Peak to average power ratio reduction methodology for QAM communications systems

In an quadrature amplitude modulation (QAM) communication system comprised of a composite signal having an average power level and a peak power level, for transmission on a communication channel, which composite signal is comprised of a plurality of QAM subchannel signals combined together, each of said QAM subchannel signals being comprised of:

• a) a plurality of complex-valued QAM information symbols, each of which information symbols are located substantially on one of n where n is an integer constellation points of a complex plane, each point being defined by a discrete magnitude and phase angle from a predetermined reference;
• and b) complex-valued pilot symbols combined with said QAM information symbols at predetermined pilot symbol times over a predetermined time period, each pilot symbol having a magnitude and phase;
• a method of reducing the ratio of the peak power level to average power level in said composite signal comprised of:
• during a finite time period during which a plurality of QAM subchannels has at least one, pilot symbol:
• at least one of said QAM subchannel signals, has a first-valued pilot (fixed pilot QAM subchannel signals);
• in at least one other QAM subchannel signal, combining with said QAM information symbols, a second-valued pilot symbol to form a second QAM subchannel signal;
• combining said fixed pilot QAM subchannel signals with said second QAM subchannel signal to form a composite signal;
• and
• transmitting said composite signal on said communication channel.

In an n-level quadrature amplitude modulation (QAM) communication system comprised of a composite signal having an average power level and a peak power level, for transmission on a communication channel, which composite signal is comprised of a plurality of QAM subchannel signals combined together, each of said QAM subchannel signals being comprised of:

• a) a plurality of complex-valued QAM information symbols, each of which information symbols are, located substantially on one of n where n is an integer constellation points of a complex plane;
• and b) complex-valued pilot symbols combined with said QAM information symbols at predetermined pilot symbol times, each pilot symbol having a magnitude and phase;
• a method of reducing the ratio of the peak power level to average power level in said composite signal comprised of:
• in a first QAM subchannel signal, combining with QAM information symbols thereon, at said pilot symbol times, at least one pilot symbol selected from a first set of complex, non-fixed-values, to form said first QAM subchannel signal;
• in a second QAM subchannel signal, combining with QAM information symbols thereon, at said pilot symbol times, at least one pilot symbol selected from a second set of complex, non-fixed-values, to form said second QAM subchannel signal;
• combining said first and second QAM subchannel signals with at least one other QAM subchannel signal to form a composite signal;
• and
• transmitting said composite signal on said communication channel.

In a quadrature amplitude modulation (QAM) communication system comprised of a composite signal for transmission on a communication channel, which composite signal is comprised of a plurality of QAM subchannel signals combined together, of which each QAM subchannel signal includes:

• a) QAM information symbols (QAM symbols), said QAM symbols having an average power level and having a peak power level over a finite length of time;
• and b) a plurality of predetermined complex-valued pilot symbols, each having a magnitude and phase, and that are combined with said QAM symbols, said complex-valued pilot symbols having an average power level and having a peak power level over a finite length of time, a method of reducing the ratio of the peak power level to average power level in said composite signal comprised of:
• selecting phase angles for a plurality of fixed-amplitude pilot symbols for a plurality of said subchannels, which pilot symbols can include both constellation based, and non-constellation-based pilot symbols (preselected pilot symbols), to minimize the peak-to-average power ratio of the composite signal over a finite length of time;
• combining said preselected pilot symbols for each subchannel with QAM symbols on said subchannel to form piloted QAM subchannel symbol streams;
• and
• transmitting combined preselected pilot symbols and QAM symbols on said communication channel.

In a quadrature amplitude modulation (QAM) communication system comprised of a composite signal for transmission on a communication channel, which composite signal is comprised of a plurality of QAM subchannel signals combined together, of which each QAM subchannel signal includes:

• a) QAM information symbols (QAM symbols), said QAM symbols having an average power level and having a peak power level over a finite length of time;
• and b) a plurality of complex-valued pilot symbols, each having a magnitude and phase, and that are combined with said QAM symbols, said complex-valued pilot symbols having an average power level and having a peak power level over a finite length of time, a method of reducing the ratio of the peak power level to the average power level in said composite signal comprised of:
• selecting phase angles for a plurality of fixed-amplitude pilot symbols for a plurality of said subchannels, which pilot symbols can include both constellation based, and non-constellation-based pilot symbols (preselected pilot symbols), to minimize the peak-to-average power ratio of the composite signal over a finite length of time;
• combining said preselected pilot symbols for each subchannel with QAM symbols on said subchannel;
• and
• transmitting the combined preselected pilot symbols and QAM symbols on said communication channel.

In a quadrature amplitude modulation (QAM) communication system comprised of a composite signal for transmission on a communication channel, which composite signal is comprised of a plurality of QAM subchannel signals combined together, of which each QAM subchannel signal includes:

• a) QAM information symbols (QAM symbols), said QAM symbols having an average power level and having a peak power level over a finite length of time;
• and b) a plurality of complex-valued pilot symbols, each having a magnitude and phase, and that are combined with said QAM symbols, said complex-valued pilot symbols having an average power level and having a peak power level over a finite length of time, a method of reducing the ratio of the peak power level to the average power level in said composite signal comprised of:
• selecting magnitudes and phase angles for a plurality of pilot symbols for a plurality of said subchannels, which pilot symbols can be both constellation based, and non-constellation based, (preselected pilot symbols) to minimize the peek-to-average power ratio of complex-valued composite signals over a finite length of time;
• combining said preselected pilot symbols for each subchannel with QAM symbols on said subchannel;
• transmitting the combined preselected pilot symbols and QAM symbols on said communication channel.

In an quadrature amplitude modulation (QAM) communication system comprised of a composite signal for transmission on a communication channel, which composite signal is comprised of a plurality of QAM subchannel signals combined together, at least one of which QAM subchannel signal includes:

• a) a plurality of complex-valued information symbols, each of which information symbols are located substantially on one of n where n is an integer constellation points of a complex plane, each constellation point being defined by a discrete magnitude and discrete phase angle from a predetermined reference point in the complex plane;
• and b) a plurality of predetermined complex-valued pilot symbols, each having a magnitude and phase, each of said plurality of QAM subchannel signals having an average power level and having a peak power level over a finite length of time, a method of reducing the ratio of the peak power level to average power level in said composite signal comprised of:
• selecting phase angles for a plurality of fixed-amplitude pilot symbols for a plurality of said subchannels (preselected pilot symbols) such that at least one of said complex-valued pilot symbols is a non-constellation-based pilot symbol;
• combining said preselected pilot symbols for each subchannel with QAM symbols on said subchannel to form piloted QAM subchannel symbol streams;
• and
• transmitting the combined preselected pilot symbols and QAM symbols on said communication channel.

In an quadrature amplitude modulation (QAM) communication system comprised of a composite signal, having a peak power level and an average power level, for transmission on a communication channel, which composite signal is comprised of a plurality of QAM subchannel signals combined together, at least one of which QAM subchannel signal includes:

• a) a plurality of complex-valued QAM information symbols, each of which information symbols are located substantially on one of n where n is an integer constellation points of a complex plane, each constellation point being defined by a discrete magnitude and discrete phase angle from a predetermined reference point in the complex plane;
• and b) a plurality of predetermined complex-valued pilot symbols, combined with the QAM information symbols over a finite length of time, each having a magnitude and phase, each of said plurality of QAM subchannel signals having an average power level and having a peak power level over a finite length of time, a method of reducing the ratio of the peak power level to average power level in said composite signal comprised of:
• combining at least one of said complex-valued QAM information symbols, with a plurality of complex-valued, non-constellation-based pilot symbols, having a plurality of phase angles, to form at least one QAM subchannel signal;
• combining said QAM subchannel signal with at least one other QAM subchannel signal to form a composite signal;
• and
• transmitting said composite signal on said communication channel.