System for transmitting and receiving multi-input multi-output and method for transmitting and receiving multi-input multi-output using the same

1. A method for transmitting and receiving multi-input multi-output in a wireless backhaul network using a transmitter having a plurality of pairs of dual-polarized transmitting antennas and a receiver having a plurality of pairs of dual-polarized receiving antennas, comprising:

selecting and activating one pair of the plurality of pairs of dual-polarized transmitting antennas of the transmitter using a bit signal that is of a length of log 2 N T bits N T being the number of pairs of the plurality of pairs of dual-polarized transmitting antennas;

transmitting a signal through the selected pair of dual-polarized transmitting antennas, the signal including the bit signal and a data signal that is of a length of 2 log 2 Ω bits, Ω being the number of bits of a constellation corresponding to a modulation scheme of the data signal; and

selecting one of the plurality of pairs of dual-polarized receiving antennas of the receiver corresponding to the selected pair of dual-polarized transmitting antennas, and receiving the signal transmitted from the transmitter using the selected pair of dual-polarized receiving antennas.

2. The method of claim 1 , wherein the transmitting a signal includes transmitting a quadrature amplitude modulation (QAM) symbol.

3. The method of claim 1 , wherein the receiving the signal includes detecting a signal by applying a maximum likelihood (ML) signal detection technique to the received signal.

4. The method of claim 3 , wherein the selecting the pair of dual-polarized receiving antennas includes

when an angle between the selected pair of dual-polarized transmitting antennas of the transmitter is set to minimize an error probability of the receiver, selecting a pair of dual-polarized receiving antennas having an angle relatively similar to the angle between the selected pair of dual-polarized transmitting antennas.

5. A method for transmitting and receiving multi-input multi-output in a wireless backhaul network using a transmitter having a plurality of pairs of dual-polarized transmitting antennas and a receiver having a plurality of pairs of dual-polarized receiving antennas, comprising:

transmitting, by one pair of the plurality of pairs of dual-polarized transmitting antennas, a virtual data stream, the virtual data stream including a bit signal that is of a length of log 2 N T bits and a data signal that is of a length of 2 log 2 Ω bits, N T being the number of pairs of the plurality of pairs of dual-polarized transmitting antennas, Ω being the number of bits of a constellation corresponding to a modulation scheme of the data signal; and

receiving, by one pair of the plurality of pairs of dual-polarized receiving antennas selected corresponding to the one pair of dual-polarized transmitting antennas, the transmitted virtual data stream.

6. The method of claim 5 , wherein in the transmitting, the virtual data stream is transmitted using 4-QAM (quadrature amplitude modulation) constellation or 16-QAM constellation.

7. The method of claim 6 , wherein the transmitter is disposed by controlling an angle between the pair of the plurality of dual-polarized transmitting antennas of the transmitter so as to minimize an error probability of the receiver.

8. The method of claim 7 , wherein the error probability is associated with the angle between the pair of the plurality of dual-polarized transmitting antennas or the constellation.

9. A system for transmitting and receiving multi-input multi-output, comprising:

a transmitter including a plurality of pairs of dual-polarized transmitting antennas, the transmitter being configured to

select and activate one of the plurality of pairs of dual-polarized transmitting antennas using a bit signal that is of a length of log 2 N T bits N T being the number of pairs of the plurality of pairs of dual-polarized transmitting antennas, and

transmitting a signal through the selected pair of dual-polarized transmitting antennas, the signal including the bit signal and a data signal that is of a length of 2 log 2Ω bits, Ω being the number of bits of a constellation corresponding to a modulation scheme of the data signal; and

a receiver including a plurality of pairs of dual-polarized receiving antennas, the receiver being configured to receive the transmitted signal through one pair of the plurality of pairs of dual-polarized receiving antennas corresponding to the selected pair of dual-polarized transmitting antennas.

10. The system of claim 9 , wherein each pair of dual-polarized transmitting antennas includes a vertical polarization antenna and a horizontal polarization antenna.

11. The system of claim 10 , wherein the transmitter is so disposed that the plurality of pairs of dual-polarized transmitting antennas are inclined in a predetermined angle with respect to a reference dual-polarized transmitting antenna.

12. The system of claim 9 , wherein the transmitter transmits a quadrature amplitude modulation (QAM) symbol.

13. The system of claim 12 , wherein the transmitter is so disposed that angles between the dual-polarized transmitting antennas of the transmitter are the same, when using the 4-QAM constellation.

14. The system of claim 9 , wherein the transmitter is so disposed that an angle between the selected pair of dual-polarized transmitting antennas becomes an angle to minimize an error probability of the receiver, when using 16-QAM constellation.

15. The system of claim 9 , wherein

the transmitter includes a toll center which is connected to a core network, and

the receiver includes at least one remote node which wirelessly communicates with the toll center using a carrier frequency of 10 GHZ or more.