Signal generation method and signal generation device

1. An OFDM signal generation method of a transmission system, the transmission system having a first transmitter and a second transmitter, the OFDM signal generating method comprising:

modulating, by the first transmitter, each of a plurality of coded blocks to a first modulated signal s 1 , the coded blocks each made up of a plurality of bits by using a determined error correction block coding scheme;

modulating, by the second transmitter, each of the coded blocks to a second modulated signal s 2 , data included in the first modulated signal s 1 being same as data included in the second modulated signal s 2 ;

inserting, by the first transmitter, one or more pilots to the first modulated signal s 1 to obtain a first pilot-inserted signal s 1 ′;

inserting, by the second transmitter, the one or more pilots to the second modulated signal s 2 to obtain a second pilot-inserted signal s 2 ;

phase-changing, by the first transmitter, while regularly varying a first scheme of phase change for each of a plurality of slots, the first pilot-inserted signal s 1 ′ to obtain a first transmission signal z 1 ;

phase-changing, by the second transmitter, while regularly varying a second scheme of phase change for each of the plurality of slots, the second pilot-inserted signal s 2 ′ to obtain a second transmission signal z 2 ;

converting, by the first transmitter, the first transmission signal z 1 to a first OFDM signal;

converting, by the second transmitter, the second transmission signal z 2 to a second OFDM signal;

inserting, by the first transmitter, a part of the first OFDM signal to the first OFDM signal to be transmitted from a first antenna at a first period at a first frequency; and

inserting, by the second transmitter, a part of the second OFDM signal to the second OFDM signal to be transmitted from a second antenna at the first period at the first frequency.

2. An OFDM signal generation system comprising:

a first OFDM signal generator; and

a second OFDM signal generator,

wherein the first OFDM signal generator, in operation,

modulates each of a plurality of coded blocks to a first modulated signal s 1 , the coded blocks each made up of a plurality of bits by using a determined error correction block coding scheme;

inserts one or more pilots to the first modulated signal s 1 to obtain a first pilot-inserted signal s 1 ′;

phase-changes, while regularly varying a first scheme of phase change for each of a plurality of slots, the first pilot-inserted signal s 1 ′ to obtain a first transmission signal z 1 ;

converts the first transmission signal z 1 to a first OFDM signal;

inserts a part of the first OFDM signal to the first OFDM signal to be transmitted from a first antenna at a first period at a first frequency; and

wherein the second OFDM signal generator, in operation,

modulates each of the coded blocks to a second modulated signal s 2 , data included in the first modulated signal s 1 being same as data included in the second modulated signal s 2 ;

inserts the one or more pilots to the second modulated signal s 2 to obtain a second pilot-inserted signal s 2 ;

phase-changes, while regularly varying a second scheme of phase change for each of the plurality of slots, the second pilot-inserted signal s 2 ′ to obtain a second transmission signal z 2 ;

converts the second transmission signal z 2 to a second OFDM signal; and

inserts a part of the second OFDM signal to the second OFDM signal to be transmitted from a second antenna at the first period at the first frequency.

3. A reception data generation method of a reception apparatus, the method comprising:

acquiring a reception signal obtained by converting a first OFDM signal transmitted from a first antenna of a first transmitter at a first period at a first frequency and a second OFDM signal transmitted from a second antenna of a second transmitter at the first period at the first frequency, the first OFDM signal and the second OFDM signal having been generated through a determined generation process; and

demodulating the reception signal to reception data, through a demodulation process corresponding to the determined generation process, wherein

at least one of the acquiring and the demodulating is performed by the reception apparatus, and

the determined generation process is a process of:

modulating, by the first transmitter, each of a plurality of coded blocks to a first modulated signal s 1 , the coded blocks each made up of a plurality of bits by using a determined error correction block coding scheme;

modulating, by the second transmitter, each of the coded blocks to a second modulated signal s 2 , data included in the first modulated signal s 1 being same as data included in the second modulated signal s 2 ;

inserting, by the first transmitter, one or more pilots to the first modulated signal s 1 to obtain a first pilot-inserted signal s 1 ′;

inserting, by the second transmitter, the one or more pilots to the second modulated signal s 2 to obtain a second pilot-inserted signal s 2 ′;

phase-changing, by the first transmitter, while regularly varying a first scheme of phase change for each of a plurality of slots, the first pilot-inserted signal s 1 ′ to obtain a first transmission signal z 1 ;

phase-changing, by the second transmitter, while regularly varying a second scheme of phase change for each of the plurality of slots, the second pilot-inserted signal s 2 ′ to obtain a second transmission signal z 2 ;

converting, by the first transmitter, the first transmission signal z 1 to the first OFDM signal;

converting, by the second transmitter, the second transmission signal z 2 to the second OFDM signal;

inserting, by the first transmitter, a part of the first OFDM signal to the first OFDM signal to be transmitted from the first antenna at the first period at the first frequency; and

inserting, by the second transmitter, a part of the second OFDM signal to the second OFDM signal to be transmitted from the second antenna at the first period at the first frequency.

4. A reception data generation apparatus comprising:

a memory; and

control circuitry,

wherein the control circuitry, in operation, performs the steps of:

acquiring a reception signal obtained by converting a first OFDM signal transmitted from a first antenna of a first transmitter at a first period at a first frequency and a second OFDM signal transmitted from a second antenna of a second transmitter at the first period at the first frequency, the first OFDM signal and the second OFDM signal having been generated through a determined generation process; and

demodulating the reception signal to reception data, through a demodulation process corresponding to the determined generation process, wherein

at least one of the acquiring and the demodulating is performed by the control circuitry, and

the determined generation process is a process of:

modulating, by the first transmitter, each of a plurality of coded blocks to a first modulated signal s 1 , the coded blocks each made up of a plurality of bits by using a determined error correction block coding scheme;

modulating, by the second transmitter, each of the coded blocks to a second modulated signal s 2 , data included in the first modulated signal s 1 being same as data included in the second modulated signal s 2 ;

inserting, by the first transmitter, one or more pilots to the first modulated signal s 1 to obtain a first pilot-inserted signal s 1 ′;

inserting, by the second transmitter, the one or more pilots to the second modulated signal s 2 to obtain a second pilot-inserted signal s 2 ′;

phase-changing, by the first transmitter, while regularly varying a first scheme of phase change for each of a plurality of slots, the first pilot-inserted signal s 1 ′ to obtain a first transmission signal z 1 ;

phase-changing, by the second transmitter, while regularly varying a second scheme of phase change for each of the plurality of slots, the second pilot-inserted signal s 2 ′ to obtain a second transmission signal z 2 ;

converting, by the first transmitter, the first transmission signal z 1 to the first OFDM signal;

converting, by the second transmitter, the second transmission signal z 2 to the second OFDM signal;

inserting, by the first transmitter, a part of the first OFDM signal to the first OFDM signal to be transmitted from the first antenna at the first period at the first frequency; and

inserting, by the second transmitter, a part of the second OFDM signal to the second OFDM signal to be transmitted from the second antenna at the first period at the first frequency.