A method for multiplexing multiple data streams for transmission in a single radio channel, the method comprising, in a radio transmitter device and for at least a first interval of time: for a first stream of data bits, generating a first stream of N -symbol sequences by successively precoding each data bit or group of data bits in the first stream of data bits, wherein said precoding comprises mapping each data bit or group of data bits to a corresponding one of a set of predetermined N- symbol sequences according to the value of the data bit or group of data bits, wherein the predetermined N -symbol sequences are selected so that each N- symbol sequence, when fed into a GMSK or 8PSK modulator, yields an output corresponding to a tone out of a predetermined set of tones falling within a predetermined channel bandwidth, each tone occupying only a fraction of the predetermined channel bandwidth; for a second stream of data bits, generating a second stream of N -symbol sequences by successively precoding each data bit or group of data bits in the second stream of data bits, wherein said precoding comprises mapping each data bit or group of data bits to a corresponding one of the set of predetermined N -symbol sequences according to the value of the data bit or group of data bits; modulating a carrier signal with the first and second streams of N -symbol sequences, using Gaussian Minimum-Shift Keying, GMSK, or Phase-Shift Keying, PSK, modulation, so that tones corresponding to the first and second streams of data bits simultaneously occupy the predetermined channel bandwidth, wherein said modulating comprises rotating symbols in at least one of the streams of N -symbol sequences or corresponding I/Q samples such that the resulting modulated symbols for the first stream have a different rotation angle than the modulated symbols for the second stream and the tones corresponding to the first stream of data bits are different to the tones corresponding to the second stream of data bits. for a first stream of data bits, generating a first stream of N -symbol sequences by successively precoding each data bit or group of data bits in the first stream of data bits, wherein said precoding comprises mapping each data bit or group of data bits to a corresponding one of a set of predetermined N- symbol sequences according to the value of the data bit or group of data bits, wherein the predetermined N -symbol sequences are selected so that each N- symbol sequence, when fed into a GMSK or 8PSK modulator, yields an output corresponding to a tone out of a predetermined set of tones falling within a predetermined channel bandwidth, each tone occupying only a fraction of the predetermined channel bandwidth; for a second stream of data bits, generating a second stream of N -symbol sequences by successively precoding each data bit or group of data bits in the second stream of data bits, wherein said precoding comprises mapping each data bit or group of data bits to a corresponding one of the set of predetermined N -symbol sequences according to the value of the data bit or group of data bits; modulating a carrier signal with the first and second streams of N -symbol sequences, using Gaussian Minimum-Shift Keying, GMSK, or Phase-Shift Keying, PSK, modulation, so that tones corresponding to the first and second streams of data bits simultaneously occupy the predetermined channel bandwidth, wherein said modulating comprises rotating symbols in at least one of the streams of N -symbol sequences or corresponding I/Q samples such that the resulting modulated symbols for the first stream have a different rotation angle than the modulated symbols for the second stream and the tones corresponding to the first stream of data bits are different to the tones corresponding to the second stream of data bits.