Radio transmission apparatus, radio reception apparatus, and radio transmission method

A radio receiving apparatus that receives and demodulates an OFDM-CDMA signal from a radio transmitting apparatus that comprises:

• a spreading section that spreads a plurality of transmit signals using different spreading codes;
• an orthogonal frequency division multiplexing section that assigns a spread plurality of transmit signals to a plurality of subcarriers;
• a signal multiplexing degree selecting section that selects on a subcarrier-by-subcarrier basis a degree of multiplexing of said transmit signals transmitted by subcarriers;
• and
• a multiplex signal allocation selecting section that selects multiplex transmit signals to be allocated to subcarriers;
• and that selects, by means of said multiplex signal allocation selecting section, subcarriers to which a multiplex signal with a low degree of multiplexing is allocated according to a cell to which a communicating party belongs;
• said radio receiving apparatus comprising:
• an orthogonal conversion section that executes orthogonal conversion processing on a received signal;
• a multiplex signal discrimination section that divides a signal that has undergone orthogonal conversion into a multiplex signal with a low degree of multiplexing and a multiplex signal with a high degree of multiplexing;
• and
• an identifying section that identifies a cell to which a station itself belongs by discriminating subcarriers to which a multiplex signal with a low degree of multiplexing is assigned.

A radio receiving apparatus that receives and demodulates an OFDM-CDMA signal from a radio transmitting apparatus that comprises:

• a spreading section that spreads a plurality of transmit signals using different spreading codes;
• an orthogonal frequency division multiplexing section that assigns a spread plurality of transmit signals to a plurality of subcarriers;
• and
• a signal multiplexing degree selecting section that selects on a subcarrier-by-subcarrier basis a degree of multiplexing of said transmit signals transmitted by subcarriers;
• and that makes at least one of a plurality of transmit signals a known signal, and changes a type or spreading code of that known signal at transmit frame start timing;
• said radio receiving apparatus comprising:
• an orthogonal conversion section that executes orthogonal conversion processing on a received signal;
• a multiplex signal discrimination section that divides a signal that has undergone orthogonal conversion into a multiplex signal with a low degree of multiplexing and a multiplex signal with a high degree of multiplexing;
• and
• a frame synchronization signal detecting section that obtains a frame synchronization signal by finding maximum value detection timing of a correlation value between a multiplex signal with a low degree of multiplexing and a known signal or spreading code.

A radio receiving apparatus that receives and demodulates an OFDM-CDMA signal transmitted from a radio transmitting apparatus that comprises:

• a spreading section that spreads a plurality of transmit signals using different spreading codes;
• an orthogonal frequency division multiplexing section that assigns a spread plurality of transmit signals to a plurality of subcarriers;
• a signal multiplexing degree selecting section that selects on a subcarrier-by-subcarrier basis a degree of multiplexing of said transmit signals transmitted by subcarriers;
• and
• a multiplex signal allocation selecting section that allocates a multiplex signal with a low degree of signal multiplexing, selected by said signal multiplexing degree selecting section, to a plurality of subcarrier groups;
• said radio receiving apparatus comprising:
• an orthogonal conversion section that executes orthogonal conversion processing on a received signal;
• a multiplex signal discrimination section that divides a signal that has undergone orthogonal conversion into a multiplex signal with a low degree of multiplexing and a multiplex signal with a high degree of multiplexing;
• a combining section that combines multiplex signals with a low degree of multiplexing;
• and
• a despreading section that extracts a predetermined signal from multiplexed signals by despreading a signal after combining using a predetermined spreading code.

A radio transmitting method comprising:

• a spreading step of spreading a plurality of transmit signals using different spreading codes;
• an orthogonal frequency division multiplexing step of assigning spread signals to a plurality of subcarriers that are in a mutually orthogonal relationship;
• and
• a signal multiplexing degree selecting step of selecting on a subcarrier-by-subcarrier basis a degree of multiplexing of transmit signals transmitted by subcarriers.