ofdm中的ls算法LS algorithm in OFDM.docx

1、ofdm中的ls算法LS algorithm in OFDMofdm中的ls算法（LS algorithm in OFDM）基于梳状导频的ofdm信道估计% ifft_bin_length：和的点数IFFT FFTcarrier_count：子载波个数%bits_per_symbol：每符号上的比特数% symbols_per_carrier：每桢的OFDM符号数X：欲发送的二进制比特流%清除所有；中图分类号；ifft_bin_length = 128；%和的点数IFFT FFTcarrier_count = 100；% % %子载波个数bits_per_symbol = 2；%每符号上的比特

2、数symbols_per_carrier = 12；%每桢的OFDM符号数李= 7；%导频之间的间隔NP =细胞（carrier_count /里县）+ 1；% % 1导频数加的原因：使最后一列也是导频n_number = carrier_count * * bits_per_symbol symbols_per_carrier；载体= 1：carrier_count +NP；GI = 8；%保护间隔长度n_snr = 25；%每比特信噪比信噪比= 5；%信噪比间隔% symbols_per_carrier *（ifft_bin_length + GI）% -%向量初始化X =零（1，n_nu

3、mber）； ；x2 ；X3 = ；X4 = ；X5 = ；X6 = ；X7 = ；Y1 = ；Y2 = ；Y3 = ；Y4 = ；Y5 = ；Y6 = ；Y7 = ；XX =零（1，n_number）；dif_bit =零（1，n_number）；dif_bit1 =零（1，n_number）；dif_bit2 =零（1，n_number）；dif_bit3 =零（1，n_number）；randint（x = 1，n_number）；%产生二进制随即序列（非0即1）% -%的QPSK调制：（1 1）-4；（0，1）- 34；（0，0）- 34；（1,0）- -/ 4；S =（X2-1）/

4、sqrt（2）；S = S（1:2：n_number）；图像= S（2:2：n_number）；X1 = S + J *图像；% -%产生随机导频信号% -train_sym = randint（1,2 symbols_per_carrier）；T =（train_sym。* 2-1）/ sqrt（2）；请= T（1:2:2 * symbols_per_carrier）；图像= T（二时02分02秒* symbols_per_carrier）；training_symbols1 =治疗+ J *图像；training_symbols2 = training_symbols1。”；trainin

5、g_symbols = repmat（training_symbols2,1，NP）；%显示（training_symbols）试验1：李+ 1 = carrier_count +NP；如果长度（导频）= NP飞行员= 试点，carrier_count +名词；结束% -%串并转换X2 =重塑（X1，carrier_count，symbols_per_carrier）。”；% -%插入导频信号= 1：carrier_count +NP；信号（导频）= ；X3（：，飞行员）= training_symbols；X3（：，信号）= x2；% X3 =猫（1，training_symbols，X2）

6、；ifft_modulation =零（symbols_per_carrier，ifft_bin_length）；ifft_modulation（：，携带者）= x3；% ifft_modulation（：，conjugate_carriers）=连词（X3）；X4 = IFFT（ifft_modulation，ifft_bin_length，2）；%X5=X4.;% plus protection interval (cyclic prefix)For k=1:symbols_per_carrier;For i=1:IFFT_bin_length;X6 (k, i+GI) =X4 (k, I

7、);EndFor i=1:GI;X6 (k, I) =X4 (k, i+IFFT_bin_length-GI);EndEnd%-% parallel string conversionX7=reshape (X6., 1, symbols_per_carrier* (IFFT_bin_length+GI);% f=100; r=pi/6;% for n=1:length (X7)% a (n) =cos (2*pi*n) /8);% a (n) =exp (i* (2*pi*f*n) / (8*length (X7) +r);%c=X7.*a (n);% end% b=real (X7.*a)

8、;% m1=xcorr (b (?), 1:136);% m2=xcorr (b (?), 137:272);%a=zeros (1000271);%for i=1:1000% b=xcorr (X7 (?), 1:136);% c=xcorr (X7 (?), 137:272);% a (I,:) =b;%end%-% channel model: Rayleigh fading channel with Doppler shiftFd=100;% Doppler frequency shiftR=6;% multipath numberA=0.123 0.3 0.4 0.5 0.7 0.8

9、;% multipath amplitudeD=2 3459 13;% diameter delayT=1;% system sampling periodTh=90 072144216 288*pi./180;% phase shiftH=ones (1, carrier_count);Hh=;For k=1:r%deta=zeros (1, D (k) -1), 1, zeros (1, carrier_count-d (k);H1=a (k) *exp (j* (2*pi*T*fd*d (k) /carrier_count);%h1=a (k) *exp (j* (2*pi*T*fd*d

10、 (k) /carrier_count);Hh=hh, h1;EndH (d+1) =hh;%noise=randn (1, length (X7) +j.*randn (1, length (X7);%-Channel1=zeros (size (X7);Channel1 (1+d (1): length (X7) =hh (1) *X7 (1:length (X7) -d (1);Channel2=zeros (size (X7);Channel2 (1+d (2): length (X7) =hh (2) *X7 (1:length (X7) -d (2);Channel3=zeros

11、(size (X7);Channel3 (1+d (3): length (X7) =hh (3) *X7 (1:length (X7) -d (3);Channel4=zeros (size (X7);Channel4 (1+d (4): length (X7) =hh (4) *X7 (1:length (X7) -d (4);Channel5=zeros (size (X7);Channel5 (1+d (5): length (X7) =hh (5) *X7 (1:length (X7) -d (5);Channel6=zeros (size (X7);Channel6 (1+d (6

12、): length (X7) =hh (6) *X7 (1:length (X7) -d (6);%-Tx_data=X7+channel1+channel2+channel3+channel4;%-%-%-% plus Gauss white noiseError_ber=;% bit error rateError_ber1=;Error_ber2=;% bit error rateError_ber3=;Error_ber11=;%Error_ser=;% symbol error rateFor snr_db=0:snr:N_snr% code_power=0;% code_power

13、=norm (Tx_data)2/ (length (Tx_data);Symbol power of the% signal%bit_power=var (Tx_data);% bit_power=code_power/bits_per_symbol;% bit power% noise_power=10*log10 (bit_power/ (10 (snr_db/10)% noise power% noise=wgn (1, length (Tx_data), noise_power,complex);% produces GAUSS white noise signalVn=randn

14、(1, symbols_per_carrier* (IFFT_bin_length+GI) +sqrt (-1) *randn (1, symbols_per_carrier* (IFFT_bin_length+GI);Vn=vn/norm (VN) *10 (-snr_db/20) *norm (Tx_data);Y7=Tx_data+vn;%-% string merge transformationY6=reshape (Y7, IFFT_bin_length+GI, symbols_per_carrier);Y6_1=reshape (Tx_data, IFFT_bin_length+

15、GI, symbols_per_carrier);% to protect intervalsFor k=1:symbols_per_carrier;For i=1:IFFT_bin_length;Y5 (k, I) =Y6 (k, i+GI);Y5_1 (k, I) =Y6_1 (k, i+GI);EndEndY4=fft (Y5, IFFT_bin_length, 2);Y3=Y4 (: carriers);Y4_1=fft (Y5_1, IFFT_bin_length, 2);Y3_1=Y4_1 (: carriers);%-%LS channel estimationH=;Y2=Y3

16、(: signal);Y2_1=Y3_1 (: signal);Rx_training_symbols=Y3 (: pilot);Rx_training_symbols_1=Y3_1 (: pilot);Rx_training_symbols0=reshape (Rx_training_symbols, symbols_per_carrier*Np, 1);Rx_training_symbols0_1=reshape (Rx_training_symbols_1, symbols_per_carrier*Np, 1);Training_symbol0=reshape (training_sym

17、bols, 1, symbols_per_carrier*Np);Training_symbol0_1=reshape (training_symbols, 1, symbols_per_carrier*Np);Training_symbol1=diag (training_symbol0);Training_symbol1_1=diag (training_symbol0_1);%disp (training_symbols)Training_symbol2=inv (training_symbol1);Hls=training_symbol2*Rx_training_symbols0;Hl

18、s1=reshape (Hls, symbols_per_carrier, Np);HLs=;HLs1=;If ceil (carrier_count/LI) =carrier_count/LIFor k=1:Np-1HLs2=;For t=1:LIHLs1 (=: 1) = (Hls1 (?), k+1) -Hls1 (?), K) * (t-1)./LI+Hls1 (k);HLs2=HLs2, HLs1;EndHLs=HLs, HLs2;EndElseFor k=1:Np-2HLs2=;For t=1:LIHLs1 (=: 1) = (Hls1 (?), k+1) -Hls1 (?), K

19、) * (t-1)./LI+Hls1 (k);HLs2=HLs2, HLs1;EndHLs=HLs, HLs2;EndHLs3=;For t=1:mod (carrier_count, LI)HLs1 (=: 1) = (Hls1 (?), Np) -Hls1 (?), Np-1) * (t-1)./LI+Hls1 (Np-1);HLs3=HLs3, HLs1;End;HLs=HLs, HLs3;End%Hls1=Hls.;training_symbol2_1 = inv（training_symbol1_1）；hls_1 = training_symbol2_1 * rx_training_

20、symbols0_1；hls1_1 =重塑（hls_1，symbols_per_carrier，NP）；hls_1 = ；hls1_1 = ；如果细胞（carrier_count /李）= = carrier_count /里县K = 1：NP-1hls2_1 = ；对于t = 1：李hls1_1（：，1）=（hls1_1（：，K + 1）- HLS1（：，k）*（t-1）。/李+ HLS1（：，k）；hls2_1 = hls2_1，hls1_1 ；结束hls_1 = hls_1，hls2_1 ；结束其他的K = 1：NP-2hls2_1 = ；对于t = 1：李hls1_1（：，1）=（hl

21、s1_1（：，K + 1）- hls1_1（：，k）*（t-1）。/锂离子hls1_1（：，k）；hls2_1 = hls2_1，hls1_1 ；结束hls_1 = hls_1，hls2_1 ；结束hls3_1 = ；T = 1：MOD（carrier_count，李）hls1_1（：，1）=（hls1_1（：，NP）- hls1_1（：，NP-1）*（t-1）。/锂离子hls1_1（：，NP-1）；hls3_1 = hls3_1，hls1_1 ；结束；hls_1 = hls_1，hls3_1 ；结束% h = repmat（HLS1，symbols_per_carrier，1）；%将导频扩展

22、成symbols_per_carrier * carrier_count矩阵Y1，Y2，HLS；h_2 = IFFT（HLS，100,2）；h_3 =零（12100）；h_3（：，1:8）= h_2（：，1:8）；h_4 = FFT（h_3100,2）；% h_2_1 = IFFT（hls_1，ifft_bin_length，2）；Y11 = Y2。/ h_4；% Y11 = Y2。/% -% -%并串变换YY =重塑（Y2。，1，n_number / bits_per_symbol）；YY1 =重塑（Y1。，1，n_number / bits_per_symbol）；yy11 =重塑（Y11

23、。，1，n_number / bits_per_symbol）；% -QPSK解调%y_real =符号（房（YY）；y_image =符号（图像（YY）；y_re = y_real / sqrt（2）；y_im = y_image / sqrt（2）；y_real1 =符号（房（YY1）；y_image1 =符号（图像（YY1）；y_re1 = y_real1 / sqrt（2）；y_im1 = y_image1 / sqrt（2）；y_real11 =符号（房（yy11）；y_image11 =符号（图像（yy11）；y_re11 = y_real11 / sqrt（2）；y_im11 =

24、 y_image11 / sqrt（2）；r00 = ；R01 = ；R10 = ；R11 = ；R110 = ；R111 = ；K = 1：长度（y_real）；r00 = r00， y_real（K），y_image（K） ；结束；K = 1：长度（y_real1）；R10 = R10， y_real1（K），y_image1（K） ；结束；K = 1：长度（y_real11）；R110 = R10， y_real11（K），y_image11（K） ；结束；K = 1：长度（y_re）；R01 = R01， y_re（K），y_im（K） ；结束；K = 1：长度（y_re1）；R11

25、= R11， y_re1（K），y_im1（K） ；结束；K = 1：长度（y_re11）；R111 = R111，y _ re11 (k), and _ im1 (k);end;% xx (find (r01 0) = 1;% -% 计算在不同信噪比下的误比特率并作图the _ bits = s - pl1.the _ date) = s - r11.the _ bit11 = s - r111;on _ snr = 0% 纪录误比特数for k = 1: n _ number;if the _ bits (k) = 0;on _ snr = on _ snr + 1;endend;on _

26、 snr1 = 0% 纪录误比特数for k = 1: n _ number;if the _ date) (k) = 0;on _ snr1 = on _ snr1 + 1;endendon _ snr11 = 0% 纪录误比特数for k = 1: n _ number;if the _ bit11 (k) = 0;on _ snr11 = on _ snr11 + 1;endenderror _ ber = error _). the _ snr;error _ ber1 = error _ ber1. the _ snr1;error _ ber11 = error _ ber11. the _ snr11;% margin = (sum (unit, 1 / 12;% mse = abs (margin (h) / (h);endon = zeros (1, length (0: n _ snr snr);