System and method for data detection in wireless communication systems

• US 20030218973A1
• Filed: 03/31/2003
• Published: 11/27/2003
• Est. Priority Date: 05/24/2002
• Status: Active Grant

• Current Assignee: Vecima Networks Incorporated
• Original Assignee: Vecima Networks Incorporated
• Inventors: Zamiri-Jafarian, Hossein, Oprea, Alexandru M.
• Granted Patent: US 7,327,800 B2
• Time in Patent Office: Days
• US Class Current: 370/210
• CPC Class Codes: H04B 7/0434 using multiple eigenmodes
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0618 Space-time coding
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0228 with direct estimation from sounding signals
• CPC Class Codes: H04L 25/0248 Eigen-space methods
• CPC Class Codes: H04L 27/2626 Arrangements specific to the transmitter only
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04L 27/2662 Symbol synchronisation

Abstract

A system and method for data detection in a wireless communication system wherein the system comprises a receiver for receiving spatial-subspace data transmitted over a plurality of spatial-subspace channels of a sub-carrier which may comprise at least one of coded and uncoded spatial-subspace channels. The receiver comprises a receiver weighting unit for providing receive-weighed spatial-subspace data and a data estimation unit for performing an iterative processing method on the receive-weighted spatial-subspace data to estimate output data related to the input data symbol stream. The-iterative processing method comprises successively processing data on each of the plurality of spatial-subspace channels in the receive-weighted spatial-subspace data.

Claims

1. A communication system for transmitting an input data symbol stream over a plurality of spatial-subspace channels of a sub-carrier between a transmitter and a receiver, wherein said transmitter comprises:

a) an encoder unit for processing a plurality of input data symbol sub-streams for providing a plurality of uncoded/coded input data symbol sub-streams comprising at least one of;

     1) at least one uncoded input data symbol sub-stream for allocation on a corresponding at least one uncoded spatial-subspace channel of said plurality of spatial-subspace channels and

     2) at least two coded input data symbol sub-streams for allocation on a corresponding at least two coded spatial-subspace channels of said plurality of spatial-subspace channels, said plurality of input data symbol sub-streams being derived from said input data symbol stream;

b) a transmitter weighting unit connected to said encoder unit for weighting said plurality of uncoded/coded input data symbol sub-streams with a transmit weight matrix corresponding to said sub-carrier for distributing said plurality of uncoded/coded input data symbol sub-streams along said plurality of spatial-subspace channels and providing transmit-weighted spatial-subspace data;

wherein, said receiver comprises;

c) a receiver weighting unit for receiving spatial-subspace data related to said transmit-weighted spatial-subspace data and weighting said spatial-subspace data with a receive weight matrix for providing receive-weighted spatial-subspace data; and

,

d) a data estimation unit connected to said receiver weighting unit for receiving and performing an iterative processing method on said receive-weighted spatial-subspace data to estimate output data related to said input data symbol stream, said iterative processing method comprising successively processing data on each of said plurality of spatial-subspace channels in said receive-weighted spatial-subspace data.

2. The communication system of claim 1, wherein said plurality of spatial-subspace channels comprise only uncoded spatial-subspace channels and said data estimation unit is adapted to perform a successive interference cancellation method for providing said estimated output data by detecting receive-weighted data symbols on one of said uncoded spatial-subspace channels, subtracting detected receive-weighted data symbols from the receive-weighted spatial-subspace data and iteratively processing receive-weighted spatial-subspace data on remaining uncoded spatial-subspace channels in a similar fashion.

3. The communication system of claim 2, wherein the uncoded spatial-subspace channels are processed in order of decreasing signal to noise plus interference ratio.

4. The communication system of claim 1, wherein said plurality of spatial-subspace channels comprise only said at least two coded spatial-subspace channels and said data estimation unit is adapted to perform an iterative decoding/detection method on the receive-weighted spatial-subspace data for providing said estimated output data, with one iteration of said decoding/detection method comprising:

(1) decoding and detecting receive-weighted coded data symbols transmitted on at least a portion of said at least two coded spatial-subspace channels and replacing said receive-weighted coded data symbols in said receive-weighted spatial-subspace data with detected coded data symbols; and

, (2) processing receive-weighted spatial-subspace data on remaining coded spatial-subspace channels in a similar fashion.

5. The communication system of claim 4, wherein said at least two coded spatial-subspace channels comprise pairs of coded spatial-subspace channels which are processed in order of decreasing signal to noise plus interference ratio.

6. The communication system of claim 1, wherein said plurality of spatial-subspace channels comprise said at least two coded spatial-subspace channels and said at least one uncoded spatial-subspace channel and said data estimation unit is adapted to perform an iterative decoding/detection method on the receive-weighted spatial-subspace data for providing said estimated output data, with one iteration of said decoding/detection method comprising:

(1) decoding and detecting receive-weighted coded data symbols transmitted on at least a portion of said at least two coded spatial-subspace channels and replacing said receive-weighted coded data symbols in said receive-weighted spatial-subspace data with detected coded data symbols;

and, (2) estimating and detecting uncoded data symbols transmitted on said at least one uncoded spatial-subspace channel.

7. The communication system of claim 6, wherein said at least two coded spatial-subspace channels comprise pairs of coded spatial-subspace channels which are processed in step (1) in order of decreasing signal to noise plus interference ratio, and said at least one uncoded spatial-subspace channel is processed in step (2) in order of decreasing signal to noise plus interference ratio.

8. The communication system of claim 1, wherein said data estimation unit comprises a de-mapper unit that utilizes one of:

1) a hard-decision method on detected data for providing output data bits as said estimated output data, and

     2) a soft-decision method on detected data for providing output data symbols with associated confidence levels as said estimated output data.

9. The communication system of claim 1, wherein said transmitter further comprises a first data mapper unit for mapping an input data bit stream to said input data symbol stream according to a modulation scheme having a constellation, and a subspace allocation unit for converting said input data symbol stream into said plurality of input data symbol sub-streams for allocation over said plurality of spatial-subspace channels, said first data mapper being connected to said subspace allocation unit, wherein said subspace allocation unit and said first data mapper unit operate in unison for implementing a multi-resolution modulation scheme wherein input data symbols which are further apart from one another in said constellation are allocated to one of said plurality of input data symbol sub-streams associated with one of said plurality of spatial-subspace channels having a low signal-to-noise-plus-interference ratio with respect to said plurality of spatial-subspace channels.

10. The communication system of claim 9, wherein input data symbols which are closer to one another in said constellation are allocated to one of said plurality of input data symbol sub-streams associated with one of said plurality of spatial-subspace channels having a high signal-to-noise-plus-interference ratio with respect to said plurality of spatial-subspace channels.

11. A method for transmitting an input data symbol stream over a plurality of spatial-subspace channels of a sub-carrier between a transmitter and a receiver, wherein at the transmitter the method comprises:

a) processing a plurality of input data symbol sub-streams for providing a plurality of uncoded/coded input data symbol sub-streams comprising at least one of;

     1) at least one uncoded input data symbol sub-stream for allocation on a corresponding at least one uncoded spatial-subspace channel of said plurality of spatial-subspace channels and

     2) at least two coded input data symbol sub-streams for allocation on a corresponding at least two coded spatial-subspace channels of said plurality of spatial-subspace channels, said plurality of input data symbol sub-streams being derived from said input data symbol stream;

b) weighting said plurality of uncoded/coded input data symbol sub-streams with a transmit weight matrix corresponding to said sub-carrier for distributing said plurality of uncoded/coded input data symbol sub-streams along said plurality of spatial-subspace channels and providing transmit-weighted spatial-subspace data;

wherein, at the receiver the method further comprises;

c) receiving spatial-subspace data related to said transmit-weighted spatial-subspace data and weighting said spatial-subspace data with a receive weight matrix for providing receive-weighted spatial-subspace data; and

,

d) performing an iterative processing method on said receive-weighted spatial-subspace data to estimate output data related to said input data symbol stream, said iterative processing method comprising successively processing data on each of said plurality of spatial-subspace channels in said receive-weighted spatial-subspace data.

12. The method of claim 11, wherein said plurality of spatial-subspace channels comprise only uncoded spatial-subspace channels and step (d) comprises performing a successive interference cancellation method for providing said estimated output data by detecting receive-weighted data symbols on one of said uncoded spatial-subspace channels, subtracting detected receive-weighted data symbols from the receive-weighted spatial-subspace data and iteratively processing receive-weighted spatial-subspace data on remaining uncoded spatial-subspace channels in a similar fashion.

13. The method of claim 12, wherein step (d) further comprises processing the uncoded spatial-subspace channels in order of decreasing signal to noise plus interference ratio.

14. The method of claim 11, wherein said plurality of spatial-subspace channels comprise only said at least two coded spatial-subspace channels and step (d) comprises performing an iterative decoding/detection method on the receive-weighted spatial-subspace data for providing said estimated output data, with one iteration of said decoding/detection method comprising:

(1) decoding and detecting receive-weighted coded data symbols transmitted on at least a portion of said at least two spatial-subspace channels and replacing said receive-weighted coded data symbols in said receive-weighted spatial-subspace data with detected coded data symbols; and

, (2) processing receive-weighted spatial-subspace data on remaining coded spatial-subspace channels in a similar fashion.

15. The method of claim 14, wherein said at least two coded spatial-subspace channels comprise pairs of coded spatial-subspace channels and step (d) further comprises processing said pairs of coded spatial-subspace channels in order of decreasing signal to noise plus interference ratio.

16. The method of claim 11, wherein said plurality of spatial-subspace channels comprise said at least two coded spatial-subspace channels and said at least one uncoded spatial-subspace channel and step (d) comprises performing an iterative decoding/detection method on the receive-weighted spatial-subspace data for providing said estimated output data, with one iteration of said decoding/detection method comprising:

(1) decoding and detecting receive-weighted coded data symbols transmitted on at least a portion of said at least two coded spatial-subspace channels and replacing said receive-weighted coded data symbols in said receive-weighted spatial-subspace data with detected coded data symbols; and

, (2) estimating and detecting uncoded data symbols transmitted on said at least one uncoded spatial-subspace channel.

17. The method of claim 16, wherein said at least two coded spatial-subspace channels comprise pairs of coded spatial-subspace channels and step (d) further comprises processing said pairs of coded spatial-subspace channels in step (1) in order of decreasing signal to noise plus interference ratio, and processing said at least one uncoded spatial-subspace channel in step (2) in order of decreasing signal to noise plus interference ratio.

18. The method of claim 11, wherein step (d) further comprises applying one of:

1) a hard-decision method on detected data for providing output data bits as said estimated output data, and

     2) a soft-decision method on detected data for providing output data symbols with associated confidence levels as said estimated output data.

19. The method of claim 11, wherein said method further comprises mapping an input data bit stream to said input data symbol stream according to a modulation scheme having a constellation and converting said input data symbol stream into said plurality of input data symbol sub-streams for allocation over said plurality of spatial-subspace channels, wherein said converting and said mapping is done in unison for implementing a multi-resolution modulation scheme wherein input data symbols which are further apart from one another in said constellation are allocated to one of said plurality of input data symbol sub-streams associated with one of said plurality of spatial-subspace channels having a low signal-to-noise-plus-interference ratio with respect to said plurality of spatial-subspace channels.

20. The method of claim 19, wherein input data symbols which are closer to one another in said constellation are allocated to one of said plurality of input data symbol sub-streams associated with one of said plurality of spatial-subspace channels having a high signal-to-noise-plus-interference ratio with respect to said plurality of spatial-subspace channels.

21. A receiver for receiving spatial-subspace data transmitted over a plurality of spatial-subspace channels of a sub-carrier, said spatial-subspace data comprising a plurality of uncoded/coded data symbol sub-streams comprising at least one of:

1) at least one uncoded input data symbol sub-stream for allocation on a corresponding at least one uncoded spatial-subspace channel of said plurality of spatial-subspace channels and

     2) at least two coded input data symbol sub-streams for allocation on a corresponding at least two coded spatial-subspace channels of said plurality of spatial-subspace channels, wherein said receiver comprises;

a) a receiver weighting unit for weighting said spatial-subspace data with a receive weight matrix for providing receive-weighted spatial-subspace data; and

,

b) a data estimation unit connected to said receiver weighting unit for receiving and performing an iterative processing method on said receive-weighted spatial-subspace data to estimate output data related to said input data symbol stream, said iterative processing method comprising successively processing data on each of said plurality of spatial-subspace channels in said receive-weighted spatial-subspace data.

22. The receiver of claim 21, wherein said plurality of spatial-subspace channels comprise only uncoded spatial-subspace channels and said data estimation unit is adapted to perform a successive interference cancellation method for providing said estimated output data by detecting receive-weighted data symbols on one of said uncoded spatial-subspace channels, subtracting detected receive-weighted data symbols from the receive-weighted spatial-subspace data and iteratively processing receive-weighted spatial-subspace data on remaining uncoded spatial-subspace channels in a similar fashion.

23. The receiver of claim 21, wherein said plurality of spatial-subspace channels comprise only said at least two coded spatial-subspace channels and said data estimation unit is adapted to perform an iterative decoding/detection method on the receive-weighted spatial-subspace data for providing said estimated output data, with one iteration of said decoding/detection method comprising:

(1) decoding and detecting receive-weighted coded data symbols transmitted on at least a portion said at least two coded spatial-subspace channels and replacing said receive-weighted coded data symbols in said receive-weighted spatial-subspace data with detected coded data symbols; and

, (2) processing receive-weighted spatial-subspace data on remaining coded spatial-subspace channels in a similar fashion.

24. The receiver of claim 21, wherein said plurality of spatial-subspace channels comprise said at least two coded spatial-subspace channels and said at least one uncoded spatial-subspace channel and said data estimation unit is adapted to perform an iterative decoding/detection method on the receive-weighted spatial-subspace data for providing said estimated output data, with one iteration of said decoding/detection method comprising:

(1) decoding and detecting receive-weighted coded data symbols transmitted on at least a portion of said at least two coded spatial-subspace channels and replacing said receive-weighted coded data symbols in said receive-weighted spatial-subspace data with detected coded data symbols; and

, (2) estimating and detecting uncoded data symbols transmitted on said at least one uncoded spatial-subspace channel.

25. The receiver of claim 21, wherein said data estimation unit comprises a de-mapper unit that utilizes one of:

1) a hard-decision method on detected data for providing output data bits as said estimated output data, and

     2) a soft-decision method on detected data for providing output data symbols with associated confidence levels as said estimated output data.

26. A method for receiving spatial-subspace data transmitted over a plurality of spatial-subspace channels of a sub-carrier, said spatial-subspace data comprising a plurality of uncoded/coded data symbol sub-streams comprising at least one of:

1) at least one uncoded input data symbol sub-stream for allocation on a corresponding at least one uncoded spatial-subspace channel of said plurality of spatial-subspace channels and

     2) at least two coded input data symbol sub-streams for allocation on a corresponding at least two coded spatial-subspace channels of said plurality of spatial-subspace channels, wherein said method comprises;

a) weighting said spatial-subspace data with a receive weight matrix for providing receive-weighted spatial-subspace data; and

,

b) performing an iterative processing method on said receive-weighted spatial-subspace data to estimate output data related to said input data symbol stream, said iterative processing method comprising successively processing data on each of said plurality of spatial-subspace channels in said receive-weighted spatial-subspace data.

27. The method of claim 26, wherein said plurality of spatial-subspace channels comprise only uncoded spatial-subspace channels and step (b) comprises performing a successive interference cancellation method for providing said estimated output data by detecting receive-weighted data symbols on one of said uncoded spatial-subspace channels, subtracting detected receive-weighted data symbols from the receive-weighted spatial-subspace data and iteratively processing receive-weighted spatial-subspace data on remaining uncoded spatial-subspace channels in a similar fashion.

28. The method of claim 26, wherein said plurality of spatial-subspace channels comprise only said at least two coded spatial-subspace channels and step (b) comprises performing an iterative decoding/detection method on the receive-weighted spatial-subspace data for providing said estimated output data, with one iteration of said decoding/detection method comprising:

(1) decoding and detecting receive-weighted coded data symbols transmitted on at least a portion of said at least two spatial-subspace channels and replacing said receive-weighted coded data symbols in said receive-weighted spatial-subspace data with detected coded data symbols; and

, (2) processing receive-weighted spatial-subspace data on remaining coded spatial-subspace channels in a similar fashion.

29. The method of claim 26, wherein said plurality of spatial-subspace channels comprise said at least two coded spatial-subspace channels and said at least one uncoded spatial-subspace channel and step (b) comprises performing an iterative decoding/detection method on the receive-weighted spatial-subspace data for providing said estimated output data, with one iteration of said decoding/detection method comprising:

(1) decoding and detecting receive-weighted coded data symbols transmitted on at least a portion of said at least two coded spatial-subspace channels and replacing said receive-weighted coded data symbols in said receive-weighted spatial-subspace data with detected coded data symbols; and

, (2) estimating and detecting uncoded data symbols transmitted on said at least one uncoded spatial-subspace channel.

30. The method of claim 26, wherein step (d) further comprises applying one of:

1) a hard-decision method on detected data for providing output data bits as said estimated output data, and

     2) a soft-decision method on detected data for providing output data symbols with associated confidence levels as said estimated output data.

31. A communication system for transmitting input data over a plurality of spatial-subspace channels of a sub-carrier between a transmitter and a receiver, wherein said transmitter comprises:

a) an encoder unit for processing a plurality of input data symbol sub-streams for providing a plurality of uncoded/coded input data symbol sub-streams comprising at least one of;

     1) at least one uncoded input data symbol sub-stream for allocation on a corresponding at least one uncoded spatial-subspace channel of said plurality of spatial-subspace channels and

     2) at least two coded input data symbol sub-streams for allocation on a corresponding at least two coded spatial-subspace channels of said plurality of spatial-subspace channels, said transmitter transmitting data related to said plurality of uncoded/coded input data symbol sub-streams; and

,

wherein, said receiver comprises;

b) a data estimation unit for performing an iterative processing method on received spatial-subspace data to estimate output data related to said input data, said iterative processing method comprising successively processing data on each of said plurality of spatial-subspace channels in said received spatial-subspace data.

32. The communication system of claim 31, wherein said plurality of spatial-subspace channels comprise only uncoded spatial-subspace channels and said data estimation unit is adapted to perform a successive interference cancellation method for providing said estimated output data by detecting received data symbols on one of said uncoded spatial-subspace channels, subtracting detected received data symbols from the received spatial-subspace data and iteratively processing received spatial-subspace data on remaining uncoded spatial-subspace channels in a similar fashion.

33. The communication system of claim 31, wherein said plurality of spatial-subspace channels comprise only said at least two coded spatial-subspace channels and said data estimation unit is adapted to perform an iterative decoding/detection method on the received spatial-subspace data for providing said estimated output data, with one iteration of said decoding/detection method comprising:

(1) decoding and detecting received coded data symbols transmitted on at least a portion of said at least two coded spatial-subspace channels and replacing said received coded data symbols in said received spatial-subspace data with detected coded data symbols; and

, (2) processing received spatial-subspace data on remaining coded spatial-subspace channels in a similar fashion.

34. The communication system of claim 31, wherein said plurality of spatial-subspace channels comprise said at least two coded spatial-subspace channels and said at least one uncoded spatial-subspace channel and said data estimation unit is adapted to perform an iterative decoding/detection method on the received spatial-subspace data for providing said estimated output data, with one iteration of said decoding/detection method comprising:

(1) decoding and detecting received coded data symbols transmitted on at least a portion of said at least two coded spatial-subspace channels and replacing said received coded data symbols in said received spatial-subspace data with detected coded data symbols; and

, (2) estimating and detecting uncoded data symbols transmitted on said at least one uncoded spatial-subspace channel.

35. The communication system of claim 31, wherein said transmitter further comprises a first data mapper unit for mapping an input data bit stream to an input data symbol stream according to a modulation scheme having a constellation, and a subspace allocation unit for converting said input data symbol stream into said plurality of input data symbol sub-streams for allocation over said plurality of spatial-subspace channels, said first data mapper being connected to said subspace allocation unit, wherein said subspace allocation unit and said first data mapper unit operate in unison for implementing a multi-resolution modulation scheme wherein input data symbols which are further apart from one another in said constellation are allocated to one of said plurality of input data symbol sub-streams associated with one of said plurality of spatial-subspace channels having a low signal-to-noise-plus-interference ratio with respect to said plurality of spatial-subspace channels.

36. The communication system of claim 35, wherein input data symbols which are closer to one another in said constellation are allocated to one of said plurality of input data symbol sub-streams associated with one of said plurality of spatial-subspace channels having a high signal-to-noise-plus-interference ratio with respect to said plurality of spatial-subspace channels.

37. A method for transmitting input data over a plurality of spatial-subspace channels of a sub-carrier between a transmitter and a receiver, wherein at the transmitter the method comprises:

a) processing a plurality of input data symbol sub-streams for providing a plurality of uncoded/coded input data symbol sub-streams comprising at least one of;

     1) at least one uncoded input data symbol sub-stream for allocation on a corresponding at least one uncoded spatial-subspace channel of said plurality of spatial-subspace channels and

     2) at least two coded input data symbol sub-streams for allocation on a corresponding at least two coded spatial-subspace channels of said plurality of spatial-subspace channels, and transmitting data related to said plurality of uncoded/coded input data symbol sub-streams; and

,

wherein, at the receiver the method further comprises;

b) performing an iterative processing method on received spatial-subspace data to estimate output data related to said input data, said iterative processing method comprising successively processing data on each of said plurality of spatial-subspace channels in said received spatial-subspace data.

38. The method of claim 37, wherein said plurality of spatial-subspace channels comprise only uncoded spatial-subspace channels and step (b) comprises performing a successive interference cancellation method for providing said estimated output data by detecting received data symbols on one of said uncoded spatial-subspace channels, subtracting detected received data symbols from the received spatial-subspace data and iteratively processing received spatial-subspace data on remaining uncoded spatial-subspace channels in a similar fashion.

39. The method of claim 37, wherein said plurality of spatial-subspace channels comprise only said at least two coded spatial-subspace channels and step (b) comprises performing an iterative decoding/detection method on the received spatial-subspace data for providing said estimated output data, with one iteration of said decoding/detection method comprising:

(1) decoding and detecting received coded data symbols transmitted on at least a portion of said at least two spatial-subspace channels and replacing said received coded data symbols in said received spatial-subspace data with detected coded data symbols; and

, (2) processing received spatial-subspace data on remaining coded spatial-subspace channels in a similar fashion.

40. The method of claim 37, wherein said plurality of spatial-subspace channels comprise said at least two coded spatial-subspace channels and said at least one uncoded spatial-subspace channel and step (b) comprises performing an iterative decoding/detection method on the received spatial-subspace data for providing said estimated output data, with one iteration of said decoding/detection method comprising:

(1) decoding and detecting received coded data symbols transmitted on at least a portion of said at least two coded spatial-subspace channels and replacing said received coded data symbols in said received spatial-subspace data with detected coded data symbols; and

, (2) estimating and detecting uncoded data symbols transmitted on said at least one uncoded spatial-subspace channel.

41. The method of claim 37, wherein said method further comprises mapping an input data bit stream to an input data symbol stream according to a modulation scheme having a constellation and converting said input data symbol stream into said plurality of input data symbol sub-streams for allocation over said plurality of spatial-subspace channels, wherein said converting and said mapping is done in unison for implementing a multi-resolution modulation scheme wherein input data symbols which are further apart from one another in said constellation are allocated to one of said plurality of input data symbol sub-streams associated with one of said plurality of spatial-subspace channels having a low signal-to-noise-plus-interference ratio with respect to said plurality of spatial-subspace channels.

42. The method of claim 41, wherein input data symbols which are closer to one another in said constellation are allocated to one of said plurality of input data symbol sub-streams associated with one of said plurality of spatial-subspace channels having a high signal-to-noise-plus-interference ratio with respect to said plurality of spatial-subspace channels.