Optimal Deployment of Assisting Cells for Multimedia Push in Single Frequency Network

Long term evolution (LTE) systems are equipped deliberately with the multimedia broadcast/multicast service over a single frequency network (MBSFN) to save transmitting resources. With the usage of assisting cells in MBSFN transmission, there is a significant effect on raising spectral efficiency (SE), and energy efficiency (EE) may be promoted synchronously. In this paper, we propose a circle model to approximate the SE in a hexagonal user equipment (UE) drop area for analysis. Based on the model, the optimal allocating scheme of assisting cells with a certain number is presented. Both in theory and simulation, the SE is changed non-linearly while increasing the number of assisting cells under the optimal allocating scheme. Evaluated by EE, it is proved that the optimal deployment of assisting cells is shown as a number of assisting rings, and the optimal number of assisting rings is related to the size of hexagonal UE drop area. Compared with nonuse of assisting cells, there is a significant improvement on EE as the optimal deployment configured, and the EE gains with different sizes of hexagonal UE drop areas are shown in simulation.