Wireless transmission device and wireless transmission method
View Patent ↗A wireless transmission device of the present invention includes n (where n is an integer of two or more) transmission antennas and a delay imparting section for delaying transmission signals supplied to the n transmission antennas by a maximum delay time (n−1)T or less based on a delay time T dependent upon a communication signal, which indicates whether to transmit the transmission signals by way of frequency diversity or multiuser diversity.
1. A transmission control method adapted to a transmission system in which slots are assigned to chunks divided in a frequency domain and in a time domain,
said transmission control method comprising the steps of:
imparting delays to signals being supplied to a plurality of transmission antennas;
and
controlling the delays in response to using either a frequency diversity for transmitting the signals or a multiuser diversity for transmitting the signals such that a maximum delay time among the plurality of transmission antennas is set selectively to either a first value smaller than 1/Fc or a second value larger than 1/Fc where Fc denotes a frequency band width of each chunk.
2. The transmission control method according to claim 1 ,
wherein a directivity control is performed in the multiuser diversity for transmitting the signals.
3. The transmission control method according to claim 1 ,
wherein the maximum delay time among the plurality of transmission antennas is set to the first value smaller than 1/Fc when using frequency diversity for transmitting the signals, and
wherein the maximum delay time among the plurality of transmission antennas is set to the second value larger than 1/Fc when using multiuser diversity for transmitting the signals.
4. The transmission control method according to claim 1 ,
wherein the maximum delay time among the plurality of transmission antennas is set to the first value smaller than 1/Fc when using frequency diversity for transmitting the signals.
5. The transmission control method according to claim 1 ,
wherein the maximum delay time among the plurality of transmission antennas is set to the second value larger than 1/Fc when using multiuser diversity for transmitting the signals.
6. A transmission control method adapted to a transmission system in which slots are assigned to chunks divided in a frequency domain and in a time domain,
said transmission control method comprising the steps of:
determining whether to transmit signals using either frequency diversity or multiuser diversity based on a selection between using frequency diversity and multiuser diversity; and
controlling delays supplied to a plurality of transmission antennas in response to the determination of using either a frequency diversity for transmitting the signals or a multiuser diversity for transmitting the signals such that a maximum delay time among a plurality of transmission antennas is set selectively to either a first value smaller than 1/Fc or a second value larger than 1/Fc where Fc denotes a frequency bandwidth of each chunk.
7. The transmission control method according to claim 6 ,
wherein a directivity control is performed in the multiuser diversity for transmitting the signals.
8. The transmission control method according to claim 6 ,
wherein the maximum delay time among the plurality of transmission antennas is set to the first value smaller than 1/Fc when using frequency diversity for transmitting the signals, and
wherein the maximum delay time among the plurality of transmission antennas is set to the second value larger than 1/Fc when using multiuser diversity for transmitting the signals.
9. The transmission control method according to claim 6 ,
wherein the maximum delay time among the plurality of transmission antennas is set to the first value smaller than 1/Fc when using frequency diversity for transmitting the signals.
10. The transmission control method according to claim 6 ,
wherein the maximum delay time among the plurality of transmission antennas is set to the second value larger than 1/Fc when using multiuser diversity for transmitting the signals.
11. A transmission apparatus in a transmission system wherein slots are assigned to chunks divided in a frequency domain and in a time domain, the transmission apparatus comprising:
a plurality of transmission antennas;
a delay imparting section imparting delays to signals being supplied to the plurality of transmission antennas; and
a controller controlling the delays in response to using either a frequency diversity for transmitting the signals or a multiuser diversity for transmitting the signals such that a maximum delay time among the plurality of transmission antennas is set selectively to either a first value smaller than 1/Fc or a second value larger than 1/Fc where Fc denotes a frequency band width of each chunk.
12. The transmission apparatus according to claim 11 ,
wherein a directivity control is performed in the multiuser diversity for transmitting the signals.
13. The transmission apparatus according to claim 11 ,
wherein the maximum delay time among the plurality of transmission antennas is set to the first value smaller than 1/Fc when using frequency diversity for transmitting the signals, and
wherein the maximum delay time among the plurality of transmission antennas is set to the second value larger than 1/Fc when using multiuser diversity for transmitting the signals.
14. The transmission apparatus according to claim 11 , wherein the maximum delay time among the plurality of transmission antennas is
set to the first value smaller than 1/Fc when using frequency diversity for transmitting the signals.
15. The transmission apparatus according to claim 11 , wherein the maximum delay time among the plurality of transmission antennas is set to the second value larger than 1/Fc when using multiuser diversity for transmitting the signals.
16. A transmission system wherein slots are assigned to chunks divided in a frequency domain and in a time domain, the transmission system comprising:
a plurality of transmission antennas;
a receiving section receiving a determination of whether to transmit signals using either frequency diversity or multiuser diversity based on a selection between using frequency diversity and multiuser diversity; and
a controller controlling delays supplied to the plurality of transmission antennas in response to the determination of using a frequency diversity for transmitting the signals or a multiuser diversity for transmitting the signals such that a maximum delay time among a plurality of transmission antennas is set selectively to either a first value smaller than 1/Fc or a second value larger than 1/Fc where Fc denotes a frequency bandwidth of each chunk.
17. The transmission system according to claim 16 , wherein a directivity control is performed in the multiuser diversity for transmitting the signals.
18. The transmission system according to claim 16 , wherein the maximum delay time among the plurality of transmission antennas is set to the first value smaller than 1/Fc when using frequency diversity for transmitting the signals, and
wherein the maximum delay time among the plurality of transmission antennas is set to the second value larger than 1/Fc when using multiuser diversity for transmitting the signals.
19. The transmission system according to claim 16 , wherein the maximum delay time among the plurality of transmission antennas is set to the first value smaller than 1/Fc when using frequency diversity for transmitting the signals.
20. The transmission system according to claim 16 , wherein the maximum delay time among the plurality of transmission antennas is set to the second value larger than 1/Fc when using multiuser diversity for transmitting the signals.