Communication method, and transmitting apparatus and receiving apparatus using that communication method
A method for generating a transmission signal to transmit an orthogonal frequency division multiplexing signal, from one antenna or from a plurality of antennas, to a plurality of terminals. Transmission data for the plurality of terminals is assigned to a plurality of carrier groups, each carrier group including a plurality of carriers. For each of the plurality of carrier groups, one of a first frame configuration is selected, wherein one modulated signal is transmitted, and a second frame configuration is selected wherein a plurality of modulated signals are transmitted by using the plurality of antennas. A transmission signal is generated using the selected frame configuration, for transmitting the transmission data assigned to the plurality of carrier groups during a certain period.
1. A method for generating a transmission signal to transmit an orthogonal frequency division multiplexing signal, from one antenna or from a plurality of antennas, to a plurality of terminals, the method comprising:
assigning transmission data for the plurality of terminals to a plurality of carrier groups, each carrier group including a plurality of carriers;
selecting, for each of the plurality of carrier groups, one of a first frame configuration wherein one modulated signal is transmitted and a second frame configuration wherein a plurality of modulated signals are transmitted by using the plurality of antennas; and
generating a transmission signal using the selected frame configuration, for transmitting the transmission data assigned to the plurality of carrier groups during a certain period.
2. The method according to claim 1 , wherein the selection of the frame configuration is performed based on signal propagation environment information that is fed back from a terminal of a communicating party.
3. The method according to claim 2 , wherein the signal propagation environment information comprises received signal strength information.
4. The method according to claim 2 , wherein the signal propagation environment information comprises channel state information.
5. The method according to claim 1 , wherein the modulated signal comprises:
a data symbol for transmitting transmission data to one of the plurality of terminals; and
a control symbol that is allocated ahead of the data symbol on a time axis, and that is usable by a terminal which receives the modulated signal in order to estimate the transmission data.
6. The method according to claim 1 , wherein the modulated signal comprises:
a data symbol for transmitting transmission data to one of the plurality of terminals; and
an estimation symbol that is allocated ahead of the data symbol on a time axis for estimating one of time synchronization, frequency offset and propagation path distortion.
7. The method according to claim 1 , wherein, in the second frame configuration, the plurality of modulated signals are transmitted over an identical frequency band by using the plurality of antennas.
8. A method for generating a transmission signal to transmit an orthogonal frequency division multiplexing signal, from one antenna or from a plurality of antennas, to a plurality of terminals, the method comprising:
configuring a transmission frame including a first carrier group where transmission data for a first terminal is assigned and a second carrier group where transmission data for a second terminal is assigned, each of the first carrier group and the second carrier group including a plurality of carriers;
selecting, for the first carrier group, one of a first frame configuration wherein one modulated signal is transmitted and a second frame configuration wherein a plurality of modulated signals are transmitted by using the plurality of antennas;
selecting, for the second carrier group, one of the first frame configuration and the second frame configuration; and
generating a transmission signal using the selected frame configuration, for transmitting the transmission data assigned to the plurality of carrier groups during a certain period.
9. The method according to claim 8 , wherein:
during a first period, the transmission data for the first terminal is transmitted by using the first carrier group and the transmission data for the second terminal is transmitted by using the second carrier group; and
during a second period, the transmission data for a third terminal is transmitted by using the first carrier group and the transmission data for a fourth terminal is transmitted by using the second carrier group.
10. The method according to claim 8 , wherein, in the second frame configuration, the plurality of modulated signals are transmitted over an identical frequency band by using the plurality of antennas.
11. An apparatus for generating a transmission signal to transmit an orthogonal frequency division multiplexing signal, from one antenna or from a plurality of antennas, to a plurality of terminals, the apparatus comprising:
a frame configuration selector that assigns transmission data for the plurality of terminals to a plurality of carrier groups, each carrier group including a plurality of carriers, and selects, for each of the plurality of carrier groups, one of a first frame configuration wherein one modulated signal is transmitted and a second frame configuration wherein a plurality of modulated signals are transmitted by using the plurality of antennas; and
a transmission signal generator that generates a transmission signal using the selected frame configuration, for transmitting the transmission data assigned to the plurality of carrier groups during a certain period.
12. The apparatus according to claim 11 , wherein the frame configuration selector selects one of the first frame configuration and second frame configuration, based on signal propagation environment information that is fed back from a terminal of a communicating party.
13. The apparatus according to claim 12 , wherein the signal propagation environment information comprises received signal strength information.
14. The apparatus according to claim 12 , wherein the signal propagation environment information comprises channel state information.
15. The apparatus according to claim 11 , wherein the modulated signal comprises:
a data symbol for transmitting transmission data to one of the plurality of terminals; and
a control symbol that is allocated ahead of the data symbol on a time axis, and that is usable by a terminal which receives the modulated signal in order to estimate the transmission data.
16. The apparatus according to claim 11 , wherein the modulated signal comprises:
a data symbol for transmitting transmission data to one of the plurality of terminals; and
an estimation symbol that is allocated ahead of the data symbol on a time axis for estimating one of time synchronization, frequency offset and propagation path distortion.
17. The apparatus according to claim 11 , wherein, in the second frame configuration, the plurality of modulated signals are transmitted over an identical frequency band by using the plurality of antennas.
18. An apparatus for generating a transmission signal to transmit an orthogonal frequency division multiplexing signal, from one antenna or from a plurality of antennas, to a plurality of terminals, the apparatus comprising:
a frame configuration selector that:
configures a transmission frame including a first carrier group where transmission data for a first terminal is assigned and a second carrier group where transmission data for a second terminal is assigned, each of the first carrier group and the second carrier group including a plurality of carriers,
selects, for the first carrier group, one of a first frame configuration wherein one modulated signal is transmitted and a second frame configuration wherein a plurality of modulated signals are transmitted by using the plurality of antennas, and
selects, for the second carrier group, one of the first frame configuration and the second frame configuration; and
a transmission signal generator that generates a transmission signal using the selected frame configuration, for transmitting the transmission data assigned to the plurality of carrier groups during a certain period.
19. The apparatus according to claim 18 , wherein:
during a first period, the transmission data for the first terminal is transmitted by using the first carrier group and the transmission data for the second terminal is transmitted by using the second carrier group; and
during a second period, the transmission data for a third terminal is transmitted by using the first carrier group and the transmission data for a fourth terminal is transmitted by using the second carrier group.
20. The apparatus according to claim 18 , wherein, in the second frame configuration, the plurality of modulated signals are transmitted over an identical frequency band by using the plurality of antennas.