Hi.. I found the mistake which i was doing in digital_bert_tx.py file. i was always transmitting 1 but after scrambling when we do packing then according to this statement self._pack = blocks.unpacked_to_packed_bb(self._mod.bits_per_symbol(), gr.GR_MSB_FIRST) in qpsk modulation in place of 1 it will take 2 bits 0 and 1 so in receiver there will be two bits in place of only 1 thats why the error is >10%. i tried to correct it by replacing self._mod.bits_per_symbol() to a constant 1 both in qpsk and bpsk and calculated BER for both. For bpsk i used bit rate 250kbits/second and for qpsk i used 500kbits/second. By setting these data rates i am getting same SNR for Both but not same BER. Do i need to change any other parameter for qpsk? if any one has any idea about it please tell me.
Best Regards, Hitesh On Tue, Oct 13, 2015 at 12:13 AM, Hitesh Kasera <hiteshkase...@gmail.com> wrote: > Hi everyone, > I am trying to calculate BER for bpsk and qpsk using digital_bert_tx.py > and digital_bert_rx.py. i want to compare BER of qpsk and bpsk. At same SNR > around 20db i am getting constant .16 BER for qpsk and for bpsk it is > 1e-12. when i change the SNR using gain of Transmitter and Receiving end > there is no change in BER for qpsk, for bpsk its changes. I am not able to > understand why with qpsk its not working. if anyone has any idea or anyone > who has calculated BER previously please help me. > > Best Regards, > Hitesh >
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