’ formation, sub-channels demands estimation, and resource allocation. The main advantage of the proposed hierarchical scheme is decomposing a complex optimization problem into several smaller problems with smaller sets of optimization variables. To make better use of the frequency resource while satisfying the data rate demand of each D2D receiver, a distance-based resource allocation algorithm is proposed to allocate the sub-channels to D2D communication groups. The proposed scheme ensures that the system select the best allocation order and allocate the available sub-channels to D2D communication groups successfully. The simulation results demonstrate that our proposed hierarchical scheme not only improves the spectral efficiency of D2D communication greatly, but also decreases the outage probability of the D2D links.4) We study the power control of D2D multicast communication underlying cellular network. To improve the overall throughput of D2D and cellular communication, particle swarm optimization (PSO) algorithm based power allocation schemes are proposed under two scenarios. Firstly, we introduce a distributed controlled D2D multicast group formation procedure. And then, the system model of both D2D communication reuse the same frequency with one cellular user equipment (CUE) and with multi-CUEs is introduced. Under these two scenarios, the power allocation problems are transformed to constrained optimization problems. Particle swarm optimization (PSO) algorithm is applied to get the solutions for optimization problems. Additionally, to get a compromise between fairness and the overall throughput of system, a new objective function with fairness factor is designed in the second scenario. Simulation results show that the proposed schemes significantly improve the throughput performance of system and guarantee the quality of both D2D and cellular communication.