Suppose that you are asked to design a 16.8-kb/s constellation for a wireless voiceband modem. The symbol rate is 2400 symbols/s and the SNR received is 28 dB.
(a) For an uncoded constellation, find the alphabet size and select a constellation. Give your reasons for the selection. Using the asymptotic bound, give the symbol error rate for the modem.
(b) Repeat part (a) for a trellis-coded constellation with a 3-dB coding gain.