Apparatus using concatenations of signal-space codes for jointly encoding across multiple transmit antennas, and employing coordinate interleaving

• US 20060159195A1
• Filed: 01/19/2005
• Published: 07/20/2006
• Est. Priority Date: 01/19/2005
• Status: Active Grant

• Current Assignee: Nokia Corporation
• Original Assignee: Nokia Corporation
• Inventors: Ionescu, Dumitru Mihai, Reid, Tony
• Granted Patent: US 8,031,793 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H03M 13/25 Error detection or forward error correction by signal space coding, i.e. adding redundancy in the signal constellation, e.g. Trellis Coded Modulation [TCM] modulation codes H03M13/31
• CPC Class Codes: H03M 13/29 combining two or more codes or code structures, e.g. product codes, generalised product codes, concatenated codes, inner and outer codes
• CPC Class Codes: H03M 13/2972 Serial concatenation using convolutional component codes
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/005 Iterative decoding, including iteration between signal detection and decoding operation
• CPC Class Codes: H04L 1/006 Trellis-coded modulation
• CPC Class Codes: H04L 1/0065 Serial concatenated codes
• CPC Class Codes: H04L 1/0066 Parallel concatenated codes
• CPC Class Codes: H04L 1/0625 Transmitter arrangements
• CPC Class Codes: H04L 1/065 by means of convolutional encoding

Abstract

A system for transmitting data over a MIMO channel has a transmitter and a receiver. In the transmitter, the input data is encoded over at least two pipes by a concatenation of at least two constituent signal-space encoders. Each constituent encoder is used to generate, in response to the input data, a sequence of symbols from a channel alphabet having at least one dimension. Each symbol of the channel alphabet includes at least one complex symbol having real and imaginary coordinates. The transmitter interleaves the coordinates of the sequence of channel alphabet symbols, and transmits (from at least two transmit antennas) the interleaved coordinates. Preferably, each constituent encoder maximizes a minimum coordinate-wise Hamming distance between members of all valid pairs of symbol sequences, maximizes a minimum Euclidean distance between members of all valid pairs of different codewords, and obeys an equal eigenvalue criterion.

Claims

1. A method for transmitting data over multiple channels comprising:

encoding input data over at least two pipes by a concatenation of at least two constituent signal-space encoders, in which each constituent encoder is used to generate, in response to said input data, a sequence of symbols from a channel alphabet having at least one dimension, each symbol of said channel alphabet comprising at least one complex symbol having real and imaginary coordinates;

interleaving the coordinates of said sequence of channel alphabet symbols into codewords that comprise frames; and

,

transmitting the frames from at least two transmitting antennas.

2. A method according to claim 1, further comprising at least one of puncturing and repeating at least some of the sequence of symbols resulting from concatenation and interleaving.

3. A method according to claim 1, in which each constituent signal-space encoder operates

maximize a minimum coordinate-wise Hamming distance between members of all valid pairs of sequences of symbols;

maximize a minimum Euclidean distance between members of all valid pairs of different codewords; and

obey an equal eigenvalue criterion.

4. A method according to claim 1, in which said constituent signal-space encoders each comprise a trellis encoder.

5. A method according to claim 1, further comprising interleaving a bit stream input into each constituent signal-space encoder such that each constituent signal space encoder operates on a different stream of input bits.

6. A method according to claim 1, further comprising interleaving a bit stream input into each constituent signal-space encoder except one of said signal-space encoders, such that all constituent signal space encoders operate on a different stream of input information bits.

7. A method according to claim 1, further comprising, prior to encoding input data and for each constituent signal-space encoder:

parsing an input data stream into groups of k bits, where k is an integer; and

interleaving said groups of k bits,

whereby each encoder operates on a different sequence of groups of input bits.

8. A method according to claim 1, further comprising, prior to encoding input data and for each constituent signal-space encoder except one:

parsing an input data stream into groups of k bits; and

interleaving said groups of k bits,

whereby each encoder operates on a different sequence of groups of input bits.

9. A method for decoding data received over multiple channels, said data characterized by a concatenated and coordinate-interleaved structure, comprising:

demodulating received data;

passing the demodulated data through a first decoder to form an intermediate output;

deinterleaving coordinates of the intermediate output to generate a plurality of streams of extrinsic information pertaining to the deinterleaved coordinates;

inputting into each of a plurality of decoders at least one of said plurality of streams and a feedback stream from another of said plurality of decoders; and

permuting said feedback streams to derive compatible feedback signals.

10. The method according to claim 9 wherein permuting comprises, for at least one iteration, the compatible feedback signals derive from extrinsic probabilities corresponding to a concatenated outer code.

11. The method according to claim 9 wherein permuting comprises, for only a first iteration, the first decoder operates to replace joint probabilities for punctured elements with equal probabilities, said elements comprising real coordinates of complex symbols of the received data.

12. A transmitter comprising:

a joint encoder comprising at least two constituent signal-space encoders, said joint encoder for encoding input data over at least two pipes by concatenating outputs from the at least two constituent signal-space encoders, in which each said constituent encoder is used to generate, in response to said input data, a sequence of symbols from a channel alphabet having at least one dimension, each symbol of said channel alphabet comprising at least one complex symbol having real and imaginary coordinates;

a coordinate interleaver having an input coupled to an output of the joint encoder for interleaving the coordinates of said sequence of channel alphabet symbols; and

,

at least two transmit antennas each having an input coupled to an output of the coordinate interleaver for transmitting the interleaved coordinates from said sequence of channel alphabet symbols.

13. The transmitter of claim 12 further comprising:

means for at least one of puncturing and repeating at least some of the sequence of symbols, said means disposed between the coordinate interleaver and the antennas.

14. The transmitter of claim 12, wherein each constituent signal-space encoder is adapted to:

maximize a minimum coordinate-wise Hamming distance between members of all valid pairs of sequences of symbols;

maximize a minimum Euclidean distance between members of all valid pairs of different codewords that are to be output from the coordinate interleaver; and

obey an equal eigenvalue criterion.

15. The transmitter of claim 12, wherein said constituent signal-space encoders each comprise a trellis encoder.

16. The transmitter of claim 12, further comprising at least two bit interleavers, each disposed such that each signal-space encoder has an input coupled to an output of a bit interleaver.

17. The transmitter of claim 12, further comprising at least one bit interleaver, each disposed such that each signal-space encoder save one has an input coupled to an output of a bit interleaver.

18. The transmitter of claim 12, further comprising, for each constituent signal-space encoder:

means for parsing an input data stream into groups of k bits; and

an interleaver for interleaving said groups of k bits,

whereby each signal-space encoder receives as input a different sequence of bits.

19. The transmitter of claim 12, further comprising, for each constituent signal-space encoder save one:

means for parsing an input data stream into groups of k bits; and

an interleaver for interleaving said groups of k bits, whereby each signal-space encoder receives as input a different sequence of bits.

20. A receiver for decoding data received over multiple channels, said data characterized by a concatenated and coordinate-interleaved structure, comprising:

at least two antennas for receiving data over multiple channels;

a demodulator having an input coupled to an output of said antennas;

a serial decoder having as inputs an output of the demodulator and a serial feedback, said serial decoder for decoding an inner code;

at least two parallel decoders each having a first input coupled to an output of the serial decoder and a feedback input coupled to a feedback output of another parallel decoder, each parallel decoder operating to deinterleave coordinates of its respective first input and decode an outer code thereof, and each further comprising a second output; and

a calculating module having inputs coupled to each of the second outputs of the parallel decoders and an output coupled to the serial feedback of the serial decoder.

21. The receiver of claim 20, wherein the serial decoder decodes the inner code by deriving extrinsic information about interleaved coordinates input thereto.

22. The receiver of claim 20, wherein the receiver operates to permute decoding at the parallel decoders until compatible feedback signals are achieved that derive from extrinsic probabilities corresponding to a concatenated outer code.

23. The receiver of claim 20, wherein the calculating module provides an equal probabilities result on its output at least until it receives a signal on each of its inputs.

24. An apparatus for transmitting data over multiple channels comprising:

means for encoding and concatenating input data over at least two pipes by generating, from the input data, a sequence of channel alphabet symbols, each symbol comprising at least one complex symbol having real and imaginary coordinates;

means for interleaving the coordinates of said sequence of symbols into codewords that each comprise a transmission frame; and

, means for transmitting the frames from at least two transmitting antennas.

25. An apparatus for operating on data received over multiple channels, said data characterized by a concatenated and coordinate-interleaved structure, comprising:

means for receiving data over multiple channels;

means for demodulating the received data;

means for decoding an inner code of the demodulated received data using information about interleaved coordinates;

means for deinterleaving coordinates that are output from the means for decoding an inner code;

parallel means for decoding an outer code of the demodulated received data, each of said parallel means using a feedback from another of said parallel means for decoding an outer code; and

means for determining extrinsic probabilities of an outer code of the received data from outputs of each of the parallel means, said extrinsic probabilities provided as an output that is coupled to an input of the means for decoding an inner code.

26. A program of machine-readable instructions, tangibly embodied on an information bearing medium and executable by a digital data processor, to perform actions directed toward transmitting a stream of input data, the actions comprising:

encoding input data over at least two pipes by a concatenation of at least two constituent signal-space encoders, in which each constituent encoder is used to generate, in response to said input data, a sequence of symbols from a channel alphabet having at least one dimension, each symbol of said channel alphabet comprising at least one complex symbol having real and imaginary coordinates;

interleaving the coordinates of said sequence of channel alphabet symbols into codewords that comprise transmission frames; and

,

transmitting the frames from at least two transmit antennas.