A received signal includes a plurality of user signals, the plurality of user signals including at least a first user signal and a second user signal. The first user signal corresponds to first user data that has been modulated independently of second user data corresponding to the second user signal. At least one of the first user signal or the second user signal is encoded with a finite state machine encoder independently of the other of the first user signal and the second user signal. The received signal is demodulated, wherein demodulating the received signal includes calculating distances between (i) each transmit symbol in the received signal and (ii) expected symbol values, wherein each expected symbol value corresponds to user data for multiple users including the first user and the second user. User data in the received signal including the first user data and the second user data is decoded based on the calculated distances.