[問題] OFDM 的效能
我最近在研究OFDM的系統。
我有一些疑惑,希望強者解答^^。
OFDM是將signal做fft調制之後傳出去,然後再做解調的動作。
那這樣的話效能上會變好ㄇ?
我跑的模擬效能有變好,可是察了一些書他們都說不會變,這裡我好困惑喔!
我用了兩個modulation去模擬,但是效果上差異很大。
16 QAM 的效能變好,BER vs Eb/N0的圖形比理論值差了一些距離。
BPSK的效能超好的,因為我加的AWGN Noise幾乎都沒有辦法讓我的信號錯誤。
我這邊真的很不懂耶!
怎麼可能呢?
snr = 10^(snr_dB/10);
N = 1/snr;
N0 = 10*log10(N/2);
noise = wgn(10,2,N0);
%noise
noisen = zeros(10,1);
noisen = noise(:,1)/sqrt(2)- j*noise(:,2)/sqrt(2);
bf = bf + noisen;
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