Signal generation method and signal generation device
A transmission method simultaneously transmitting a first modulated signal and a second modulated signal at a common frequency performs precoding on both signals using a fixed precoding matrix and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception 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:
mapping, by the first transmitter, one or more coded blocks to a first mapped signal s 1 , the one or more coded blocks generated by using a determined error correction block coding scheme;
mapping, by the second transmitter, the one or more coded blocks to a second mapped signal s 2 , data included in the first mapped signal s 1 being same as data included in the second mapped signal s 2 ;
inserting, by the first transmitter, one or more pilots to the first mapped signal s 1 to obtain a first pilot-inserted signal sp 1 ;
inserting, by the second transmitter, the one or more pilots to the second mapped signal s 2 to obtain a second pilot-inserted signal sp 2 ;
phase-changing, by the first transmitter, the first pilot-inserted signal sp 1 for each of a plurality of slots to obtain a first transmission signal z 1 by using a first scheme of a regularly varying phase change process;
phase-changing, by the second transmitter, the second pilot-inserted signal sp 2 for each of the plurality of slots to obtain a second transmission signal z 2 by using a second scheme of the regularly varying phase change process;
converting, by the first transmitter, the first transmission signal z 1 for each of the plurality of slots to a first OFDM signal for each of a plurality of subcarriers;
converting, by the second transmitter, the second transmission signal z 2 for each of the plurality of slots to a second OFDM signal for each of the plurality of subcarriers;
inserting, by the first transmitter, one or more first symbols to enable synchronization 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, one or more second symbols to enable synchronization 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 generating circuit; and
a second OFDM signal generating circuit,
wherein the first OFDM signal generating circuit, in operation,
maps one or more coded blocks to a first mapped signal s 1 , the one or more coded blocks generated by using a determined error correction block coding scheme;
inserts one or more pilots to the first mapped signal s 1 to obtain a first pilot-inserted signal sp 1 ;
phase-changes, while regularly varying a first scheme of phase change for each of a plurality of slots, the first pilot-inserted signal sp 1 for each of the plurality of slots to obtain a first transmission signal z 1 ;
converts the first transmission signal z 1 for each of the plurality of slots to a first OFDM signal for each of a plurality of subcarriers;
inserts one or more first symbols to enable synchronization 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 generating circuit, in operation,
maps the one or more coded blocks to a second mapped signal s 2 , data included in the first mapped signal s 1 being same as data included in the second mapped signal s 2 ;
inserts the one or more pilots to the second mapped signal s 2 to obtain a second pilot-inserted signal sp 2 ;
phase-changes the second pilot-inserted signal sp 2 for each of the plurality of slots to obtain a second transmission signal z 2 by using a second scheme of the regularly varying phase change process;
converts the second transmission signal z 2 for each of the plurality of slots to a second OFDM signal for each of the plurality of subcarriers; and
inserts one or more second symbols to enable synchronization 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 by using one or more first symbols to enable synchronization and one or more second symbols to enable synchronization, the first OFDM signal and the second OFDM signal having been generated through a determined generation process; and
de-mapping the reception signal to reception data, through a de-map process corresponding to the determined generation process, wherein
the determined generation process is a process of:
mapping, by the first transmitter, one or more coded blocks to a first mapped signal s 1 , the one or more coded blocks generated by using a determined error correction block coding scheme;
mapping, by the second transmitter, the one or more coded blocks to a second mapped signal s 2 , data included in the first mapped signal s 1 being same as data included in the second mapped signal s 2 ;
inserting, by the first transmitter, one or more pilots to the first mapped signal s 1 to obtain a first pilot-inserted signal sp 1 ;
inserting, by the second transmitter, the one or more pilots to the second mapped signal s 2 to obtain a second pilot-inserted signal sp 2 ;
phase-changing, by the first transmitter, the first pilot-inserted signal sp 1 for each of the plurality of slots to obtain a first transmission signal z 1 by using a first scheme of a regularly varying phase change process;
phase-changing, by the second transmitter, the second pilot-inserted signal sp 2 for each of the plurality of slots to obtain a second transmission signal z 2 by using a first scheme of the regularly varying phase change process;
converting, by the first transmitter, the first transmission signal z 1 for each of the plurality of slots to the first OFDM signal for each of a plurality of subcarriers;
converting, by the second transmitter, the second transmission signal z 2 for each of the plurality of slots to the second OFDM signal for each of the plurality of subcarriers;
inserting, by the first transmitter, the one or more first symbols to enable synchronization 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, the one or more second symbols to enable synchronization 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 by using one or more first symbols to enable synchronization and one or more second symbols to enable synchronization, the first OFDM signal and the second OFDM signal having been generated through a determined generation process; and
de-mapping the reception signal to reception data, through a de-map process corresponding to the determined generation process, wherein
the determined generation process is a process of:
mapping, by the first transmitter, one or more coded blocks to a first mapped signal s 1 , the one or more coded blocks generated by using a determined error correction block coding scheme;
mapping, by the second transmitter, the one or more coded blocks to a second mapped signal s 2 , data included in the first mapped signal s 1 being same as data included in the second mapped signal s 2 ;
inserting, by the first transmitter, one or more pilots to the first mapped signal s 1 to obtain a first pilot-inserted signal sp 1 ;
inserting, by the second transmitter, the one or more pilots to the second mapped signal s 2 to obtain a second pilot-inserted signal sp 2 ;
phase-changing, by the first transmitter, the first pilot-inserted signal sp 1 for each of the plurality of slots to obtain a first transmission signal z 1 by using a first scheme of a regularly varying phase change process;
regularly phase-changing, by the second transmitter, the second pilot-inserted signal sp 2 for each of the plurality of slots to obtain a second transmission signal z 2 by using a second scheme of the regularly varying phase change process;
converting, by the first transmitter, the first transmission signal z 1 for each of the plurality of slots to the first OFDM signal for each of a plurality of subcarriers;
converting, by the second transmitter, the second transmission signal z 2 for each of the plurality of slots to the second OFDM signal for each of the plurality of subcarriers;
inserting, by the first transmitter, the one or more first symbols to enable synchronization 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, the one or more second symbols to enable synchronization to the second OFDM signal to be transmitted from the second antenna at the first period at the first frequency.