Transmitter, receiver, transmitting method, and receiving method

A transmitter comprising:

• a mapping circuit configured to combine and map a first data sequence and a second data sequence onto orthogonal frequency division multiplexing (OFDM) subcarriers which include first subcarriers and second subcarriers;
• and
• a framing circuit configured to generate an OFDM signal from the OFDM subcarriers, wherein
• the mapping circuit is configured to:
• map first data included in the first data sequence and second data included in the second data sequence onto the first subcarriers;
• and
• map the second data onto the second subcarriers, the first data being not mapped on the second subcarriers, and
• the transmitter further comprises:
• an interleaving circuit configured to interleave data that are to be mapped onto the OFDM subcarriers, wherein
• the interleaving circuit:
• switches data mapped onto one first subcarrier with data mapped onto another first subcarrier, the one first subcarrier and the another first subcarrier being included in the first subcarriers, the data mapped onto the one first subcarrier and the data mapped onto the another first subcarrier including the first data and the second data;
• and
• switches data mapped onto one second subcarrier with data mapped onto another second subcarrier, the one second subcarrier and the another second subcarrier being included in the second subcarriers, the data mapped onto the one second subcarrier with the data mapped onto the another second subcarrier does not include the first data, and
• the first data and the second data remain mapped onto each of the first subcarriers after switching.