Re: Problems with packet communication using BPSK

[Shruti Gupta]

Hi!

I know that without any packet structure in '1', the received data is being decoded as "AAAAAA......" or "55555.....". Is that what you meant by inverted bit stream? I am not really clear about what you meant by phase ambiguity?

    Thanks
    SG

On 10/08/20 12:20 pm, Shruti Gupta wrote:

Hi all!

I am working on implementing  BPSK communication system with SDR in GNURadio. I tried implementing packet-communication in GNURadio using two systems each acting as TX and RX. Using the examples provided in gr-digital , I tried running TX and RX with LimeSDR Mini, but was unable to get them to work. In order to identify and solve the issues, I moved on to implementing everything in step-wise approach, as in-

1. Transmit just alternating 1’s and 0’s using BPSK modulation and receiving it on other end using synchronization and demodulation.
   
2. Introduce packet structure into the previous raw-communication model .
   
3. Then add FEC into the system and finally include CRC and achieve the same packet-communication as provided with gr-digital.
   

In this step-wise approach, I was able to get raw communication model (point 1 in above) work properly. However, I am not able to get packet version (number 2) working. I used the same system settings just the introduction of packet structure at TX and correlation estimation & header-payload demux at RX but still no luck. Is there some issue with the way I am implementing packet formation at TX or the correlation estimator is the problem? You can find my implementation at following link:

https://drive.google.com/drive/folders/1TIWhNuVmclenhLj4qJK2HT-er6RoCcco?usp=sharing

Any suggestions/pointers in order to resolve the issue will be helpful.

Thanks and Regards
SG