BPSK Implementation

Transmitter

BPSK Transmitter Flow Graph Include mainly consist of the following

File Source : for File processing processing

File Processing

it sends preamble first , then data, file name , #EOF
File processing is in the sense that , it is a embedded python block, it reads data for example if you have a file

hi im arun 
hi im arun

then , the the EPB(Embedded Python Block) will first read the say 10Bytes "hi im arun" , then transmits it , under the hood , it first sends a preamble like %UUUU] , then the data("hi im arun") then a post filter "#EOF" for marking it is the end of file .

Stream CRC32 : It computes the 32 bit checksum for the data
Protocol Formater : adds a header with acccess code
Tagged Stream MUX : multiplex it to gether (combines header and payload)
Constellation Modulator : modulate to the constellations $- S (t) \cos ω t$ and $- S (t) \cos ω t$

sps: 4
dif_encoding: true
excess_bw: 0.35
FFT Filter : It is used to shape the signal spectrum
Fractional Resambler : It is used to resample the signal to get the desired sampling rate , 48K to 768k
Pluto Sink : It is used to transmit the signal

Receiver

BPSK Receiver Flow Graph Include mainly consist of the following

Pluto Source : It is used to receive the signal
AGC : used to automaticaly adjust the gain
FLL Band Edge : carrier frequency synchronization
Symbol Sync : symbol timing reecovery
Costas Loop : phase recovery
BPSK Demodulator
Diff Decoder
Detect Access Code
Repack Bits 1 -> 8 because the demodulation happens at bit level in gnu radio

Before repacking: [0x01, 0x00, 0x01, 0x01, 0x00, 0x00, 0x01, 0x00] (8 bytes representing 8 bits)

After repacking: [0x5A] (1 byte containing all 8 bits: 01011010 in binary)

Stream CRC : Check the CRC

expects byte-aligned data to properly verify the checksum

File Sink : It is used to save the data