Low peak-to-average power ratio transmission in frequency-division multiple access systems

A base station in a multiple-access communication system that uses multiple subcarriers, comprising:

• a controller, which is arranged to allocate first subcarriers to a first communication terminal for transmitting first data, and second subcarriers to a second communication terminal for transmitting second data, to assign the first communication terminal to modulate the first data onto at least some of the first subcarriers using a first multi-carrier modulation scheme to produce a first signal, and to assign the second communication terminal to modulate the second data onto at least some of the second subcarriers using a second multi-carrier modulation scheme having a reduced peak-to-average power ratio (PAPR) relative to the first multi-carrier modulation scheme to produce a second signal;
• a transmitter, which is arranged to respectively communicate the allocated first and second subcarriers to the first and second communication terminals;
• and
• a receiver, which is arranged to communicate simultaneously with the first and second communication terminals by simultaneously receiving the first and second signals over the first and second subcarriers,
• wherein the receiver is arranged to receive the second signal over multiple different communication channels via multiple antennas, and to decode the second data from the second signal using a decision-directed decoding procedure that processes all subcarriers in parallel by;
• producing a plurality of soft symbols based on a respective plurality of received and equalized symbols, which are respectively received over at least some of the second subcarriers;
• applying a Fourier transform to the soft received symbols;
• providing outputs of the Fourier transform to multiple slicers to produce hard symbol decisions based on the respective soft received symbols;
• and
• applying an inverse Fourier transform to the hard symbol decisions.

A multiple access communication system that uses multiple subcarriers, comprising:

• a base station, which is arranged to allocate first subcarriers for transmission using a first multi-carrier modulation scheme, to allocate second subcarriers for transmission using a second multi-carrier modulation scheme having a reduced peak-to-average power ratio (PAPR) relative to the first multi-carrier modulation scheme, to respectively communicate the allocated first and second subcarriers to the first and second communication terminals, and to simultaneously receive uplink data respectively transmitted using the first and second multi-carrier modulation schemes over the first and second subcarriers;
• a first communication terminal, which is arranged to modulate first data onto at least some of the first subcarriers using the first multi-carrier modulation scheme to produce a first signal, and to transmit the first signal to the base station;
• and a second communication terminal, which is arranged to modulate second data onto at least some of the second subcarriers using the second multi-carrier modulation scheme to produce a second signal, and to transmit the second signal to the base station,
• wherein the base station is arranged to receive the second signal over multiple different communication channels via multiple antennas, and to decode the second data from the second signal using a decision-directed decoding procedure that processes all subcarriers in parallel by;
• producing a plurality of soft symbols based on a respective plurality of received and equalized symbols, which are respectively received over at least some of the second subcarriers;
• applying a Fourier transform to the soft received symbols;
• providing outputs of the Fourier transform to multiple slicers to produce hard symbol decisions based on the respective soft received symbols;
• and
• applying an inverse Fourier transform to the hard symbol decisions.