WP4000 - Octave Simulation

[drowe67]

Using the recommendations from the freedv_low study, modify the OFDM modem Octave simulation to run the new waveform. This should be an option, i.e. don't break support for existing waveforms.

• [ ] Decide on waveform name. We might need a series, e.g. rc1,rc2
• [ ] Is Octave->ofdm_xx->freedv_xx still the best development process to use? Might depend on other help we get.
• [ ] fix codec2/octave/doppler_spread (see changes made to freedv_low) version
• [ ] ofdm_tx, ofdm_rx functional test working with new waveform (e.g. AWGN at Eb/No=4dB), spot check of BER
• [ ] ofdm_tx, ofdm_rx performance test working with new waveform on AWGN, MPP, MPD. BER/PER curves. Similar BER/PER to freedv_low study.
• [ ] support Nd1, Nd=2. Show improved performance with Nd=2.
• [ ] ofdm_ldpc_tx,ofdm_ldpc_rx
• [ ] new ctests to sopt check he new waveform