# An Improved Anti-Interference Precoding of Large-Scale Fading System Based on Channel Inversion
## 5 Simulation  
The performance of anti-interference precoding was analyzed in terms of the communication transmission rate. The simulation graph represents the cumulative distribution function (CDF), which can reflect the received signal-to-interference and noise ratio and the information transmission throughput rate [15]. In the simulation, the performance of communication transmission rate of improved and conventional precoding schemes, which includes ZF-LSFP, AZF-LSFP, O-LSFP, AO-LSFP and MMSE-AO-LSFP, is compared under different base antenna numbers. The simulation model was based on Section 2 channel model setting. We model the large-scale fading coefficient \(\beta_{j}^{kl}\) as log-normal distribution based on the Urban Macro model that followed the 3 GPP (3 rd Generation Partnership Project) standard. Cell base stations and user settings in Figure 2: the number of cells contained in a single cell group was L = 19, the number of users contained in a single cell was K = 10, and the number of cell base station antennas was M. The cell was randomly distributed to ten mobile users. The cell radius was r = 1 km. The cell base station was set in the center. The mobile user was randomly located in a circular area having the base station as a center, a radius of 62.5 m.  
The cell numbers in the area group were set to L\({}_{1}\), 1 = 1, \(\cdots\), 19. Each cell center point was set with two-dimensional coordinates and the L\({}_{1}\) coordinate is L\({}_{1}\)(0,0). According to the cell radius, the coordinates of all cell center points L\({}_{1}\)(m\({}_{l}\), n\({}_{l}\)) can be generated. The distribution map of users of a single cell is presented in Figure 3 left, where each dot represents a user. The user distribution range was set in the simulation, and the generated points were randomly distributed. Randomly selecting a hexagonal cell, and the center point is the base station position. The positions of 10 users in this cell are randomly generated. The user positions are evenly distributed in the cell. We eliminate the extreme case that all users are distributed at the cell edge. A random distribution diagram of a total of 190 users grouped into 19 cells within the cellular network to which they belonged is presented in Figure 3 right. The relative distance between a user and 19 base stations was obtained using the same principle as in spatial channel model for multiple input multiple output (MIMO) simulations of Technical specification group radio access network. Figure 3: Distribution of users in a single cell and Relative distribution of all users in the area. Figure 2: A cellular network composed of 19 hexagonal cells. There are 19 communities in the cellular network, with a total of \(19\times 10\) users. The location of 190 users is randomly generated in a hexagonal cell with the center point coordinate of (x,y), and a group of 10 users Substitute the coordinates of 19 center points \(\mathrm{L_{1}(m_{l},n_{l}),1=1,\cdots,19}\) in turn, and obtain the coordinate of all users in each cell. Then, we can calculate the distance \(d_{j}^{kl}\) according to coordinates of the \(j\)-th BS and the \(k\)-th user in the \(l\)-th cell. Considering the movement of end users, it was assumed that users move freely in the cell to which they belong, but irrespective of the extreme case where all users move to the edge of the cell. The distribution of users in the cell is still roughly evenly distributed. The positions of 190 users were randomly generated in the hexagonal cell with the center point coordinate of (x,y) for many times. The user position distribution changes as shown in the point in Figure 4, which simulates the free movement of users in each cell. According to the set system model, a large-scale fading factor \(\beta_{j}^{kl}\) was obtained using the 3 GPP urban macro model, which is given by (2). Other simulation settings: the transmit powers of the BS and users were \(\rho_{r}\) = 23 dBm and \(\rho_{f}\) = 23 dBm, respectively.