Multi-level modulation apparatus, multi-level demodulation apparatus, multi-level modulation/demodulation communication system, program and modulation/demodulation method

A apparatus for demodulating a communication signal to output a demodulated data signal of 3p+1 strings, where p is an integer not less than 3, said apparatus comprising:

• a multi-level demodulating unit for demodulating said communication signal to output a demodulated received data string signal;
• a serial-to-parallel conversion circuit, receiving and time-division demultiplexing said received demodulated data string signal, to output first, second and third demodulated data string signals;
• and
• a data inverse-conversion circuit, receiving said first, second and third demodulated data string signals to output said demodulated data signal of (3p+1) strings;
• wherein
• if said first demodulated data string signal takes on a value from 1 to 8×2(p−2), said data inverse-conversion circuit receives signals representing predetermined (11/8)×2p and (10/8)×2p values, as second and third demodulated data string signals, respectively;
• if said first demodulated data string signal takes on a value from 1+8×2(p−3) to 8×2(p−3)+3×2(p−3), said data inverse-conversion circuit receives signals representing predetermined (8/8)×2p and (6/8)×2p values, as second and third demodulated data string signals, respectively;
• and
• said data inverse-conversion circuit outputs the demodulated data taking on a predetermined value, based on the values indicated by said first, second and third demodulated data string signals, as said (3p+1) strings of said demodulated data.

A computer program product causing a computer composing a multi-level modulation apparatus to execute the processing of multi-level modulation of (3p+1) strings of an input data signal, where p is an integer not less than 3;

• said program causing said computer to execute the processing of converting said input data signal into first, second and third conversion data, in such a manner that
• said first conversion data takes on a value from 1 to (11/8)×2p depending on the value of said input data signal;
• if said first conversion data takes on a value from 1 to 8×2(p−3), said second and third conversion data take on predetermined (11/8)×2p and (t0/8)×2p values, depending on the value of said input data signal, respectively;
• and
• if said first conversion data takes on a value from 1+8×2(p−3) to 8×2(p−3)+3×2(p−3) values, said second and third conversion data take on predetermined (8/8)×2p and (6/8)×2p values, respectively, depending on the value of said input data signal;
• said program causing said computer to execute the processing of sequentially outputting said first to third conversion data to a multi-level demodulating unit.

A computer program product causing a computer composing a multi-level demodulation apparatus to perform the processing of multi-level demodulation of a communication signal and outputting a demodulated data signal of (3p+1) strings, where p is an integer not less than 3, said program causing said computer to execute a conversion process which receives said communication signal as demodulated first to third data string signals and converts the received signals into a demodulated signal of (3p+1) strings;

• said, conversion process receiving (11/8)×2p values as said first demodulated data string signal;
• if said first demodulated signal takes on a value from 1 to 8×2(p−3), said conversion process receiving predetermined (11/8)×2p and (10/8)×2p values as said second and third demodulated data string signals, respectively;
• if said first demodulated signal takes on a value from 1+8×2(p−3) to 8×2(p−3)+3×2(p−3), said conversion process receiving predetermined (8/8)×2p and (6/8)×2p values as said second and third demodulated data string signals, respectively;
• and
• said conversion process outputting a demodulated data signal of (3p+1) strings, said demodulated data signal taking on a predetermined value, based on the values indicated by said first to third demodulated data string signals.

A method of performing multi-level modulating/demodulation in which (3p+1) strings of an input signal are allocated to three modulation symbols, where p is an integer not less than 3, said method comprising, the steps of:

• allocating (11/8)×2p signal points as a first modulation symbol;
• in case of said first modulation symbol taking 1 to 8×2(p−3) signal points, using (11/8)×2p and (10/8)×2p signal points, predetermined in association with said input signal as second and third modulation symbols;
• and
• in case of said first modulation symbol taking 1+8×2(p−3) to 8×2(p−3)+3×2(p−3) points, using (8/8)×2p and (6/8)×2p signal points, predetermined in association with said input signal, respectively, as said second and third modulation symbols.

A modulation apparatus comprising:

• converting means, receiving an input signal that takes on a value from 1 to a (3p+1)st power of 2, where p is an integer not less than 3, to generate and output first to third converted data based on said input signal;
• and
• means, receiving said first to third converted data output from said converting means, to effect multi-level modulation thereon to output the resulting data;
• said converting means classifying said input signal, depending on the values thereof, into two predetermined groups not having common elements, said converter means having means for executing conversion such that
• if said input signal belongs to said first group, said first converted data takes on a value form 1 to 8×2(p−3), depending on the value of said input signal, said second and third converted data taking on predetermined (11/8)×2p and (10/8)×2p values, allocated depending on the value of said input signal, respectively;
• and
• if said input signal belongs to said second group, said first converted data takes on a value from 1+8×2(p−3) to 8×2(p−3)+3×2(p−3), depending on the value of said input signals, said second and third converted data taking on (8/8)×2p and (6/8)×2p values, allocated depending on the value of said input signal, respectively.

A method of performing modulation, comprising the steps of:

• converting a data signal of (3p+1) strings, where p is an integer not less than 3, to three signals, each being a (p+1) string and having a predetermined relation to one another,
• allocating the three signal of (p+1) string separately to three phase planes, and
• performing multi-level modulation, with the three phase planes as a set, by controlling respective numbers of signal points in the three phase planes;
• wherein an multi-level quadrature amplitude modulation (QAM) is carried out, in which equivalently (p+1/3) bits are allocated to each modulation symbol and the n-ary number is approximated to 2(p+1/3).

An apparatus for performing multi-level modulation of an input data string to output a communication signal, said apparatus comprising:

• a data string number conversion circuit for converting said input data string into an input data signal made up by 3p+2 strings of binary signals, where p is an integer not less than 2, and for outputting said input data signal;
• a first data conversion circuit, receiving said input data signal output from said data string number conversion circuit, for converting said input data signal to output the converted input data signal;
• a second data conversion circuit, receiving said input data signal output from said data string number conversion circuit and an output signal of said first data conversion circuit, for converting the received signals into three sets of output signals, termed first, second and third output signals, each being a (p+1) string output signal;
• a parallel-to-serial conversion circuit, receiving said three sets of (p+1) string output signals output by said second data conversion circuit, for performing time-division multiplexing of said three sets of (p+1) string output signals to output resulting output signals;
• and
• a multi-level modulating unit, receiving said output signal of said parallel-to-serial conversion circuit, for effecting multi-level modulation to output the communication signal;
• wherein
• said first data conversion circuit outputs the output signal indicating values from 1 to (7/4)×2p, responsive to the value of said input data signal;
• if the output signal of said first data conversion circuit takes on a value from 1 to 4×2(p−2), said second data conversion circuit sets, based on said input data signal, the value of the output signal of said first data conversion circuit as said first output signal and outputs signals representing predetermined (7/4)×2p and (7/4)×2p values as said second and third signals, respectively;
• if the output signal of said first data conversion circuit takes on a value from 1+4×2(p−2) to 4×2(p−2)+2×2(p−2), said second data conversion circuit sets the value of the output signal of said first data conversion circuit as said first output signal and outputs signals representing predetermined (7/4)×2p and 1×2p values as said second and third signals, respectively;
• and
• if the output signal of said first data conversion circuit takes on a value from 1+4×2(p−2)+2×2(p−2) to 4×2(p−2)+2×2(p−2)+1×2(p−2), said second data conversion circuit sets the value of the output signal of said first data conversion circuit as said first output signal and outputs signals representing predetermined 1×2p and (1/4)×2p values as said second and third signals, respectively.

An apparatus for performing multi-level modulation of an input data string to output a communication signal, said apparatus comprising:

• a data string number conversion circuit for converting said input data string into an input data signal made up by (3p+2) strings of binary signals, where p is an integer not less than 2;
• a first data conversion circuit, receiving said input data signal output from said data string number conversion circuit, for converting said input data signal to output the converted input data signal;
• a second data conversion circuit, receiving said input data signal output from said data string number conversion circuit and an output signal of said first data conversion circuit, for converting the received signal into three sets of output signals, termed first, second and third output signals, each being a (p+1) string output signal;
• a parallel-to-serial conversion circuit, receiving said three sets of (p+1) string output signals, output by said second data conversion circuit, for performing time-division multiplexing of said three sets of (p+1) string output signals to output the resulting output signals;
• and
• a multi-level modulating unit, receiving said output signal of said parallel-to-serial conversion circuit to effect multi-level modulation to output the communication signal;
• wherein
• said first data conversion circuit outputs the output signal indicating values from 1 to (7/4)×2p, responsive to the value of said input data signal;
• if the output signal of said first data conversion circuit takes on a value from 1 to 4×2(p−2), said second data conversion circuit sets, based on said input data signal, the value of the output signal of said first data conversion circuit as said first output signal, and outputs signals representing predetermined (7/4)×2p and (7/4)×2p values as said second and third signals, respectively;
• if the output signal of said first data conversion circuit takes on a value from 1+4×2(p−2) to 4×2(p−2)+2×2(p−2), said second data conversion circuit sets the value of the output signal of said first data conversion circuit as said first output signal, and outputs signals representing predetermined (7/4)×2p and 1×2p values as said second and third signals, respectively;
• and
• if the output signal of said first data conversion circuit takes on a value from 1+4×2(p−2)+2×2(p−2) to 4×2(p−2)+2×2(p−2)+1×2(p−2), said second data conversion circuit sets the value of the output signal of said first data conversion circuit as said first output signal and outputs signals representing predetermined 1×2p and (1/2)×2p values as said second and third signals, respectively.

An apparatus for demodulating a communication signal to output a demodulated data signal of (3p+2) strings, where p is an integer not less than 2, said apparatus comprising:

• a multi-level demodulating unit for demodulating said communication signal to output a received demodulated data string signal;
• a parallel-to-serial conversion circuit, receiving and time-division demultiplexing said received demodulated data string signal to output first, second and third demodulated data string signals;
• and
• a data inverse-conversion circuit, receiving said first, second and third demodulated data string signals and outputting said demodulated data signal of 3p+2 strings;
• wherein
• if said first demodulated data string signal takes on a value from 1 to 4×2(p−2), said data inverse-conversion circuit receives signals representing predetermined (7/4)×2p values as second and third demodulated data string signals;
• if said first demodulated data string signal takes on a value from 1+4×2(p−2) to 4×2(p−2)+2×2(p−2), said data inverse-conversion circuit receives signals representing predetermined (7/4)×2p and 1×2p values, as second and third demodulated data string signals, respectively;
• if said first demodulated data string signal takes on a value from 1+4×2(p−2)+2×2(p−2) to 4×2(p−2)+2×2(p−2)+1×2(p−2), said data inverse-conversion circuit receives signals representing predetermined 1×2p and (1/4)×2p values, as second and third demodulated data string signals, respectively, and
• said data inverse-conversion circuit outputs the demodulated data signal of (3p+2) strings, said demodulated data signal taking on a predetermined value, based on the values indicated by said first, second and third demodulated data string signals.

An apparatus for demodulating a communication signal to output a demodulated data signal of (3p+2) strings, where p is an integer not less than 2, said apparatus comprising:

• a multi-level demodulating unit for demodulating said communication signal to output a demodulated received data string signal;
• a serial-to-parallel conversion circuit, receiving and time-division demultiplexing said received demodulated data string signal to output first, second and third demodulated data string signals;
• and
• a data inverse-conversion circuit, receiving said first, second and third demodulated data string signals and outputting said demodulated data signal of (3p+2) strings;
• wherein
• if said first demodulated data string signal takes on a value from 1 to 2) said data inverse-conversion circuit receives signals representing predetermined (7/4)×2p values as second and third demodulated data string signals;
• if said first demodulated data string signal takes on a value from 1+4×2(p−2) to 4×2(p−2)+2×2(p−2), said data inverse-conversion circuit receives signals representing predetermined (7/4)×2p and 1×2p values, as second and third demodulated data string signals, respectively;
• if said first demodulated data string signal takes on a value from 1+4×2(p−2)+2×2(p−2) to 4×2(p−2)+2×2(p−2)+1×2(p−2), said data inverse-conversion circuit receives signals representing predetermined (1/2)×2p and (1/2)×2p values, as second and third demodulated data string signals, respectively, and
• said data inverse-conversion circuit outputs the demodulated data signal of (3p+2) strings, said demodulated data signal taking on a predetermined value, based on the values indicated by said first, second and third demodulated data string signals.

A computer program product causing a computer composing a multi-level modulation apparatus to perform the processing of multi-level modulation of (3p+2) strings of an input data signal, where p is an integer not less than 2;

• said program causing said computer to execute the processing of converting said input data signal into first, second and third conversion data in such a manner that
• said first conversion data takes on a value from 1 to (7/4)×2p depending on the value of said input data signal;
• if said first conversion data takes on a value from 1 to 4×2(p−2), said second and third conversion data takes on predetermined (7/4)×2p values, depending on the value of said input data signal;
• if said first conversion data takes on a value from 1+4×2(p−2) to 4×2(p−2)+2×2(p−2) values, said second and third conversion data takes on predetermined (7/4)×2p and 1×2p values, respectively, depending on the value of said input data signal;
• and
• if said first conversion data takes on a value from 1+4×2(p−2)+2×2(p−2) to 4×2(p−2)+2×2(p−2)+1×2(p−2) values, said second and third conversion data takes on predetermined 1×2p and (1/4)×2p values, respectively, depending on the value of said input data signal;
• said program causing said computer to execute the processing of sequentially outputting said first to third conversion data to a multi-level demodulating unit.

A computer program product causing a computer composing a multi-level demodulation apparatus to perform the processing of multi-level demodulation of a communication signal and outputting a demodulated data signal of (3p+2) strings, where p is an integer not less than 2, said program causing said computer to execute a conversion process which receives said communication signal as demodulated first to third data string signals and converts the received signals into a data demodulated signal of (3p+2) strings;

• said conversion process receiving (7/4)×2p values as said first demodulated data string signals;
• if said first demodulated signal takes on a value from 1 to 4×2(p−2), said conversion process receiving predetermined (7/4)×2p values as said second and third demodulated data string signals, respectively;
• if said first demodulated signal takes on a value from 1+4×2(p−2) to 4×2(p−2)+2×2(p−2), said conversion process receiving predetermined (7/4)×2p and 1×2p values as said second and third demodulated data string signals, respectively;
• if said first demodulated signal takes on a value from 1+4×2(p−2)+2×2(p−2) to 4×2(p−2)+2×2(p−2)+1×1(p−2), said conversion process receiving predetermined 1×2p and (1/4)2p values as said second and third demodulated data string signals, respectively;
• and
• said conversion process outputting a demodulated data signal of (3p+2) strings, said demodulated data signal taking on a predetermined value, based on the values indicated by said first to third demodulated data string signals.

A method of performing multi-level modulating/demodulation in which (3p+2) strings of an input signal are allocated to three modulation symbols, where p is an integer not less than 2, comprising the steps of

• allocating (7/4)×2p signal points as a first modulation symbol;
• if said first modulation symbol takes 1 to 4×2(p−3) signal points, using (7/4)×2p signal points, predetermined in association with said input signal as second and third modulation symbols;
• if said first modulation symbol takes 1+4×2(p−2) to 4×2(p−2)+2×2(p−2) points, using (7/4)×2p and 1×2p signal points, predetermined in association with said input signal, as said second and third modulation symbols, respectively;
• and
• if said first modulation symbol takes 1+4×2(p−2)+2×2(p−2) to 4×2(p−2)+2×2(p−2)+1×2(p−2) signal points, using 1×2p and (1/4)2p signal points, predetermined in association with said input signal, as said second and thirds symbols, respectively.

A method of performing multi-level modulating/demodulation in which (3p+2) strings of an input signal are allocated to three modulation symbols, where p is an integer not less than 2, comprising the steps of

• allocating (7/4)×2p signal points as a first modulation symbol;
• if said first modulation symbol takes 1 to 4×2(p−3) signal points, using (7/4)×2p signal points, predetermined in association with said input signal, as second and third modulation symbol;
• if said first modulation symbol takes 1+4×2(p−2) to 4×2(p−2)+2×2(p−2) signal points, using (7/4)×2p values and 1×2p signal points, predetermined in association with said input signal, as said second and third modulation symbols, respectively;
• and
• if said first modulation symbol takes 1+4×2(p−2)+2×2(p−2) to 4×2(p−2)+2×2(p−2)+1×2(p−2) signal points, using (1/2)×2p values and (t/2)×2p signal points, predetermined in association with said input signal, as said second and third modulation symbols, respectively.

A modulation apparatus comprising:

• converting means receiving an input signal that takes on a value from 1 to a (3p+2) power of 2, where p is an integer not less than 2, to generate and output first to third converted data based on said input signal;
• and
• means, receiving said first to third converted data to effect multi-level modulation thereon to output the resulting data;
• said converting means classifying said input signal, depending on the values thereof, into three predetermined groups not having common elements,
• said converter means including converting means operating such that
• if said input signal belongs to said first group, said first converted data takes on a value form 1 to 4×2(p−2), depending on the value of said input signal, said second and third converted data taking on (7/4)×2p and (7/4)×2p values, allocated depending on the value of said input signal, respectively;
• if said input signal belongs to said second group, said first converted data takes on a value from 1+4×2(p−2) to 4×2(p−2)+2×2(p−2), depending on the value of said input signal, said second and third converted data taking on (7/4)×2p and 1×2p values, allocated depending on the value of said input signal, respectively;
• and
• if said input signal belongs to said third group, said first converted data takes on a value from 1+4×2(p−2)+2×2(p−2) to 4×2(p−2)+2×2(p−2)+1×2(p−2), depending on the value of said input signals, said second and third converted data taking on 1×2p and (1/4)×2p values, allocated depending on the value of said input signal, respectively.

A modulation apparatus comprising:

• converting means receiving an input signal that takes on a value from 1 to a (3p+2) power of 2, where p is an integer not less than 2, to generate and output first to third converted data based on said input signal;
• and
• means receiving said first to third converted data to effect multi-level modulation thereon to output the resulting data;
• said converting means classifying said input signal, depending on the values thereof, into three predetermined groups not having common elements,
• said converter means including means operating such that
• if said input signal belongs to said first group, said first converted data takes on a value form 1 to 4×2(p−2), depending on the value of said input signal, said second and third converted data taking on (7/4)×2p and (7/4)×2p values, allocated depending on the value of said input signal, respectively;
• if said input signal belongs to said second group, said first converted data takes on a value from 1+4×2(p−2) to 4×2(p−2)+2×2(p−2) , depending on the value of said input signal, said second and third converted data taking on (7/4)×2p and 1×2p values, allocated depending on the value of said input signal, respectively;
• and
• if said input signal belongs to said third group, said first converted data takes on a value from 1+4×2(p−2)+2×2(p−2) to 4×2(p−2)+2×2(p−2)+1×2(p−2), depending on the value of said input signal, said second and third converted data taking on (1/2)×2p and (1/2)×2p values, allocated depending on the value of said input signal, respectively.

A method of performing multi-level modulating, said method comprising the steps of:

• converting a data signal of (3p+2) strings, where p is an integer not less than 2, to three signals, each being a (p+1) strings signal and having a predetermined relation to one another;
• allocating the three signals of (p+1) strings separately to three phase planes;
• and
• performing multi-level modulation with the three phase planes as a set, by controlling the numbers of the signal points in the three phase planes;
• wherein an multi-level quadrature amplitude modulation (QAM) is carried out, in which equivalently (p+2/3) bits are allocated to each modulation symbol and the n-ary number is approximated to 2(p+2/3).

An apparatus for performing multi-level modulation of an input data string to output a communication signal, said apparatus comprising:

• a data string number conversion circuit for converting the input data string into an input data signal made up by (4p+3) strings of binary signals, where p is an integer not less than 3, and for outputting said input data signal;
• a first data conversion circuit, receiving the input data signal output from the data string number conversion circuit for converting the input data signal to output the converted input data signal;
• a second data conversion circuit, receiving the input data signal output from the data string number conversion circuit and an output signal of the first data conversion circuit to convert the received signal into four sets of output signals, termed first, second, third and fourth output signals, each being a (p+3) string output signal;
• a parallel-to-serial conversion circuit, receiving and time-division multiplexing the four sets of (p+1) string output signals, output by the second data conversion circuit, to output resulting output signals;
• and
• a multi-level modulating unit, receiving the output signal of the parallel-to-serial conversion circuit, for effecting multi-level modulation to output the communication signal;
• wherein
• the first data conversion circuit outputs the output signal indicating values from 1 to 15×2(p−3), responsive to the value of the input data signal;
• if the output signal of the first data conversion circuit takes on a value from 1 to 8×2(p−3), the second data conversion circuit sets, based on the input data signal, the value of the output signal of the first data conversion circuit as the first output signal and outputs signals representing predetermined 15×2(p−3), 15×2(p−3) and 12×2(p−3) values as the second, third and fourth signals, respectively;
• if the output signal of the first data conversion circuit takes on a value from 8×2(p−3)+1 to 8×2(p−3)+4×2(p−3), the second data conversion circuit sets the value of the output signal of the first data conversion circuit as the first output signal and outputs signals representing predetermined 15×2(p−3), 12×2(p−3) and 12×2(p−3) values as the second, third and fourth output signals, respectively;
• if the output signal of the first data conversion circuit takes on a value from 8×2(p−3)+4×2(p−3)+1 to 8×2(p−3)+4×2(p−3)+2×2(p−3), the second data conversion circuit sets the value of the output signal of the first data conversion circuit as the first output signal and outputs signals representing predetermined 12×2(p−3), 12×2(p−3) and 8×2(p−3) values as the second, third and fourth signals, respectively, and
• if the output signal of the first data conversion circuit takes on a value from 8×2(p−3)+4×2(p−3)+2×2(p−3)+1 to 8×2(p−3)+4×2(p−3)2×2(p−3)+1×2(p−3), said second data conversion circuit sets the value of the output signal of said first data conversion circuit as said first output signal and outputs signals representing predetermined 8×2(p−3), 7×2(p−3) and 4×2(p−3) values as said second, third and fourth signals, respectively.

An apparatus for performing multi-level demodulation of a communication signal to output a demodulated data signal of (4p+3) strings, where p is an integer not less than 3, said apparatus comprising:

• a multi-level demodulating unit for demodulating said communication signals to output a received demodulated data string signal;
• a serial-to-parallel conversion circuit, receiving and time-division demultiplexing said received demodulated data string signal to output first, second, third and fourth demodulated data string signals;
• and
• a data inverse-conversion circuit, receiving said first, second, third and fourth demodulated data string signals to output said demodulated data signal of 4p+3 strings;
• wherein
• if said first demodulated data string signal takes on a value from 1 to 8×2(p−3), said data inverse-conversion circuit receives signals representing predetermined 15×2(p−3), 15×2(p−3) and 12×2(p−3) values as second, third and fourth demodulated data string signals, respectively;
• if said first demodulated data string signal takes on a value from 8×2(p−3)+1 to 8×2(p−3)+4×2(p−3), said data inverse-conversion circuit receives signals representing predetermined 15×2(p−3), 12×2(p−3) and 12×2(p−3) values, as second, third and fourth demodulated data string signals, respectively;
• if said first demodulated data string signal takes on a value from 8×2(p−3)+4×2(p−3)+1 to 8×2(p−3)+4×2(p−3)+2×2(p−3), said data inverse-conversion circuit receives signals representing predetermined 12×2(p−3), 12×2(p−3) and 8×2(p−3) values, as second, third and fourth demodulated data string signals, respectively;
• if said first demodulated data string signal takes on a value from 8×2(p−3)+4×2(p−3)+2×2(p−3)+1 to 8×2(p−3)+4×2(p−3)+2×2(p−3)+1×2(p−3), said data inverse-conversion circuit receives signals representing predetermined 8×2(p−3), 7×2(p−3) and 4×2(p−3) values, as second, third and fourth demodulated data string signals, respectively;
• and
• said data inverse-conversion circuit outputs the demodulated data taking on a predetermined value, based on the values indicated by said first, second, third and fourth demodulated data string signals, as said (4p+3) strings of said demodulated data.

A computer program product causing computer composing a multi-level modulation apparatus to perform the processing of multi-level modulation of (4p+3) strings of an input data signal, where p is an integer not less than 3;

• said program causing said computer to execute the processing of converting said input data signal into first, second, third and fourth converted data in such a manner that
• said first conversion data takes on a value from 1 to 15×2(p−3) depending on the value of said input data signal;
• if said first conversion data takes on a value from 1 to 8×2(p−3), said second, third and fourth conversion data take on predetermined 15×2(p−3), 12×2(p−3) and 12×2(p−3) values, depending on the value of said input data signal, respectively;
• if said first conversion data takes on a value from to 8×2(p−3)+1 to 8×2(p−3)+4×2(p−3) values, said second, third and fourth conversion data take on predetermined 15×2(p−3) and values, respectively, depending on the value of said input data signal;
• if said first conversion data takes on a value from 8×2(p−3)+4×2(p−3)+1 to 8×2(p−3)+4×2(p−3)+2×2(p−3) values, said second, third and fourth conversion data take on predetermined 12×2(p−3) and 8×2(p−3) values, respectively, depending on the value of said input data signal;
• and
• if said first conversion data takes on a value from 8×2(p−3)+4×2(p−3)+2×2(p−3)+1 to 8×2(p−3)+4×2(p−3)+2×2(p−3)1×2(p−3) values, said second, third and fourth conversion data take on predetermined 8×2(p−3)+7×2(p−3) and 4×2(p−3) values, respectively, depending on the value of said input data signal;
• said program causing said computer to execute the processing of sequentially outputting said first to fourth conversion data to a multi-level demodulating unit.

A computer program product causing a computer composing a multi-level demodulation apparatus to perform a processing of multi-level demodulation of a communication signal and outputting a demodulated data signal of (4p+3) strings, where p is an integer not less than 3, said program causing said computer to execute a conversion process which receives said communication signal as demodulated first to fourth data string signals and converts the received signals into a data demodulated signal of (4p+3) strings;

• said conversion process receiving 15×2(p−3) values as said first demodulated data string signal;
• if said first demodulated signal takes on a value from 1 to 8×2(p−3), predetermined 15×2(p−3), said conversion process receiving 15×2(p−3) and 12×2(p−3) values are received as said second, third and fourth demodulated data string signals, respectively;
• if said first demodulated signal takes on a value from 8×2(p−3)+1 to 8×2(p−3) to 4×2(p−3) said conversion process receiving predetermined 15×2(p−3), 12×2(p−3) and 12×2(p−3) values as said second, third and fourth demodulated data string signals, respectively;
• if said first demodulated signal takes on a value from 8×2(p−3) to 4×2(p−3)+1 to 8×2(p−3) to 4×2(p−3)+2×2(p−3), said conversion process receiving predetermined 15×2(p−3), 15×2(p−3) and 12×2(p−3) values as said second, third and fourth demodulated data string signals, respectively;
• if said first demodulated signal takes on a value from 8×2(p−3) to 4×2(p−3)+2×2(p−2)+1 to 8×2(p−2) to 4×2(p−2)+2×2(p−2)1×2(p−2), predetermined 8×2(p−3), said conversion process receiving 7×2(p−3) and 4×2(p−3) values are received as said second, third and fourth demodulated data string signals, respectively,
• said conversion process outputting a demodulated data signal of (4p+3) strings, said demodulated data signal taking on a predetermined value, based on the values indicated by said first to fourth demodulated data string signals.

A method of performing multi-level modulating/demodulation in which (4p+1) strings of an input signal are allocated to three modulation symbols, where p is an integer not less than 3, comprising the steps of:

• allocating 15×2(p−3) signal points as a first modulation symbol;
• if said first modulation symbol takes 1 to 8×2(p−3) signal points, using 1×2(p−3), 12×2(p−3) and 12×2(p−3) signal points, predetermined in association with said input signal, as second, third and fourth modulation symbols;
• if said first modulation symbol takes 8×2(p−3)+1 to 8×2(p−3)+4×2(p−3) signal points, using 15×2(p−3), 15×2(p−3) and 12×2(p−3) signal point predetermined in association with said input signal, are used as said second, third and fourth modulation symbols respectively;
• if said first modulation symbol takes 8×2(p−3)+4×2(p−3)+1 to 8×2(p−3)+4×2(p−3)+2×2(p−3) signal points, using 12×2(p−3), 12×2(p−3) and 8×2(p−3) signal points, predetermined in association with said input signal, are used as said second, third and fourth modulation symbols, respectively;
• and
• if said first modulation symbol takes 8×2(p−3)+4×2(p−3)+2×2(p−3)+1 to 8×2(p−3)+4×2(p−3)+2×2(p−3)+1×2(p−3) signal points, using 8×2(p−3), 7×2(p−3) and 4×2(p−3) signal points, predetermined in association with said input signal, are used as said second, third and fourth modulation symbols, respectively.

A modulation apparatus comprising

• converting means, receiving an input signal that takes on a value from 1 to a (4p+3) power of 2, where p is an integer not less than 3, to generate and output first to fourth conversion data based on said input signal;
• and
• means, receiving said first to fourth converted data to effect multi-level modulation thereon to output the resulting data;
• said converting means classifying said input signal, depending on the values thereof, into four predetermined groups not having common elements;
• said converter means having means for executing conversion such that
• if said input signal belongs to said first group, said first conversion data takes on a value form 1 to 8×2(p−3), depending on the value of said input signal, said second, third and fourth converted data taking on 15×2(p−3), 15×2(p−3) and 12×2(p−3) values, allocated depending on the value of said input signal, respectively;
• if said input signal belongs to said second group, said first conversion data takes on a value from 8×2(p−3)+1 to 8×2(p−3)+4×2(p−3), depending on the value of said input signal, said second, third and fourth conversion data taking on 15×2(p−3), 15×2(p−3) and 12×2(p−3) values, allocated depending on the value of said input signal, respectively;
• if said input signal belongs to said third group, said first conversion data takes on a value from 8×2(p−3)++4×2(p−3)+1 to 8×2(p−3)+4×2(p−3)+2×2(p−3) depending on the value of said input signal, said second, third and fourth conversion data taking on 12×2(p−3), 12×2(p−3) and 8×2(p−3) values, allocated depending on the value of said input signal, respectively;
• and
• if said input signal belongs to said third group, said first conversion data takes on a value from 8×2(p−3)+4×2(p−3)+2×2(p−3)+1 to 8×2(p−3)+4×2(p−3)+2×2(p−3)+1×2(p−3) depending on the value signal, said second, third and fourth converted data taking on 8×2(p−3), 7×2(p−3) and 4×2(p−3) values, allocated depending on the value of said input signal, respectively.

A method of performing modulation comprising the steps of:

• converting a data signal of (4p+3) strings, where p is an integer not less than 3, to four signals, each being a (p+1) string and having a predetermined relation to one another,
• allocating the four signal of (p+1) string separately to four phase planes, and
• performing multi-level modulation, with the four phase planes as a set, by controlling respective numbers of signal points in the four phase planes;
• wherein an multi-level quadrature amplitude modulation (QAM) is carried out, in which equivalently (p+3/4) bits are allocated to each modulation symbol and the n-ary number is approximated to 2(p−3/4).