蜂窝小区同频干扰的Matlab仿真Word下载.docx

1、is characterized by the interference at a specific position, e.g. at the fringe of a cell or at the center of a cell. Because of the random position of a mobile subscriber （MS） and other random factors, the co-channel interference is also a random variable. As known, interference cancelation techniq

2、ue can greatly improve the system capacity in the cellular mobile system, especially in the CDMA systems. It is helpful to know the distribution of the interference when adopting interference cancelation techniques. Therefore, our experiment devotes to find the distribution of the co-channel interfe

3、rence in the cellular mobile system with cluster sizeN. Let us assume the cell radius R, each MS could appear at any position in the cell with equal probability. The average received power Pr at a distance d from transmitter is𝑝 = 𝑝 （ 𝑑 ） - 𝑛approximated as 𝑟0

4、 𝑑, where P0 is the power received at a small distance d0 fromthe transmitter and n is the path loss exponent. The experiment requirements are the follows.DESCRIPTION OF THE EXPERIMENTS1. Write a program to calculate the signal interference ratio （SIR） in the forward link, and repeats it by

5、randomly changing the position of the MS. After a number of simulations, use the simulated results to draw the histogram of the SIR （S=I）. Try to obtain histograms with different path loss exponent n and cluster size N. Conclude your results.The co-channel interference in the forward link can be cha

6、racterized in figure 1. A MS will be interfered by the co-channel base station. In our simulation, we consider the 18 co-channel cell, including 6 cells in the first loop and 12 cells in the second, no matter what the cluster size N is.Figure 1 forward link co-channel interference（1） Firstly, we sho

7、uld randomly choose the position of the MS in the cell. Since the cell is hexagon which is hard to handle we cut and paste it into a square. As we can see in figure 2, the center of the coordination is the center of the cell. The square we choose is ABCD. We then randomly choose a pair of x and y as

8、 the coordinate of MS. If MS locates in triangle 1 we cut and paste it to triangle 3 and if it locates in triangle 2 we move it to triangle 4.We assume the range of the base station is 0.1 as radius of cluster is 1. For the MS who located within this area, we change its distance to be 0.1 as it is t

9、oo close to the base staion.Figure 2 randomly choose the position of MS in a cellMatlab code:RandPOS.m%*% This function is to get the randomly laction of the MS with m times.% z is a m*1 matrix with coodinate value x,y%* function z = RandPOS（m）%* get random value of x,y within a square *% x = 1.5*ra

10、nd（m,1）-1;y = sqrt（3）*rand（m,1）-0.5*sqrt（3）;%* use for loop to cut the square into a hexagon *% for k=1:mif x（k）-1 & x（k）（1+x（k）*sqrt（3） x（k）=x（k）+1.5;y（k）=y（k）-sqrt（3）/2;elseif x（k） y（k）-（1+x（k）*sqrt（3） x（k）=x（k）+1.5;y（k）=y（k）+sqrt（3）/2;end%* if the MS is too nearly to the base station*% if sqrt（x（

11、k）2+y（k）2）0.1x（k）=0.1;y（k）=0;z=x+j*y;.（2） Secondly, we should calculate the coordinate of co-channel base station. As we know the cluster size N we can calculate the （i, j） pair by the formula𝑁 = 𝑖2 + 𝑖 * 𝑗 + 𝑗2ClusterN.m%*% This function is to find i&j corres

12、pond to a given N% as N = i2+j2+ij% ii and jj is the result of i,j%* function ii,jj = ClusterN（N）% the largest number of i and j is sqrt（N）for a = 0:sqrt（N）for b = 0:if a2+b2+a*b = N ii = a;jj = b;end;%end if end; %for jj（3） Taking N=7 as example, we can calculate the coordinate by referring to figure 3. According to the value of I j pair and angles in the figure we can get the coordinate of the firstloopbytheformula: 𝑗 𝑝𝑖 + 𝑗𝑝𝑗𝑙𝑜𝑐𝑎𝑡𝑛（𝑘） = 3 （𝑖 𝑒63 （𝑘 1）