WP4000 - Study task list

[drowe67]

Place holder for misc detailed tasks in #19

Deliverable is freedv_low study (Latex doc equalisation.m, acquisition.m):

• Acquisition - simulate additive sine waves
• Simulate speech (SSB)
• supplementary filtering (does filtering help or hinder), test acquisition, equalisation.
• complete fine frequency section, establish target/threshold std dev, try combining information from two pilots, table of worst case for a few channels, probability of successful acquisition for std dev. Is it significant?
• Modify equalisation.m sim to use any pilot value (e.g. Barker), (like acquisition.m). Currently assumes all pilots 1's. Update MSE expressions in Latex doc for any pilot value.
• build up one or more of the nastier channel models from DRM. Add perf curves for these. We'd like to get a feel if our new waveform can handle long distance paths OK.
• some automated tests to make sure simulation code doesn't break. A few checks from equalisation.m and acquisition.m would be enough, add GitHub action.
• set up correct Ts, Tcp, Nuw etc to get Rb=1400 bit/s over the channel with 4ms CP
• A few days looking into single carrier modems, now FCC has removed 300 baud limit. Pros and cons? PAPR reduction. How to deal with ISI. Any reduction in Lcp? Maybe a first pass simulation. Its need RN filtering, what is PAPR of RN filtered QPSK?
• discussion of wingman pilots. Decn - do we keep them? They add 2Rs to the bandwidth. I imagine we can get away without them. They add annoying (Nc+2) factors everywhere.
• document new waveform parameters (e.g. in spreadsheet or latex doc). Diagram of modem frame showing pilots, wingman pilots.