Dears, I am doing some analysis on channel state information of OFDM signals. I used GNURadion rx_ofdm.grc (gnuradio/gr-digital/examples/ofdm at main · gnuradio/gnuradio) for signal transmission and reception through a channel model block. Then, the CSI has been extracted using Tag debug block. After that, I used matlab to plot the phase of pilot signals from csi. When I set the noise voltage on the channel block to zero, the phase of each pilot signal is constant. However, when I set the noise voltage to 100m, the phases of the pilot signals vary over time as shown in Fig. (phase_pilot). I used a moving average filter to mitigate the noise impact on the pilot phase. The results were better, but still there is a phase drop as shown in Fig. (phase_pilot_filter). As I read, the phase should be constant as long as the environment is static. So, why there is a phase drop? how that can be fixed?
Thanks,HZ | | | | | | | | | | | gnuradio/gr-digital/examples/ofdm at main · gnuradio/gnuradio GNU Radio – the Free and Open Software Radio Ecosystem - gnuradio/gr-digital/examples/ofdm at main · gnuradio/gn... | | |
