METHOD FOR TRANSMITTING A SIGNAL IN MULTI-ANTENNA COMMUNICATION SYSTEM

• US 20080267318A1
• Filed: 04/21/2008
• Published: 10/30/2008
• Est. Priority Date: 04/19/2007
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Ko, Hyun Soo, Ihm, Bin Chul, Chung, Jae Hoon, Lee, Wook Bong, Lee, Mook Il
• Granted Patent: US 9,577,735 B2
• Time in Patent Office: Days
• US Class Current: 375/299
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• CPC Class Codes: H04B 7/0689 using different transmission schemes, at least one of them being a diversity transmission scheme
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04B 7/12 Frequency diversity

Abstract

A multi-input multi-output (MIMO) system considers either reliability for each antenna or a time/frequency location, and transmits a signal at an unequal ratio for each antenna according to the consideration result. The method for use in the MIMO system including multiple antennas includes processing a signal according to an unequal ratio transmission scheme employing the multiple antennas at an unequal ratio, and transmitting the processed signal via the multiple antennas.

Claims

1. A method for transmitting a signal in a Multiple-Input Multiple-Output (MIMO) system including multiple antennas comprising:

processing a plurality of symbols with a space-time/frequency code combined with time/frequency switched transmit diversity; and

transmitting the processed symbols via the multiple antennas at an unequal ratio of a first ratio and a second ratio in a subframe,

wherein the first ratio is larger than the second ratio, the first ratio being associated with a first antenna set having a part of the multiple antennas, and the second ratio being associated with a second antenna set having another part of the multiple antennas.

2. The method according to claim 1, wherein:

the first ratio and the second ratio are determined by a repetition number of the space-time/frequency code in the subframe.

3. The method according to claim 2, wherein:

the repetition number of the space-time/frequency code is fixed or changeable according to a system situation.

4. The method according to claim 1, wherein:

the first antenna set is selected at the first ratio in the subframe and the second antenna set is selected at the second ratio in the subframe.

5. The method according to claim 1, wherein:

transmission (Tx) power is allocated to the first antenna set at the first ratio in the subframe and transmission (Tx) power is allocated to the second antenna set at the second ratio in the subframe.

6. The method according to claim 4 or 5, wherein:

the first antenna set has higher reliability than the second antenna set.

7. The method according to claim 4 or 5, wherein;

the first antenna set transmits more reference symbols than the second antenna set in the subframe.

8. The method according to claim 5, wherein:

transmission (Tx) power is allocated by using a power-scaling matrix having different power-scaling factors per the multiple antennas or the antenna set.

9. The method according to claim 1, wherein:

for OFDM symbols transmitting at least one reference symbol in the subframe, an antenna transmitting at least one reference symbol is allocated with smaller weight than other antenna among antennas included in each antenna set.

10. The method according to claim 7, wherein:

for OFDM symbols transmitting at least one reference symbol in the subframe, at least one data symbol among the plurality of symbols is punctured and transmission (Tx) power of reference symbol is increased by amount of transmission (Tx) power for the punctured data symbol.

11. The method according to claim 1, wherein:

the processed symbols of a specific region are transmitted via the multiple antennas at an unequal ratio, the specific region being included among one or more regions divided from the subframe.

12. The method according to claim 11, wherein:

the one or more regions are divided according to whether reference symbols are transmitted or not in each region.

13. The method according to claim 11, wherein:

the one or more regions are divided according to how many antennas are associated with reference symbols transmitted in each region.

14. A method for receiving a signal in a Multiple-Input Multiple-Output (MIMO) system including multiple antennas comprising:

receiving a plurality of symbols via the multiple antennas at an unequal ratio of a first ratio and a second ratio in a subframe,

processing the plurality of symbols with a space-time/frequency code combined with time/frequency switched transmit diversity; and

wherein the first ratio is larger than the second ratio, the first ratio being associated with a first antenna set having a part of the multiple antennas, and the second ratio being associated with a second antenna set having another part of the multiple antennas.

15. A method for transmitting a signal in a Multiple-Input Multiple-Output (MIMO) system including multiple antennas comprising:

allocating power weights to a plurality of symbols per antenna;

transmitting the weighted symbols via the multiple antennas in a subframe,

wherein an antenna transmitting at least one reference symbol is allocated with smaller weight than other antenna among the multiple antennas for time unit transmitting at least one reference symbol in the subframe.

16. A method for transmitting a signal in a Multiple-Input Multiple-Output (MIMO) system comprising:

dividing time-frequency resources contained in a transmission (Tx) unit of the MIMO system into one or more regions;

determining a signal transmission scheme for each division region; and

transmitting the signal transmission according to the determined scheme.

17. The method according to claim 16, wherein:

the division region is determined by the presence or absence of a reference symbol.

18. The method according to claim 16, the method further comprising:

determining the signal transmission scheme in consideration of characteristics of reference symbols contained in the division region.

19. The method according to claim 18, wherein:

if the division region includes the reference symbols, an unequal ratio transmission scheme is applied to the division region, and

if the division region includes none of the reference symbols, an equal ratio transmission scheme is applied to the division region.