Research Of Resource Allocation And Application For Device-to-Device Communication In Cellular Networks

With the development of the cellular wireless network, the demand for localized data between cellular users is increasingly growing. However, the traditional cellular wireless network is unable to satisfy the users’ local data exchange requirements on account of its characteristic that cellular network does not support direct communications between cellular users. In this context, Device-to-Device(D2D) communication, as a lately emerging technology which allows direct communications between the cellular devices without a relay of the base station, is added to the traditional cellular wireless network to reinforce and complement it, and has been widely accepted by academia and industry.In this thesis, aiming at D2D-enabled wireless cellular network, some research of resource allocation for D2 D communication in cellular networks are conducted, and some preliminary work about D2 D communication applied to cellular multicast are presented by introducing cellular wireless multicast services.With regard to resource allocation for D2 D communication in cellular networks, it is diveded into two modes from the perspective of resource block(RB) and the two modes are discussed separately. Nevertheless, we still manage to present a unified resource allocation implementation framework which effectively ensures the successful execution of resource allocation process.In the overlay mode, reuse of RBs occurs only between D2 D links. The spatial multiplexing levels of the RBs occupied by D2 D links are maximized in order to reduce the cellular resources allocated to them. By analysing the case of simultaneous transmissions of D2 D links, the conditions for RB reuse are proposed upon which an optimization problem is established, and the allocation of RBs between D2 D communicaton and traditional cellular communication is realized by solving the optimization problem.The resource allocation of underlay mode is still supervised by the unified resource allocation framework. Since that B2 D links can access the RBs allocated previously to D2 D links, it is possible to enhance the spatial multiplexing levels of RBs and a more difficult optimization problem needs to be considered at the same time. In the underlay mode, the target is setted as maximizing the spatial multiplexing levels and then another optimization problem can be formulated which contains a lot more variables according to the max-min fair principle. We finally succeed in achieving the near optimal RB allocation result by introducing the column generation method.Cellular multicast service, as an effective means of content distribution in wireless network, can be used in a wide range of applications. However, because of the few users in worst channel conditions and their available maximum rate limitation for reliable reception of multicast data, there is always a bottleneck problem in terms of throughput accompanying the primary cellular multicast service. With additional D2 D communications in cellular networks, reliable multicast data transmission can be guaranteed by the localized D2 D communication and the data exchange among the recipients in the multicast group. During this process, members of the multicast group, on one hand, are cellular users who receive multicast data from base station. On the other hand, they also act as relay stations to forward multicast data through direct communications between devices. The base station could ignore several recipients in bad channel conditions and transmits data at a relatively high rate. In this case, part of the recipients who have successfully received the data forward it, according to certain strategies, to those unreceived. It is important to note that in D2 D relay cooperatived cellular multicast, the selection and determination of relay users will directly affect the amount of cellular resources consumed by D2 D communications. Based on the consideration of resource utilization efficiency, some preliminary research work about the selection strategy of D2 D relays in cellular multicast is presented.