Apparatus and method for space-frequency block coding/decoding in a communication system

A receiver in a communication system, the communication system having a transmitter that uses a plurality of(Nt) transmit antennas, the receiver comprising:

• at least one demodulator for demodulating a signal received through at least one receive antenna;
• a matrix generator for generating a channel response matrix by multiplying a channel coefficient matrix (H) by a predetermined pre-coding matrix (Θ), wherein the pre-coding matrix is produced by puncturing predetermined
• N
• t
• 2
• columns in an NtxNt Vandermonde matrix, sequentially grouping the rows of the punctured Vandermonde matrix by twos, and shifting one row of each group;
• and
• a signal combiner for calculating a Hermitian matrix of the channel response matrix, calculating a vector of size Nt by multiplying the Hermitian matrix by the demodulated signal, and dividing the vector into two vectors;
• wherein if a number of the transmit antennas is an even number (Nt=even number), the pre-coding matrix is
• Θ
• =
• 1
• N
• t
• /
• 2
• ⁡
• [
• 1
• α
• 0
• 1
• ⋯
• α
• 0
• N
• t
• /
• 2
• -
• 1
• 0
• 0
• ⋯
• 0
• 0
• 0
• ⋯
• 0
• 1
• α
• 0
• 1
• ⋯
• α
• 0
• N
• t
• /
• 2
• -
• 1
• ⋮
• ⋮
• ⋰
• ⋯
• ⋯
• ⋰
• ⋮
• ⋮
• 1
• α
• N
• t
• -
• 2
• 1
• ⋯
• α
• N
• t
• -
• 2
• N
• t
• /
• 2
• -
• 1
• 0
• 0
• ⋯
• 0
• 0
• 0
• ⋯
• 0
• 1
• α
• N
• t
• -
• 2
• 1
• ⋯
• α
• N
• t
• -
• 2
• N
• t
• /
• 2
• -
• 1
• ]
• where ai=exp(j2π(i+¼)/Nt), i=0, 1, 2, . . . , Nt/2−1.

A transmission method in a communication system using a plurality of (Nt) transmit antennas, comprising the steps of:

• pre-coding an input complex symbol sequence using a pre-coding matrix, the pre-coding matrix being produced by puncturing a unitary matrix in a predetermined method;
• generating a plurality of vectors by the symbols of the pre-coded symbol sequence by twos;
• space-frequency encoding each of the vectors by encoding each of the vectors in an Alamouti coding scheme;
• and
• providing each of the space-frequency encoded symbols to a predetermined Orthogonal Frequency Division Multiplexing (OFDM) modulator;
• wherein if a number the of transmit antennas is an even number (Nt=even number), the pre-coding matrix is
• Θ
• =
• 1
• N
• t
• /
• 2
• ⁡
• [
• 1
• α
• 0
• 1
• ⋯
• α
• 0
• N
• t
• /
• 2
• -
• 1
• 0
• 0
• ⋯
• 0
• 0
• 0
• ⋯
• 0
• 1
• α
• 0
• 1
• ⋯
• α
• 0
• N
• t
• /
• 2
• -
• 1
• ⋮
• ⋮
• ⋰
• ⋯
• ⋯
• ⋰
• ⋮
• ⋮
• 1
• α
• N
• t
• -
• 2
• 1
• ⋯
• α
• N
• t
• -
• 2
• N
• t
• /
• 2
• -
• 1
• 0
• 0
• ⋯
• 0
• 0
• 0
• ⋯
• 0
• 1
• α
• N
• t
• -
• 2
• 1
• ⋯
• α
• N
• t
• -
• 2
• N
• t
• /
• 2
• -
• 1
• ]
• where αi=exp(j2π(i+¼)/Nt), i=0, 1, 2, . . . , Nt/2−1, and
• wherein the pre-coding matrix is produced by puncturing predetermined
• N
• t
• 2
• columns in an NtxNt Vandermonde matrix, sequentially grouping the rows of the punctured matrix by twos, and shifting one row of each group.

A reception method in a communication system, the communication system having a transmitter that uses a plurality of (Nt) transmit antennas, the reception method comprising the steps of:

• demodulating a signal received through at least one receive antenna;
• generating a channel response matrix by multiplying a channel coefficient matrix (H) by a predetermined pre-coding matrix (Θ), wherein the pre-coding matrix is produced by puncturing predetermined
• N
• t
• 2
• columns in an Nt×Nt Vandermonde matrix, sequentially grouping the rows of the punctured Vandermonde matrix by twos, and shifting one row of each group;
• calculating a Hermitian matrix of the channel response matrix, calculating a vector of size Nt by multiplying the Hermitian matrix by the demodulated signal, and dividing the vector into two vectors;
• and
• estimating symbols transmitted from the transmitter by decoding each of the two vectors in a predetermined decoding method;
• wherein if a number of the transmit antennas is an even number (Nt=even number), the pre-coding matrix is
• Θ
• =
• 1
• N
• t
• /
• 2
• ⁡
• [
• 1
• α
• 0
• 1
• …
• α
• 0
• N
• t
• /
• 2
• -
• 1
• 0
• 0
• …
• 0
• 0
• 0
• …
• 0
• 1
• α
• 0
• 1
• …
• α
• 0
• N
• t
• /
• 2
• -
• 1
• ⋮
• ⋮
• ⋰
• …
• …
• ⋰
• ⋮
• ⋮
• 1
• α
• N
• t
• -
• 2
• 1
• …
• α
• N
• t
• -
• 2
• N
• t
• /
• 2
• -
• 1
• 0
• 0
• …
• 0
• 0
• 0
• …
• 0
• 1
• α
• N
• t
• -
• 2
• 1
• …
• α
• N
• t
• -
• 2
• N
• t
• /
• 2
• -
• 1
• ]
• where ai=exp(j2π(i+¼)/Nt), i=0, 1, 2, . . . , Nt/2−1.