LTE定位参考信号生成程序与标准不一致？
在定位参考信号映射到资源单元中时，频域上位置与LTE协议标准中的不一样，一直找不到原因，麻烦各路大神帮帮忙！下面附录的是程序代码！主程序：%PRS定位参考信号clc;close all;clear all;%信道为20MHz系统的参数设置N_fft=2048; % FFT点数N_used_subcarrier=1200; %可用的子载波个数fs=30.72e6; %系统采样频率Ts=1/fs; %系统采样间隔N_DL_RB=100; %资源块数目（传输带宽18MHz）N_PRS_RB=100; %分配给PRS的资源块数N_RB_SC=12; %每个资源块的子载波数% N_id_1 = 9; %物理层小区ID组 0 <= N_ID_1<=167% N_id_2 = 1; %物理层小区ID组中的物理层ID 0 <= N_ID_2<=2% N_cell_id = 3* N_id_1 + N_id_2; % 物理层小区ID 0-503N_cell_id=5;subframe_index=1; %子帧号0--9PBCH_port=1; %物理广播信道天线端口数：1、2或4N_CP=1; %常规循环前缀：1；扩展循环前缀：0switch N_CP case 0, N_DL_symb=6; case 1, N_DL_symb=7; otherwise N_DL_symb=7;endSNR=25; %信噪比% 定位参考信号映射到资源单元上recv_subframe = zeros(N_DL_RB*N_RB_SC,N_DL_symb*2);recv_subframe = rs_mapping_to_subframe_PRS(recv_subframe,subframe_index,N_cell_id,PBCH_port,N_PRS_RB,N_CP,N_DL_RB); %定位参考信号 recv_subframe = rs_mapping_to_subframe(recv_subframe,subframe_index,N_cell_id,0,N_DL_RB,N_CP); %小区参考信号% recv_subframe = rs_mapping_to_subframe(recv_subframe,subframe_index,N_cell_id,1,N_DL_RB,N_CP); %小区参考信号% recv_subframe = rs_mapping_to_subframe(recv_subframe,subframe_index,N_cell_id,2,N_DL_RB,N_CP); %小区参考信号% recv_subframe = rs_mapping_to_subframe(recv_subframe,subframe_index,N_cell_id,3,N_DL_RB,N_CP); %小区参考信号%---IFFT---recv_subframe =;IFFTed=zeros(N_fft,N_DL_symb*2);for i=1:N_DL_symb*2 IFFTed(:,i)=sqrt(N_fft)*ifft(recv_subframe(:,i),N_fft);end%---加CP----WithCP_sequence=zeros(2208,N_DL_symb*2);for i=1:14 WithCP_sequence(:,i)=CP_Insert(IFFTed(:,i).',0);endsend_signal=reshape(WithCP_sequence,1,length(WithCP_sequence)*size(WithCP_sequence,2));%---信道---%---AWGN---recv_signal=awgn(send_signal,SNR);%---去CP---recv_WithCP_sequence=reshape(recv_signal,2208,N_DL_symb*2);NoCP_sequence=zeros(N_DL_symb*2,N_fft); for i=1:N_DL_symb*2 NoCP_sequence(i,:)=CP_Removal(recv_WithCP_sequence(:,i),0);end NoCP_sequence=NoCP_sequence.'; %----FFT----- FFTed=zeros(N_fft,N_DL_symb*2); for i=1:N_DL_symb*2 FFTed(:,i)=1/sqrt(N_fft)*fft(NoCP_sequence(:,i),N_fft); end %---去资源映射---调用函数：function subframe = rs_mapping_to_subframe (subframe,sub_index,N_cell_id,p,N_DL_RB,N_CP);% *************************************************************************% Function Description: (v1.0---20090513 by jiangyoubang)% This function is used for the progress of mapping the reference signals% to the relevant position in the radio subframe of antana port p in 3GPP LTE.%% usage :% subframe = rs_mapping_to_subframe (subframe,sub_index,N_cell_id,p,N_DL_RB,N_CP);% % input parameter :% "subframe" : the data subframe that reference signal needs to add into.% "sub_index" : the subframe index in a radio frame. range:0~9% "N_cell_id" : Physical layer cell identity.% "N_CP" : For normal CP,N_CP=1; for extended CP,N_CP=0;% "p" : The antena number % "N_DL_RB" : Downlink bandwidth configuration. it might be 6,25,50,100% % note : % the generalization of the reference signal sequence% can be found in Ref.36.211.850 %**************************************************************************% parameter that can be found in Ref.36.211-850N_RB_DL_MAX = 110;v_shift = mod(N_cell_id,6);% For N_CP=1, means normal CP; For N_CP=0, means extended CP; switch N_CP case 0, N_DL_symb = 6; case 1, N_DL_symb = 7; otherwise N_DL_symb = 7;end% different p means different antana port, and the mapping process is different%参考于《移动宽带技术》----扇区参考信号定义（p79）switch p case 0, %the subframe will go to antana port 0 for ns= 2 * sub_index : 2 * sub_index + 1 kk=mod(ns,2); l=0;%如果p=0且l=0时，v=0（参考移动宽带技术——扇区参考信号定义） v=0; r_l_ns = gen_rs_seq (N_cell_id,N_CP,ns,l);% generate rs sequence for m = 0 : 2 * N_DL_RB - 1 m1 = m + N_RB_DL_MAX - N_DL_RB + 1; k = (6 * m + mod((v + v_shift),6)) + 1; subframe(k,l + N_DL_symb * kk + 1) = r_l_ns(m1); %mapping rs to subframe end l=N_DL_symb - 3;%N_DL_symb=7 v=3; r_l_ns = gen_rs_seq (N_cell_id,N_CP,ns,l);% generate rs sequence for m = 0 : 2 * N_DL_RB - 1 m1 = m + N_RB_DL_MAX - N_DL_RB + 1; k = 6 * m + mod((v + v_shift),6) + 1; subframe(k,l + N_DL_symb * kk + 1) = r_l_ns(m1);%mapping rs to subframe end end case 1, %the subframe will go to antana port 1 for ns= 2 * sub_index : 2 * sub_index + 1 kk=mod(ns,2); l=0; v=3; r_l_ns = gen_rs_seq (N_cell_id,N_CP,ns,l);% generate rs sequence for m = 0 : 2 * N_DL_RB - 1 m1 = m + N_RB_DL_MAX - N_DL_RB + 1; k = 6 * m + mod((v + v_shift),6) + 1; subframe(k,l + N_DL_symb * kk + 1) = r_l_ns(m1);%mapping rs to subframe end l=N_DL_symb - 3; v=0; r_l_ns = gen_rs_seq (N_cell_id,N_CP,ns,l);% generate rs sequence for m = 0 : 2 * N_DL_RB - 1 m1 = m + N_RB_DL_MAX - N_DL_RB + 1; k = 6 * m + mod((v + v_shift),6) + 1; subframe(k,l + N_DL_symb * kk + 1) = r_l_ns(m1);%mapping rs to subframe end end case 2, %the subframe will go to antana port 2 for ns= 2 * sub_index : 2 * sub_index + 1 kk=mod(ns,2); l=1; v=3*mod(ns,2); r_l_ns = gen_rs_seq (N_cell_id,N_CP,ns,l);% generate rs sequence for m = 0 : 2 * N_DL_RB - 1 m1 = m + N_RB_DL_MAX - N_DL_RB + 1; k = 6 * m + mod((v + v_shift),6) + 1; subframe(k,l + N_DL_symb * kk + 1) = r_l_ns(m1);%mapping rs to subframe end end case 3, %the subframe will go to antana port 3 for ns= 2 * sub_index : 2 * sub_index + 1 kk=mod(ns,2); l=1; v=3+3*mod(ns,2); %mod((v + v_shift),6) r_l_ns = gen_rs_seq (N_cell_id,N_CP,ns,l);% generate rs sequence for m = 0 : 2 * N_DL_RB - 1 m1 = m + N_RB_DL_MAX - N_DL_RB + 1; k = 6 * m + mod((v + v_shift),6) + 1; subframe(k,l + N_DL_symb * kk + 1) = r_l_ns(m1);%mapping rs to subframe end end otherwise disp('illagal antana port number p .');end function subframe = rs_mapping_to_subframe_PRS (subframe,sub_index,N_cell_id,PBCH,N_PRS_RB,N_CP,N_DL_RB);% *************************************************************************% This function is used for the progress of mapping the reference signals% to the relevant position in the radio subframe of antana port p in 3GPP LTE.% % usage :% subframe = rs_mapping_to_subframe (subframe,sub_index,N_cell_id,p,N_DL_RB,N_CP);% % input parameter :% "subframe" : the data subframe that reference signal needs to add into.% "sub_index" : the subframe index in a radio frame. range:0~9% "N_cell_id" : Physical layer cell identity.% "N_CP" : For normal CP,N_CP=1; for extended CP,N_CP=0;% "p" : The antena number % "N_DL_RB" : Downlink bandwidth configuration. it might be 6,25,50,100% % note : % the generalization of the reference signal sequence% can be found in Ref.36.211.850 %**************************************************************************N_RB_DL_MAX = 110; v_shift = mod(N_cell_id,6);% N_CP=1, 常规循环前缀P；N_CP=0, 扩展循环前缀; switch N_CP case 0, N_DL_symb = 6; case 1, N_DL_symb = 7; otherwise N_DL_symb = 7;end% 定位参考信号映射到资源单元上if N_CP==1 %常规循环前缀 for ns = 2 * sub_index : 2 * sub_index + 1 kk=mod(ns,2); if kk==0 l=; %OFDM符号的序号 elseif (kk==1)&&(PBCH==1||PBCH==2) %kk=1且（1个或2个物理广播信道天线端口） l=; %OFDM符号的序号 elseif (kk==1)&&(PBCH==4) %kk=1且（4个物理广播信道天线端口） l=; %OFDM符号的序号 end for i=1:length(l) r_l_ns = gen_rs_seq (N_cell_id,N_CP,ns,l(i)); % 产生定位参考信号序列 for m = 0: 2 * N_PRS_RB-1 m1 = m + N_RB_DL_MAX - N_PRS_RB+1; k=6*(m+N_DL_RB-N_PRS_RB)+mod((6-l(i)+v_shift),6)+1; %k为子载波序号 subframe(k,l(i)+N_DL_symb*kk+1) = r_l_ns(m1); %参考信号序列映射到复值调制符号（天线端口6） end end endelse %扩展循环前缀 for ns= 2 * sub_index : 2 * sub_index + 1 kk=mod(ns,2); if kk==0 %l的取值 l=; elseif (kk==1)&&(PBCH==1||PBCH==2) l=; elseif (kk==1)&&(PBCH==4) l=; end for i=1:length(l) r_l_ns = gen_rs_seq (N_cell_id,N_CP,ns,l(i)); % 产生定位参考信号序列 for m = 0 : 2 * N_PRS_RB - 1 m1 = m + N_RB_DL_MAX - N_PRS_RB; k=6*(m+N_DL_RB-N_PRS_RB)+mod((5-l(i)+v_shift),6)+1; subframe(k,l(i)+N_DL_symb*kk+1) = r_l_ns(m1); %参考信号序列映射到复值调制符号（天线端口6） end end endend% % different p means different antana port, and the mapping process is different% %参考于《移动宽带技术》----扇区参考信号定义（p79）% switch p% case 0, %the subframe will go to antana port 0% for ns= 2 * sub_index : 2 * sub_index + 1% kk=mod(ns,2);% l=0;%如果p=0且l=0时，v=0（参考移动宽带技术——扇区参考信号定义）% v=0;% r_l_ns = gen_rs_seq (N_cell_id,N_CP,ns,l);% generate rs sequence% for m = 0 : 2 * N_DL_RB - 1% m1 = m + N_RB_DL_MAX - N_DL_RB + 1;% k = (6 * m + mod((v + v_shift),6)) + 1;% subframe(k,l + N_DL_symb * kk + 1) = r_l_ns(m1); %mapping rs to subframe% end% % l=N_DL_symb - 3;%N_DL_symb=7% v=3;% r_l_ns = gen_rs_seq (N_cell_id,N_CP,ns,l);% generate rs sequence% for m = 0 : 2 * N_DL_RB - 1% m1 = m + N_RB_DL_MAX - N_DL_RB + 1;% k = 6 * m + mod((v + v_shift),6) + 1;% subframe(k,l + N_DL_symb * kk + 1) = r_l_ns(m1);%mapping rs to subframe% end% end% case 1, %the subframe will go to antana port 1% for ns= 2 * sub_index : 2 * sub_index + 1% kk=mod(ns,2);% l=0;% v=3;% r_l_ns = gen_rs_seq (N_cell_id,N_CP,ns,l);% generate rs sequence% for m = 0 : 2 * N_DL_RB - 1% m1 = m + N_RB_DL_MAX - N_DL_RB + 1;% k = 6 * m + mod((v + v_shift),6) + 1;% subframe(k,l + N_DL_symb * kk + 1) = r_l_ns(m1);%mapping rs to subframe% end% % l=N_DL_symb - 3;% v=0;% r_l_ns = gen_rs_seq (N_cell_id,N_CP,ns,l);% generate rs sequence% for m = 0 : 2 * N_DL_RB - 1% m1 = m + N_RB_DL_MAX - N_DL_RB + 1;% k = 6 * m + mod((v + v_shift),6) + 1;% subframe(k,l + N_DL_symb * kk + 1) = r_l_ns(m1);%mapping rs to subframe% end % end% case 2, %the subframe will go to antana port 2% for ns= 2 * sub_index : 2 * sub_index + 1% kk=mod(ns,2);% l=1;% v=3*mod(ns,2);% r_l_ns = gen_rs_seq (N_cell_id,N_CP,ns,l);% generate rs sequence% for m = 0 : 2 * N_DL_RB - 1% m1 = m + N_RB_DL_MAX - N_DL_RB + 1;% k = 6 * m + mod((v + v_shift),6) + 1;% subframe(k,l + N_DL_symb * kk + 1) = r_l_ns(m1);%mapping rs to subframe% end% end% case 3, %the subframe will go to antana port 3% for ns= 2 * sub_index : 2 * sub_index + 1% kk=mod(ns,2);% l=1;% v=3+3*mod(ns,2);% %mod((v + v_shift),6)% r_l_ns = gen_rs_seq (N_cell_id,N_CP,ns,l);% generate rs sequence% for m = 0 : 2 * N_DL_RB - 1% m1 = m + N_RB_DL_MAX - N_DL_RB + 1;% k = 6 * m + mod((v + v_shift),6) + 1;% subframe(k,l + N_DL_symb * kk + 1) = r_l_ns(m1);%mapping rs to subframe% end% end% case 6,%the subframe will go to antana port 6% for ns= 2 * sub_index : 2 * sub_index + 1% kk=mod(ns,2);% % otherwise disp('illagal antana port number p .');% end function rs_seq_l_ns = gen_rs_seq (N_cell_id,N_CP,ns,l);% *************************************************************************% Function Description: (v1.0---20090428 by )% This function is used for the progress of generation of the reference % signal sequence that is needed by cell_specific reference signal% in 3GPP LTE.%% usage :% rs_seq_l_ns = gen_rs_seq (N_cell_id,N_CP,ns,l);% % input parameter :% "N_cell_id" : Physical layer cell identity.% "N_CP" : For normal CP,N_CP=1; for extended CP,N_CP=0;% "ns" : The slot number within a radio frame% "l" : The OFDM symbol number within the slot% % output parameter :% "rs_seq_l_ns": the reference_signal sequence needed by 3GPP TDD-LTE% % note : % the generalization of the reference signal sequence% can be found in Ref.36.211.850 %**************************************************************************% N_cell_id= 17;% N_CP = 1;% ns=1;% l=4;%parameter needed,can be found in LTE reference 36.211-850N_RB_DL_MAX=110;%generation of gold sequence(生成Gold序列)gold_seq = gen_gold_seq(N_cell_id,N_CP,ns,l);%generation of reference sequence（生成参考序列）rs_seq_l_ns = zeros(1,N_RB_DL_MAX * 2);for m = 1 : N_RB_DL_MAX * 2 rs_seq_l_ns(m)=(1/sqrt(2)) * ( (1-2*gold_seq(2*m-1)) + (1-2*gold_seq(2*m))*j );end function gold_seq_out = gen_gold_seq (N_cell_id,N_CP,ns,l)% *************************************************************************% Function Description: (v1.0---20090428 by )% This function is used for the progress of generation of gold sequence % that is needed by cell_specific reference signal in 3GPP LTE.% % usage :% gold_seq_out = gen_gold_seq (N_cell_id,N_CP,ns,l)% % input parameter（输入参数）:% "N_cell_id" : Physical layer cell identity.% "N_CP" : For normal CP,N_CP=1; for extended CP,N_CP=0;% "ns" : The slot number within a radio frame% "l" : The OFDM symbol number within the slot% % output parameter :% "gold_seq_out": the gold_seq needed by 3GPP TDD-LTE,% it starts at c(1601) and with a length of (N_RB_DL_MAX+1)*4% note : % the initialization of the m-sequence can be found in 36.211.850.%**************************************************************************% N_cell_id= 17;% N_CP = 1;% ns=1;% l=4;%parameter needed,can be found in LTE reference 36.211-850N_RB_DL_MAX=110;NC=1600;%generation of the first m-sequence x1.(产生第一个m序列x1)% the length of x1 needed at least is N_RB_DL_MAX*4+NCx1=zeros(1,(N_RB_DL_MAX+1)*4+NC);x1(1)=1;%the values of x1(32)---x1((N_RB_DL_MAX+1)*4+NC-31)for k = 1 : (N_RB_DL_MAX+1) * 4 + NC - 31 x1(k+31)=mod((x1(k+3)+x1(k)),2);endx1;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%generation of the second m-sequence x2.（产生第二个m序列x2）% the length of x2 needed at least is (N_RB_DL_MAX)*4+NCx2=zeros(1,(N_RB_DL_MAX+1)*4+NC);%the initialization of the first 31 values of x2;x2(1) = N_CP;for k=1:9 x2(k+1)=bitget(N_cell_id,k); %information of cell id endother21bits=(7*(ns+1)+l+1)*(N_cell_id*2+1);for k=1:21 x2(k+10)=bitget(other21bits,k); %initialization of the other 21 bits;end%the values of x2(32)---x2((N_RB_DL_MAX+1)*4+NC-31)for k=1:(N_RB_DL_MAX+1)*4+NC-31 x2(k+31)=mod((x2(k+3)+x2(k+2)+x2(k+1)+x2(k)),2);endx2;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%the generation of the gold sequence cn;gold_seq_out=zeros(1,(N_RB_DL_MAX+1)*4);for k=1:(N_RB_DL_MAX+1)*4 gold_seq_out(k)=mod((x1(k+NC)+x2(k+NC)),2);end%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 很实用，下载学习下，谢谢楼主！
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