diff --git a/src/lte/test/reference/lte_link_budget.m b/src/lte/test/reference/lte_link_budget.m index 77fffa848..efa6a0aa6 100644 --- a/src/lte/test/reference/lte_link_budget.m +++ b/src/lte/test/reference/lte_link_budget.m @@ -1,18 +1,27 @@ +clear all; +close all; + ## LTE from theory to practice ## Table 22.7 Reference sensitivity. - f = 2160e6; # carrier freq Hz, EARFCN = 500 (downlink) -n = -107.5 # noise power dBm, corresponds to 5 MHz BW +nrbs = 25; # tx bandwdith configuration in number of RBs +bw = nrbs * 180000; # bandwidth in Hz, note that this is smaller than + # the nominal Channel Bandwdith, see TS 36.101 fig 5.6-1 +kT = -174; # noise PSD in dBm / Hz +n = kT + 10*log10(bw); # noise power dBm p = 30; # tx power dBm -nf = 5; # receiver noise figure in dB +txPsd = p - 10*log10(bw); # power / bandwidth in linear units +nf = 9; # receiver noise figure in dB d = logspace (0,5,100); g = 10.*log10 (gain_freespace(d,f)); # propagation gain in dB -snr = p + g - n - nf ; #dB + +snr = p + g - n - nf; # dB +##snr = txPsd + g - kT - nf ; # dB -semilogx (d, snr); +semilogx (d, snr, ";friis;"); xlabel ("distance (m)"); ylabel ("SNR (dB)"); title ("LTE link budget");