Method and apparatus using coordinate interleaving to increase diversity in a MIMO system
First Claim
1. A method for transmitting, with increased diversity in fading channels, an input signal from a plurality of transmit antennas, the method comprising:
- jointly encoding, across at least two pipes, and modulating an input signal into a codeword, the codeword spanning a frame and defined as at least one complex symbol that describes all complex values to be transmitted during all channel uses covered by the frame, each complex symbol having a first and a second coordinate;
after encoding and modulating, interleaving the coordinates within a transmission frame that corresponds to a predesignated number of channel uses by said encoder; and
transmitting the frame of interleaved coordinates by L transmit antennas, wherein L is an integer greater than one.
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Abstract
A method to increase diversity in MIMO fading channels interleaves coordinates of complex symbol(s) in a transmission frame after encoding and modulating. Specifically, an input signal is encoded and modulated into a codeword, jointly across at least two pipes, said pipes having space, time, frequency, or other nature, wherein the codeword spans a frame and is defined as at least one complex symbol whose complex values are all those to be transmitted during all channel uses covered by the frame. Each of the complex symbols have a first and second coordinate. After modulating, which may be combined with encoding in a signal space encoder, the coordinates are interleaved. In modulation, the complex symbols (typically two dimensional) may arise as elements of a multidimensional (typically greater than two dimensions) signal constellation, in which case those multidimensional constellation coordinates are the ones that are interleaved in the frame. The frame carrying the interleaved coordinates is transmitted by the first and at least second antennas, possible opposed sub-frames of the overall frame being transmitted separately by opposed antennas. A coset selector is used in some embodiments to maximize a minimum Hamming distance, and/or a minimum Euclidean distance, between coordinates within a coset to control diversity and/or coding gain. In some embodiments, the operation of the encoder and modulator is such as to maximize a minimum coordinate-wise Hamming distance, and/or a minimum Euclidean distance, between allowable codewords, and/or to provide additional structure for the allowable codewords. A method, transmitter, system, and mobile station are described.
72 Citations
40 Claims
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1. A method for transmitting, with increased diversity in fading channels, an input signal from a plurality of transmit antennas, the method comprising:
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jointly encoding, across at least two pipes, and modulating an input signal into a codeword, the codeword spanning a frame and defined as at least one complex symbol that describes all complex values to be transmitted during all channel uses covered by the frame, each complex symbol having a first and a second coordinate; after encoding and modulating, interleaving the coordinates within a transmission frame that corresponds to a predesignated number of channel uses by said encoder; and transmitting the frame of interleaved coordinates by L transmit antennas, wherein L is an integer greater than one. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A transmitter comprising:
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an encoder for jointly encoding, across at least two pipes, an input signal into a set of at least one complex symbols that span a frame that corresponds to a predesignated number of channel uses, each complex symbol having a first and a second coordinate; a modulator for adapting the encoder to a channel alphabet; a coordinate interleaver, having an input coupled to an output of the encoder and the modulator, for interleaving the coordinates of the set of at least one complex symbol within the frame; L transmit antennas having inputs coupled to an output of the coordinate interleaver for transmitting the frame, wherein L is an integer greater than one. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A system for communicating over fading channels with high diversity comprising a transmitter and a receiver, wherein the transmitter comprises:
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an encoder for jointly encoding, across at least two pipes, an input signal into a set of at least one complex symbols that span a frame that corresponds to a predesignated number of channel uses, each complex symbol having a first and a second coordinate; a modulator for adapting the encoder to a channel alphabet; a coordinate interleaver, having an input coupled to an output of the encoder and the modulator, for interleaving the coordinates of the set of at least one complex symbol within the frame; L transmit antennas having inputs coupled to an output of the coordinate interleaver for transmitting the frame; and the receiver comprises; M receive antennas for receiving the frame over a multi-path channel; a coordinate de-interleaver having an input coupled to an output of the receive antenna for de-interleaving coordinates in the frame; a demodulator for demodulating the received frame; and a decoder for decoding the de-interleaved coordinates; a mechanism for performing one or more iterations between demodulator and decoder; wherein L is an integer greater than one and M is an integer at least equal to one. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33)
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34. A mobile station comprising:
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an encoder for jointly encoding, across at least two pipes, an input signal into a set of at least one complex symbols that span a frame that corresponds to a predesignated number of channel uses, each complex symbol having a first and a second coordinate; a modulator for adapting an output of the encoder to a channel alphabet; a coordinate interleaver, having an input coupled to an output of the encoder and the modulator, for interleaving the coordinates of the set of at least one complex symbol within the frame; and L transmit antennas having inputs coupled to an output of the coordinate interleaver for transmitting the frame; wherein L is an integer greater than one. - View Dependent Claims (35, 36, 37, 38, 39, 40)
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Specification