Transmission device, reception device, and radio communication method

A communications apparatus comprising:

• a first spreading section configured to generate a first spread signal by spreading using a first spreading code that has a first spectrum spreading ratio;
• a second spreading section configured to generate a second spread spectrum signal by spreading using a second spreading code that has a second spreading ratio different from the first spreading ratio;
• and
• a multiplexing section configured to generate a multiplex signal by multiplexing the first and second spread spectrum signals in a same frequency band.

A communications apparatus comprising:

• a first Orthogonal Frequency-Division Multiplexing (OFDM)-spreading section configured to generate a first OFDM-spread spectrum signal by spreading using a first spreading code that has a first spreading ratio;
• a second OFDM-spreading section configured to generate a second OFDM-spread spectrum signal by spreading using a second spreading code that has a second spreading ratio different from the first spreading ratio;
• a multiplexing section configured to generate a multiplex signal by multiplexing the first and second OFDM-spread spectrum signals in a same frequency band;
• and
• a transmission section configured to wirelessly transmit the multiplex signal.

A communications apparatus comprising:

• a reception section configured to receive a multiplex signal in which are multiplexed first and second spread spectrum signals generated using first and second spreading codes with different spreading ratios;
• a first demodulation section configured to separate and demodulate the first spread spectrum signal from the received multiplex signal;
• a regeneration section configured to generate a replica signal of the first spread spectrum signal;
• a signal extraction section configured to extract the second spread spectrum signal from the received multiplex signal based upon the replica signal;
• and
• a second demodulation section configured to demodulate the extracted second spread spectrum signal.

A communications method comprising:

• generating, at a first spreading section, a first spread spectrum signal by spreading using a first spreading code that has a first spreading ratio;
• generating, at a second spreading section, a second spread spectrum signal by spreading using a second spreading code that has a second spreading ratio different from the first spreading ratio;
• and
• generating, at a multiplexing section, a multiplex signal by multiplexing the first and second spread spectrum signals in a same frequency band.

A communications method comprising:

• receiving, at a reception section, a multiplex signal in which are multiplexed first and second spread spectrum signals generated using first and second spreading codes with different spreading ratios;
• separating and demodulating, at a first demodulation section, the first spread spectrum signal from the received multiplex signal;
• generating, at a regeneration section, a replica signal of the first spread spectrum signal;
• extracting, at a signal extraction section, the second spread spectrum signal from the received multiplex signal based upon the replica signal;
• and
• demodulating, at a second demodulation section, the extracted second spread spectrum signal.