仿真实验二：MIMO系统信道容量仿真比较

1、仿真实验二： MIMO 系统信道容量仿真比较一、实验目的：MIMO 多天线系统所提供的空间复用增益和空间分集增益可以极大地提高 无线链路的容量和质量。现有的研究成果己经表明， MIMO 所能达到的极高的频 谱效率是目前任何一种无线技术所不及的， 因此它被认为是未来第四代移动通信 系统的备选关键技术之一。 根据信道的输入输出情况， 使用多天线技术的通信系 统可以分为单输入多输出 SIMO( Single-Input Multiple-Output )系统、多输入单 输出 MISO (Multiple-1 nput Single-Output )系统，以及多输入多输出 MIMO( Multiple

2、-Input Multiple-Output )系统三种类型。本实验将根据香农定理和信道 模型，推导出 MIMO 信道容量公式，并且进行仿真分析。二、实验原理： 根据不同的传输信道类型，可以在无线系统中使用相应的分集方式。目前， 主要的分集方式包括时间分集(不同的时隙和信道编码) 、频率分集(不同的信 道、扩频和OFDM )以及空间分集等。多天线系统利用的就是空间方式，而MIMO 作为典型的多天线系统， 可以明显提高传输速率。 而在实际的无线系统中， 可以 根据实际情况使用一种或者多种分集方式。三、试验程序：clear all; close all; clc;M = 1000;Nt = 1,2

3、,4 8;Nr= 1,2,4,8; s=b-o,b-*,b-square,b-hexagram;SNR = 0:2:16; %dBfigure(1);title(compare of a MIMO system and a SISO system) xlabel(SNR dB);ylabel(Capacity);grid onhold on;for n = 1:length(Nt),t = Nt(n);r = Nr(n);for m = 1:M,H = raylrnd(1,r,t);for l = 1:length(SNR),rou = 10A(SNR(l)/10);% Find the ca

4、pacity while CSIT unknown CU(m,l) = log2(real(det(eye(r)+rou*H*H/t);endendC_unknown(:,n) = mean(CU)for l = 1:length(SNR),cdf_u,co_u = hist(CU(:,l),100);cdf_u = cumsum(cdf_u);idx_ten_percent = find(abs(cdf_u-100)=min(abs(cdf_u-100);C_unknown_outage(l,n) = co_u(idx_ten_percent(1) endfigure(1);linetype

5、 = s(n);plot(SNR,C_unknown(:,n),deal(linetype:);legend(Mt=1,Mt=2,Mt=4,Mt=8) end 四、试验参数选择：1. 输入天线的数目；2. 输出天线数目；3. 信噪比。五、实验结果及分析： 结果：C_unknown =1.31551.69862.13562.62033.14573.70444.28964.89565.5175C_unknown_outage =0.20420.32520.47260.70281.03571.35251.78552.35462.9015C_unknown =1.3155 2.37851.6986 3

6、.00382.1356 3.70402.62034.47403.14575.30943.70446.20624.28967.16044.89568.16795.51759.2242unknown_outage =0.20421.45660.32521.91980.47262.47380.70283.11621.03573.75641.35254.45101.78555.18992.35465.96532.90156.8837unknown=1.31552.37854.02131.69863.00385.05272.13563.70406.23802.62034.47407.58063.1457

7、5.30949.07943.70446.206210.72834.28967.160412.51724.89568.167914.43375.51759.224216.4641C_unknown_outage =0.20421.45663.23820.32521.91984.09600.47262.47385.06940.70283.11626.18051.03573.75647.49341.35254.45108.83011.78555.189910.38272.35465.965312.08392.90156.883713.9220unknown =1.31552.37854.02136.

8、65071.69863.00385.05278.44392.13563.70406.238010.57892.62034.47407.580613.07143.14575.30949.079415.92083.70446.206210.728319.11174.28967.160412.517222.61814.89568.167914.433726.40745.51759.224216.464130.4446C_unknown_outage =0.20421.45663.23825.94340.32521.91984.09607.55420.47262.47385.06949.47400.7

9、0283.11626.180511.72511.03573.75647.493414.31701.35254.45108.830117.24481.78555.189910.382720.49292.35465.965312.083924.10382.90156.883713.922027.8940unknown =1.31552.37854.02136.65071.69863.00385.05278.44392.13563.70406.238010.57892.62034.47407.580613.07143.14575.30949.079415.92083.70446.206210.728319.11174.28967.160412.517222.61814.89568.167914.433726.40745.51759.224216.464130.444635compare of a MIMO system and a SISO system30WTrcaBar:iEl0246810121416SNR dB5 0 52 2