Coded Modulation Performance

This chapter compares the faster than Nyquist (FTN)‐style schemes to competing methods. The older ideas have bandwidth consumption in between the new ones and binary error correcting codes. The chapter reviews several older coded modulations that achieve moderate bit densities in the range 2‐‐4 bits/Hz‐s. It explores set‐partition codes. The CPM (continuous phase modulation) codes are then discussed. Also based on carrier modulation, CPM is an older method that adds a far reaching constraint: the transmitted signal has a constant envelope. Some FTN implementations in the literature are also reviewed, including chip designs. Some databits drive the subset selection and the rest are carried in the chosen subset. Like FTN, CPM can be coded or uncoded. A more natural bandwidth measure for CPM is 99% or higher power‐in‐band (PIB). The chapter also introduces how to convert signal bit densities from one bandwidth criterion to another.