Open-loop diversity technique for systems employing four transmitter antennas
First Claim
1. A method for use in a transmitter adapted to employ four transmit elements to transmit a source bit stream, the method comprising the steps of:
- dividing said source bit stream into L data substreams, L>
2; and
grouping derivatives of symbols derived from each of said data substreams to form four transmit time sequences, one sequence for each transmit element, each of said time sequences spanning L symbol periods, at least one of said derivatives of said symbols being a complex conjugate of one of said symbols.
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Abstract
When using four transmit antennas, conventional channel coding is employed for a decoupled space-time coding approach for each of a number, L, of data substreams derived from the overall source bit stream. The symbols of the data substreams, after any encoding, are processed and the resulting derivatives of the encoded data substreams, which includes at least the complex conjugate of one of the encoded symbols, are grouped to form four transmit time sequences each one spanning L symbol periods which form a transmission matrix B. Each row of the matrix corresponds to an antenna, and the elements of each row represent the samples of a temporal sequence that is emitted by the antenna in L symbol periods. When L=4 the matrix B can be arranged as follows:
where b1, b2, b3, and b4 are the encoded symbols from the data substreams and * indicates complex conjugate.
21 Citations
60 Claims
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1. A method for use in a transmitter adapted to employ four transmit elements to transmit a source bit stream, the method comprising the steps of:
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dividing said source bit stream into L data substreams, L>
2; and
grouping derivatives of symbols derived from each of said data substreams to form four transmit time sequences, one sequence for each transmit element, each of said time sequences spanning L symbol periods, at least one of said derivatives of said symbols being a complex conjugate of one of said symbols. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A transmitter adapted for use with four transmit elements to transmit a source bit stream, comprising:
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means for dividing said source bit stream into L data substreams, L>
2;
means grouping derivatives of symbols derived from each of said data substreams to form four transmit time sequences, each of said time sequences spanning L symbol periods, at least one of said derivatives of said symbols being a complex conjugate of one of said symbols; and
means for grouping said time sequences into a matrix, each time sequence being a row of said matrix. - View Dependent Claims (10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 24, 26, 27, 28, 29, 30)
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16. A transmitter for use with four transmit elements for transmitting a source bit stream, comprising:
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a demultiplexer that divides said source bit stream into L data substreams, L>
2;
a space time multiplexer that groups derivatives of symbols derived from of each of said data sub streams to form four transmit time sequences, each of said time sequences spanning L symbol periods, at least one of said derivatives of said symbols being a complex conjugate of one of said symbols, said time sequences groups being arranged as a matrix, in which each time sequence is a row of said matrix.
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25. A transmitter adapted for use with four transmit elements to transmit a source bit stream, comprising:
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a demultiplexer that divides said source bit stream into L data substreams, L>
2;
L encoders, each of said encoders receiving and encoding one of said data substreams to produce encoded symbols;
a space time multiplexer that groups derivatives of said encoded symbols derived from each of said data substreams to form four transmit time sequences, each of said time sequences spanning L symbol periods, at least one of said derivatives of said symbols being a complex conjugate of one of said symbols, said time sequences groups being arranged as a matrix, in which each time sequence is a row of said matrix.
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31. A method for use in processing received signals that were transmitted via four transmit elements of a transmitter, said transmitter being adapted to transmit a source bit stream by dividing said source bit stream into L data substreams, L>
- 2 and grouping derivatives of symbols derived from each of said data substreams to form four transmit time sequences, one sequence for each transmit element, each of said time sequences spanning L symbol periods, at least one of said derivatives of said symbols being a complex conjugate of one of said symbols, said method comprising the step of;
developing, from a received signal including versions of said time sequences which have been combined by the channel between said transmit elements and said receiver, reconstructed versions of said symbols derived from each of said data substreams. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
- 2 and grouping derivatives of symbols derived from each of said data substreams to form four transmit time sequences, one sequence for each transmit element, each of said time sequences spanning L symbol periods, at least one of said derivatives of said symbols being a complex conjugate of one of said symbols, said method comprising the step of;
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42. Apparatus for use in processing received signals that were transmitted via four transmit elements of a transmitter, said transmitter being adapted to transmit a source bit stream by dividing said source bit stream into L data substreams, L>
- 2 and grouping derivatives of symbols derived from each of said data substreams to form four transmit time sequences, one sequence for each transmit element, each of said time sequences spanning L symbol periods, at least one of said derivatives of said symbols being a complex conjugate of one of said symbols, said apparatus comprising;
a matrix multiplier for supplying as an output matched filtered signals which are versions of preprocessed signals derived from a received signal which includes versions of said time sequences which have been combined by the channel between said transmit elements and said receiver; and
a baseband signal processing unit receiving said matched filtered signals as an input and developing therefrom reconstructed versions of said symbols derived from each of said data substreams. - View Dependent Claims (43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60)
- 2 and grouping derivatives of symbols derived from each of said data substreams to form four transmit time sequences, one sequence for each transmit element, each of said time sequences spanning L symbol periods, at least one of said derivatives of said symbols being a complex conjugate of one of said symbols, said apparatus comprising;
Specification