Data Rate Nomenclature We should agree upon a common scheme for describing the various data rates in a system that works for optical communication – In some proposals, data rate values refer to bit streams prior to FEC encoding; others cite data rate values for bit streams post FEC encoding – In addition, there can be some confusion regarding channel symbol rates (especially for PPM where M slots comprise a single symbol) – We may leverage previous CCSDS agreements

From CCSDS Green Book “Bandwidth Efficient Modulations”

Interleaver Nomenclature In each of the discussed coding proposals, there are interleaver(s) proposed In discussion, we’ve resolved confusion as to the interleaver’s purpose Interleavers in the ESA/DLR proposal (CCSDS standard for Reed-Solomon) and in the NASA SCPPM code definition are to avoid the bursty errors common to FEC decoding schemes Interleavers in the NASA proposals have extensive memory depths to mitigate fading on atmospheric optical links Recommendation: to avoid confusion, we should label each as a “code interleaver” or a “channel interleaver”