matlab仿真OFDM

xiangcheng139

1. %%%%%%%%%%%  Developed for 16 QAM %%%%%%%%%%%%%%
   
2. clear all
   
3. close all
   
4. t0=clock;
   
5. %%%%%%%  INPUT PARAMETERS %%%%%%%%%%%
   
6. %%%%%  N=, Number of FFT Points
   
7. N=1024;
   
8. %%%%% M=, Number of OFDM Sub Carriers
   
9. M=512;
   
10. %%%%% L=, Number of Symbols
    
11. L=10;
    
12. MMMa=16;%%%% Modulation Method %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% QPSK 16QAM
    
13. MMM1a=log2(MMMa);
    
14. %%%%% Tg=, Gurd Interval Ratio %%%%%%%%
    
15. Tg=0.1;
    
16. W=10;%%% Bandwidth(MHz)
    
17. DFF=W/M;
    
18. %%%%%% ts=, Effective Sumbol Duration (Micro Sec) %%%%%%%
    
19. ts=M/W;
    
20. %%%%%% D=, Gurd Interval Duration (Micro Sec) %%%%%%%
    
21. D=ts*Tg;
    
22. %%%%%% Ts=, Symbol Duration (Micro Sec) %%%%%%%%%%
    
23. Ts=ts+D;
    
24. st1=ts/N;
    
25. %%%%%%% Ng=, Number of Samples for Gurd Interval %%%%%%%
    
26. Ng=round(D/(ts/N));
    
27. %%%%%%% Nt=, Number of Samples for a Symbol %%%%%%%
    
28. Nt=(N+Ng);
    
29. %%%%%%% NNt=, Number of Samples for a Flame %%%%%%
    
30. NNt=Nt*L;
    
31. %%%%%%%%% Sampling frequency (usec) %%%%%%%%%%
    
32. tbw=1/st1;
    
33. %%%%%%% tsw=, Total Allocated Signal Bandwidth (MHz) %%%%%%%
    
34. tsw=(1/ts*M);%%%% W bandwidth
    
35. ddf=tbw/NNt; %%%% Frequency resolution
    
36. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    
37. dt=0.1;%%%%%%  delay spread
    
38. ds=st1;%%%%%%  delay spacing
    
39. NP=10;  %%%%%% number of delay path
    
40. 
    
41. %%% Power Delay profile with  Exponential decay constant
    
42. amp(1)=0.7854;
    
43. amp(2)=0.4861;
    
44. amp(3)=0.3009;
    
45. amp(4)=0.1863;
    
46. amp(5)=0.1153;
    
47. amp(6)=0.0714;
    
48. amp(7)=0.0442;
    
49. amp(8)=0.0273;
    
50. amp(9)=0.0169;
    
51. amp(10)=0.0105;
    
52. dts1(1:NP)=0:9;
    
53. %[amp,dst,dts1]=f_MUL(NP,dt,ds,st1);
    
54. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    
55. cn=30;%%% dB
    
56. cn1=10^(-cn/10);
    
57. 
    
58. LLL=1;%%% Number of trial
    
59. for KLL=1:LLL;
    
60. if mod(KLL,1)==0,KLL
    
61.   end
    
62. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    
63.   zxn1=zeros(1,NP);
    
64.   zyn1=zeros(1,NP);
    
65.   zn1=zeros(1,NP);
    
66.   zn2=zeros(1,NP);
    
67.   phn=zeros(1,NP);
    
68.   amp1=zeros(1,NP);
    
69.   qd3=zeros(1,NNt);
    
70.   %%% Generation of Rayleigh fading
    
71.   %%% Amplitude
    
72.   zxn1(1:NP)=randn(1,NP);
    
73.   zyn1(1:NP)=randn(1,NP);
    
74.   zn1(1:NP)=zxn1(1:NP)+j*zyn1(1:NP);
    
75.   zn2(1:NP)=abs(zn1(1:NP))/sqrt(2);
    
76.   %%% Phase
    
77.   phn(1:NP)=atan2(zyn1(1:NP),zxn1(1:NP));
    
78.   amp1(1:NP)=zn2(1:NP).*amp(1:NP).*exp(j*phn(1:NP));
    
79. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    
80. ya=zeros(L,M);
    
81. x3=zeros(L,N);
    
82. L1=N/2+1-M/2;
    
83. L2=N/2+M/2;
    
84. %%%%%%%%%%%%%Data generation %%%%%%%%%%%%%%
    
85. ya(1:L,1:M)=randint(L,M,MMMa);
    
86. %%%%%%%%%%%%% Modulation %%%%%%%%%
    
87. x3(1:L,L1:L2)=f_EnMQAM(ya(1:L,1:M),MMMa);
    
88. %%%%%%%%%%%Converting from Frequency to Time domain signal %%%%%%%%%
    
89. for k=1:L;
    
90. zz1(k,1:N)=ifft(fftshift(x3(k,1:N)))*sqrt(N);
    
91. %%%% Adding Guard Interval
    
92. z3(k,1:Nt)=[zz1(k,N-Ng+1:N) zz1(k,1:N)];
    
93. end
    
94.   q13=z3';
    
95.   q73=q13(:)';
    
96.   %%%%%%%%%% Evaluation of Power Spectrum under AWGN condition
    
97.   q73a=fftshift(fft(q73));
    
98.   pow1=q73a.*conj(q73a);
    
99.   pow2=10*log10(pow1/max(pow1));
    
100.   %%%%%%%%%%%
     
101.   po3=mean(q73.*conj(q73));
     
102.   c3=po3/2*cn1;
     
103.   %%%%%% Noise Generation %%%%%
     
104.      zxc(1:L,1:Nt)=sqrt(c3).*randn(L,Nt);
     
105.      zyc(1:L,1:Nt)=sqrt(c3).*randn(L,Nt);
     
106.      znc(1:L,1:Nt)=zxc(1:L,1:Nt)+j*zyc(1:L,1:Nt);
     
107.      znn1c=znc';
     
108.      znnc=znn1c(:)';
     
109.      
     
110.      qd3(1:NNt)=amp1(1).*q73(1:NNt);
     
111.      %%%% Generation of Multi-path fading signal
     
112.   for k=2:NP;
     
113.      qu23(k,1:NNt)=[q73(NNt+1-dts1(k):NNt) q73(1:NNt-dts1(k))];
     
114.      qu23(k,1:NNt)=amp1(k).*qu23(k,1:NNt);
     
115.      qd3(1:NNt)=qd3(1:NNt)+qu23(k,1:NNt);
     
116.   end
     
117.   %%%%%%%%%% Evaluation of Power Spectrum under multi-path fading condition
     
118.   qd3a=fftshift(fft(qd3));
     
119.   pow3=qd3a.*conj(qd3a);
     
120.   pow4=10*log10(pow3/max(pow3));
     
121.   %%%% Adding AWGN
     
122.   q73x=qd3+znnc;
     
123.   q73y=q73+znnc;
     
124. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     
125. imax=1;
     
126. %%% Removing Guard interval
     
127. for k=1:L;
     
128.      p93(k,1:Nt)=q73x(imax-1+(k-1)*Nt+(1:Nt));
     
129.      p993(k,1:N)=[p93(k,Ng+1:N+Ng)];
     
130.      %%%%%%%%%%  FFT %%%%%
     
131.      p813(k,1:N)=fftshift(fft(p993(k,1:N))/sqrt(N));
     
132.      HH3(1:M)=p813(1,L1:L2)./x3(1,L1:L2);
     
133.      %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     
134.      p8x3(k,1:M)=p813(k,L1:L2)./HH3(1:M);
     
135.      %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     
136.      p93y(k,1:Nt)=q73y(imax-1+(k-1)*Nt+(1:Nt));
     
137.      p993y(k,1:N)=[p93y(k,Ng+1:N+Ng)];
     
138.      %%%%%%%%%%%%%%%%%%%%%%%%%%%%
     
139.      p813y(k,1:N)=fftshift(fft(p993y(k,1:N))/sqrt(N));
     
140.      p8y3(k,1:M)=p813y(k,L1:L2);
     
141.      %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     
142.     end
     
143.    
     
144.     %%% Demodulation of signal under AWGN
     
145.   pb1(1:L,1:M)=f_DeMQAM(p8x3(1:L,1:M),MMMa);%%%
     
146.   %%% evaluation of bit error rate performance
     
147.   per1(KLL)=biterr(pb1(2:L,1:M),ya(2:L,1:M))/(M*(L-1)*MMM1a);
     
148.   %%% Demodulation of signal under multi-path fading
     
149.   pb2(1:L,1:M)=f_DeMQAM(p8y3(1:L,1:M),MMMa);%%%
     
150.   per2(KLL)=biterr(pb2(2:L,1:M),ya(2:L,1:M))/(M*(L-1)*MMM1a);
     
151. end
     
152. %%%% Final BER
     
153. ERR1=mean(per1(1:LLL));
     
154. ERR2=mean(per2(1:LLL));
     
155. 
     
156. %%%%%%%%%%%%%%%%%%%%%%%%
     
157. figure(1)%%%%%% Information Real Data in Freq
     
158. stem(real(x3(2,1:N)))
     
159. grid on
     
160. figure(2)%%%%%% Information Imag Data in Freq
     
161. stem(imag(x3(2,1:N)))
     
162. grid on
     
163. figure(3)%%%%%% Time domain signal
     
164. plot(abs(z3(1,1:Nt)))
     
165. grid on
     
166. figure(4)
     
167. plot(abs(z3(1,1:Ng)))
     
168. grid on
     
169. figure(5)
     
170. plot(abs(z3(1,Nt-Ng:Nt)))
     
171. grid on
     
172. figure(6)
     
173. plot(pow2)
     
174. grid on
     
175. figure(7)
     
176. plot(pow4)
     
177. grid on
     
178. figure(8)
     
179. plot(abs(HH3))
     
180. grid on
     
181. figure(9)
     
182. stem(real(p8x3(2,1:M)))
     
183. grid on
     
184. figure(10)
     
185. stem(imag(p8x3(2,1:M)))
     
186. grid on
     
187. figure(11)
     
188. plot(p8x3(2:L,1:M),'x')
     
189. grid on
     
190. figure(12)
     
191. plot(p8y3(2:L,1:M),'x')
     
192. grid on
     
193. 
     
194. 
     
195. 
     
196. etime(clock,t0)/60

复制代码

zzuj

正在学习这个,真是太感谢了:)

zhouwh

randint 是什么意思？

花如月

help randint

rockzone

有错误啊。

f_EnMQAM  这是啥东西呢？

shin142

thank you very much

haobaobao521

是啊，有错误啊，
??? Undefined function or variable 'f_EnMQAM'.

Error in ==> E:\MATLAB6p5\work\Untitled333.m
On line 87  ==> x3(1:L,L1:L2)=f_EnMQAM(ya(1:L,1:M),MMMa);
谁能给解释下啊
怎么改？
刚开始学，不大懂

ChaChing

太长了, 懒, 没细看
可能是自订函数吧, 楼主可能为给齐