Diversity transmitter and diversity transmission method
View Patent ↗The present invention concerns a diversity transmitter and a corresponding diversity transmission method. A symbol matrix is input for being processed, the processing comprising supplying columns of the symbol matrix to a plurality of at least two branches, each branch being supplied to a respective one of spatial channels for transmission. Parallelization is performed so as to provide within each branch at least two parallel channels allocated to a respective user. The symbol matrix signals is subjected on at least one of the branches to an invertible linear transformation with at least one fixed complex weight, the complex weight being different for at least two parallel channels.
1. A diversity transmitter, comprising:
a transmit symbol input device for inputting a symbol matrix to be forwarded to a transmit processing device;
the transmit processing device comprising
a supplying device for supplying columns of the symbol matrix to a plurality of at least two branches, each branch being supplied to a respective one of spatial channels for transmission to a receiver;
a parallelization device for providing within each branch at least two parallel channels allocated to a respective user; and
a weighting device for subjecting the symbol matrix signals on at least one of the branches to an invertible linear transformation with at least one fixed complex weight, the complex weight being different for at least two parallel channels.
2. A diversity transmitter according to claim 1 , wherein:
the invertible linear transformation is a unitary transformation.
3. A diversity transmitter according to claim 2 , wherein:
the unitary transformation is represented by a unitary weight matrix in which at least two elements have different non-zero complex phase values.
4. A diversity transmitter according to claim 1 , wherein:
the parallelization device performs multicode transmission using multiple spreading codes.
5. A diversity transmitter according to claim 4 , wherein:
multicode transmission is performed using a Hadamard transformation by multiplying the symbols with a spreading code matrix.
6. A diversity transmitter according to claim 4 , wherein:
the spreading code matrix is antenna specific.
7. A diversity transmitter according to claim 4 , wherein:
the spreading codes are non-orthogonal spreading codes.
8. A diversity transmitter according to claim 4 , wherein:
the spreading codes are orthogonal spreading codes.
9. A diversity transmitter according to claim 1 , wherein:
the fixed complex weights applied by the weighting device are time-invariant phase shift amounts for the respective parallel channels.
10. A diversity transmitter according to claim 9 , wherein:
the phase shift amounts are independent of the channels in at least two corresponding parallel channels transmitted out of different antennas.
11. A diversity transmitter according to claim 9 , wherein:
the phase shift amounts are dependent on the channels.
12. A diversity transmitter according to claim 9 , wherein:
the weighting matrix is identical for each branch.
13. A diversity transmitter according to claim 9 , wherein:
the weighting matrix differs for each branch.
14. A diversity transmitter according to claim 9 , wherein:
the phase offsets in parallel channels differ by a fixed amount.
15. A diversity transmitter according to claim 9 , wherein:
the phase offsets in parallel channels differ by a maximum possible amount.
16. A diversity transmitter according to claim 9 , wherein:
the phase offsets in parallel channels cover a full complex circle of 360°.
17. A diversity transmitter according to claim 9 , wherein:
the phase offsets in parallel channels are taken from a Phase Shift Keying configuration.
18. A diversity transmitter according to claim 9 , wherein:
the used phase offsets are signaled to the receiver.
19. A diversity transmitter according to claim 9 , wherein:
the phase offsets are at least partially controlled by the receiver via a feedback channel.
20. A diversity transmitter according to claim 1 , comprising:
a pre-diversification device arranged downstream from the input device and upstream the transmit processing device;
the pre-diversification device subjects the inputted symbol sequence to a diversification, at least one diversified symbol sequence being supplied to the processing device.
21. A diversity transmitter according to claim 20 , wherein:
the pre-diversification device subjects the input symbol sequence to at least one of an orthogonal transmit diversity, orthogonal space-time transmit diversity processing, a non-orthogonal space-time transmit diversity processing, delay diversity processing, Space-Time Trellis-Code processing, or Space-Time Turbo-Code processing.
22. A diversity transmitter according to claim 21 , wherein:
the pre-diversification device subjects the input symbol to more than one of the processings, the processings being performed in concatenation.
23. A diversity transmitter according to claim 1 , wherein:
the input symbol sequence is a channel coded sequence.
24. A diversity transmitter according to claim 23 , wherein:
the channel coding is Turbo coding, convolutional coding, block coding, or Trellis coding.
25. A diversity transmitter according to claim 1 , wherein:
all columns of the symbol matrix contain identical symbols.
26. A diversity transmitter according to claim 1 , wherein:
the symbol matrix is an orthogonal space-time block code.
27. A diversity transmitter according to claim 1 , wherein:
the symbol matrix is a non-orthogonal space-time block code.
28. A diversity transmitter according to claim 1 , wherein:
at least one column of the symbol matrix is different from another column.
29. A diversity transmitter according to claim 1 , wherein:
the symbol matrix contains at least two space-time code matrices, each modulating different symbols.
30. A diversity transmitter according to claim 1 , wherein:
all columns of the symbol matrix have different symbols, each parallel channel transmits from respective spatial channel in parallel at least two symbols allocated to the spatial channel.
31. A diversity transmission method, comprising:
inputting a symbol matrix for being processed,
the processing comprising supplying columns of the symbol matrix to a plurality of at least two branches, each branch being supplied to a respective one of spatial channels for transmission;
performing parallelization so as to provide within each branch at least two parallel channels allocated to a respective user; and
subjecting the symbol matrix signals on at least one of the branches to an invertible linear transformation with at least one fixed complex weight, the complex weight being different for at least two parallel channels.
32. A method according to claim 31 , wherein:
the invertible linear transformation is a unitary transformation.
33. A method according to claim 32 , wherein:
the unitary transformation is represented by a unitary weight matrix in which at least two elements have different non-zero complex phase values.
34. A method according to claim 31 , wherein:
the parallelization performs multicode transmission using multiple spreading codes.
35. A method according to claim 34 , wherein:
multicode transmission is performed using a Hadamard transformation by multiplying the symbols with a spreading code matrix.
36. A method according to claim 34 , wherein:
the spreading code matrix is antenna specific.
37. A method according to claim 34 , wherein:
the spreading codes are non-orthogonal spreading codes.
38. A method according to claim 34 , wherein:
the spreading codes are orthogonal spreading codes.
39. A method according to claim 31 , wherein:
the fixed complex weights applied by a weighting device are time-invariant phase shift amounts for the respective parallel channels.
40. A method according to claim 39 , wherein:
the phase shift amounts are independent of the channels in at least two corresponding parallel channels transmitted out of different antennas.
41. A method according to claim 39 , wherein:
the phase shift amounts are dependent on the channels.
42. A method according to claim 39 , wherein:
the weighting matrix is identical for each branch.
43. A method according to claim 39 , wherein:
the weighting matrix differs for each branch.
44. A method according to claim 39 , wherein:
the phase offsets in parallel channels differ by a fixed amount.
45. A method according to claim 39 , wherein:
the phase offsets in parallel channels differ by a maximum possible amount.
46. A method according to claim 39 , wherein:
the phase offsets in parallel channels cover a full complex circle of 360°.
47. A method according to claim 39 , wherein:
the phase offsets in parallel channels are taken from a Phase Shift Keying configuration.
48. A method according to claim 39 , wherein:
the used phase offsets are signaled to the receiver.
49. A method according to claim 39 , wherein:
the phase offsets are at least partially controlled by the receiver via a feedback channel.
50. A method according to claim 31 , comprising:
a pre-diversification step pefformed after inputting and before processing;
the pre-diversification step subjects the inputted symbol sequence to a diversification, at least one diversified symbol sequence being subjected to the processing.
51. A method according to claim 50 , wherein:
the pre-diversification step subjects the input symbol sequence to at least one of an orthogonal transmit diversity, orthogonal space-time transmit diversity processing, a non-orthogonal space-time transmit diversity processing, delay diversity processing, Space-Time Trellis-Code processing, or Space-Time Turbo-Code processing.
52. A method according to claim 51 , wherein:
the pre-diversification step subjects the input symbol to more than one of the processings, the processings being performed in concatenation.
53. A method according to claim 31 , wherein:
the input symbol sequence is a channel coded sequence.
54. A method according to claim 53 , wherein:
the channel coding is Turbo coding, convolutional coding, block coding, or Trellis coding.
55. A method according to claim 31 , wherein:
all columns of the symbol matrix contain identical symbols.
56. A method according to claim 31 , wherein:
the symbol matrix is an orthogonal space-time block code.
57. A method according to claim 31 , wherein:
the symbol matrix is a non-orthogonal space-time block code.
58. A method according to claim 31 , wherein:
at least one column of the symbol matrix is different from another column.
59. A method according to claim 31 , wherein:
the symbol matrix contains at least two space-time code matrices, each modulating different symbols.
60. A method according to claim 31 , wherein:
all columns of the symbol matrix have different symbols, each parallel channel transmits from respective spatial channel in parallel at least two symbols allocated to the spatial channel.