The gr-comm_tools module implements a BPSK and QPSK phase ambiguity solvers based on a sync word detection.
Three blocks are included, a BPSK phase ambiguity resolver for data streams, a QPSK phase ambiguity resolver for data streams and a BPSK/QPSK phase ambiguity resolver for messages
In the docs folder there is a pdf explained the theory behind using standard blocks, the hier blocks from the pdf are included in the examples folder
To install comm_tools, you should clone the repository and:
mkdir build cd build cmake .. make sudo make install sudo ldconfig
The module can be uninstalled using:
cd build sudo make uninstall sudo ldconfig
This block will solves the 90º phase rotation and invertion ambiguity in a QPSK demodulated signal when the signal has ASM
The input signal is the demodulated bit stream with phase ambiguity and the output is the same signal but with the ambiguity solved
(R): Run-time adjustable
Set the number of bit than can be “skipped” from the ASM correlation as ASM bit error ignoring
Set syncword to look for Phase Ambiguity resolution as hex string, the hex string could have an odd number of characters
Set the command message send through the message port when ASM is detected
The pair (Lock Msg, phase value) message sent when the ASM is detected. Phase value integer could be 0, 90, 180, 270, -0, -90, -180, -270
This example flowgraph qpsk_phase_ambiguity_solver_test_v1.grc is located in the gr-com_tools package
In this example, the bytes of and input files are convolutional codec and QPSK modulated. The modulated signal is rotated 0º, 90º, 180º or 270º and each of these rotation are I-Q inverted. A Selector allows to choose with signal is demodulated. At the QPSK demodulator output, a QPSK Phase ambiguity solver will resolve the phase ambiguity and the “fixed” signal is decode and the the PDUs when Syncmark start are generated and stored in an output file.
This block will solves the 180º phase ambiguity in a BPSK demodulated signal when the signal has a sync mark (ASM)
The input signal is the demodulated bit stream with phase ambiguity and the output is the same signal but with the ambiguity solved
(R): Run-time adjustable
Set the number of bit than can be “skipped” from the ASM correlation as ASM bit error ignoring
Set syncword to look for Phase Ambiguity resolution as hex string
Set the command message send through the message port when ASM is detected
The pair (Lock Msg, phase value) message sent when the ASM is detected. Phase value integer could be 0 or 180
This example flowgraph bpsk_phase_ambiguity_solver_test_v1.grc is located in the gr-com_tools package
In this example, the bytes of and input files are BPSK modulated. The modulated signal is rotated 0º, or 180º. A Selector allows to choose with signal is demodulated. At the BPSK demodulator output, a BPSK Phase ambiguity solver will resolve the phase ambiguity and the “fixed” signal is decode and the the PDUs when Syncmark start are generated and stored in an output file.
This block is based on the QPSK and BPSK Ambiguity solvers for streams but for PDUs. It takes a constellation QPSK or BPSK output data bytes and fix the phase ambiguity using ASM when constellation modulation is applied will solves the 180º phase ambiguity in a BPSK demodulated signal when the signal has a sync mark (ASM)
The input signal is the demodulated bits message with phase ambiguity and the output is the same bit message but with the ambiguity solved
(R): Run-time adjustable
Set if the input data is from a BPSK or QPSK demodulator
Set the number of bit than can be “skipped” from the ASM correlation as ASM bit error ignoring
Set syncword to look for Phase Ambiguity resolution as hex string
Set the command message send through the message port when ASM is detected
The pair (Lock Msg, phase value) message sent when the ASM is detected. Phase value integer could be 0 or 180
This example flowgraph pdu_phase_ambiguity_solver_test_v1.grc is located in the gr-com_tools package
In this example, a number of vector sources is used to generated demodulated BPSK and QPSK data with the ASM in all the phase rotation, the PDU Phase ambiguity solver will resolve the phase ambiguity and the output data shall match the expected one.