METHOD OF TRANSMITTING DATA USING SPATIAL MULTIPLEXING

• US 20110134902A1
• Filed: 08/11/2009
• Published: 06/09/2011
• Est. Priority Date: 08/11/2008
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Ko, Hyun Soo, Ihm, Bin Chul, Lee, Moon Il, Kwon, Yeong Hyeon, Chung, Jae Hoon
• Granted Patent: US 8,711,828 B2
• Time in Patent Office: Days
• US Class Current: 370/344
• CPC Class Codes: H04B 7/02 Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas RAKE receivers H04B1/7115
• CPC Class Codes: H04B 7/0434 using multiple eigenmodes
• CPC Class Codes: H04B 7/068 using space frequency diversity space-frequency coding H04L1/0606
• CPC Class Codes: H04B 7/0682 using phase diversity (e.g. phase sweeping)
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04B 7/0697 using spatial multiplexing
• CPC Class Codes: H04J 2211/006 Single carrier frequency division multiple access [SC FDMA]
• CPC Class Codes: H04L 27/2617 using block codes
• CPC Class Codes: H04L 27/2636 with FFT or DFT modulators, e.g. standard single-carrier frequency-division multiple access [SC-FDMA] transmitter or DFT spread orthogonal frequency division multiplexing [DFT-SOFDM]
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0042 intra-user or intra-terminal allocation

Abstract

A data transmission method using spatial multiplexing is disclosed. The data transmission method using spatial multiplexing includes modulating at least one codeword to generate at least one modulation symbol, mapping the at least one modulation symbol to a layer whose number is determined according to its rank to generate a layer-mapped symbol stream, performing discrete Fourier transform (DFT) on the layer-mapped symbol stream to generate a frequency domain symbol stream, performing precoding on the frequency domain symbol stream, mapping the precoded frequency domain symbol stream to subcarriers, and then performing inverse fast Fourier transform (IFFT) on the precoded frequency domain symbol stream-mapped subcarriers to generate SC-FDMA symbols; and transmitting the SC-FDMA symbols by using a plurality of transmission antennas. Spatial multiplexing having a low PAPR can be possibly performed in an SC-FDMA system.

Claims

1. A method for transmitting data using spatial multiplexing, the method comprising:

modulating at least one codeword to generate at least one modulation symbol;

mapping the at least one modulation symbol to a layer whose number is determined according to its rank, to generate a layer-mapped symbol stream;

performing discrete Fourier transform (DFT) on the layer-mapped symbol stream to generate a frequency domain symbol stream;

performing precoding on the frequency domain symbol stream;

mapping the precoded frequency domain symbol stream to subcarriers, and then performing inverse fast Fourier transform (IFFT) on the precoded frequency domain symbol stream-mapped subcarriers to generate SC-FDMA symbols; and

transmitting the SC-FDMA symbols by using a plurality of transmission antennas,

wherein the performing of precoding comprises;

separately mapping the plurality of transmission antennas to each virtual antenna or mapping the plurality of transmission antennas to a single virtual antenna; and

performing permutation so that the at least one codeword can be distributedly transmitted through all of the plurality of transmission antennas.

2. The method of claim 1, wherein when the number of the plurality of transmission antennas and the size of the rank are equal, the plurality of transmission antennas are mapped to the virtual antennas in a one-to-one manner.

3. The method of claim 1, wherein if the size of the rank is larger than the number of plurality of transmission antennas, a signal of at least of one transmission antenna is phase shifted.

4. The method of claim 3, wherein the at least one transmission antenna and a transmission antenna that transmits the phase-shifted signal are mapped to the same virtual antenna.

5. The method of claim 3, wherein the single transmission antenna is mapped to a single virtual antenna.

6. The method of claim 1, wherein the subcarrier has a one-to-many mapping relation with the plurality of transmission antennas.

7. The method of claim 6, wherein the one-to-many mapping relation is one of H1 to H6 in Table shown below, wherein (x,y) represents that xth transmission antenna and yth transmission antenna are mapped to the same subcarrier:

8. The method of claim 1, wherein the permutation is changed in unit of each SC-FDMA symbol.

9. The method of claim 1, wherein the permutation is changed in units of a plurality of SC-FDMA symbols.

10. A data transmission method in a multi-antenna system, the method comprising:

transmitting a first precoded signal by using a first precoding matrix that combines a plurality of transmission antennas to a plurality of antenna groups to perform spatial multiplexing; and

transmitting a second precoded signal by using a second precoding matrix different from the first precoding matrix,

wherein the second precoding matrix is a precoding matrix that combines the plurality of transmission antennas to the plurality of antenna groups in the same manner as the first precoding matrix but includes different elements, or may be a precoding matrix that combines the plurality of transmission antennas to the plurality of antenna groups in a different manner from that of the first precoding matrix.

11. The method of claim 10, wherein the first and second precoding matrixes are applied in units of slots including a plurality of SC-FDMA symbols or a plurality of OFDM symbols.

12. The method of claim 10, wherein the first and second precoding matrixes are applied in units of SC-FDMA symbols or OFDM symbols.