Method and a device for transmission with time-frequency mapping of symbols in sub-channels

1. A method of mapping data symbols at the input of a multi-carrier modulator, which data symbols are interleaved in blocks of K data symbols, into sub-channels, each of size equal to N SDC consecutive carriers scattered to one or more multi-carrier symbols, N SDC being a sub-multiple of the number of data symbols per block K, wherein the size N SDC of the sub-channels is determined as a function of a data symbol interleaving pattern diversity evaluated by a geometrical diversity criterion that includes quantifying interleaving dispersion within a sub-channel and between sub-channels.

2. The method of mapping at the input of a multi-carrier modulator according to claim 1 , wherein the data symbol interleaving pattern diversity between sub-channels is evaluated for groups of sub-channels that are spaced apart by no more than one sub-channel.

3. The method of mapping at the input of a multi-carrier modulator according to claim 2 , wherein the groups are made up of pairs of adjacent sub-channels.

4. The method of mapping at the input of a multi-carrier modulator according to claim 1 , comprising:

a first step of calculating a dispersion function ΔL(s) representing the minimum distance between the data symbols as a function of the difference s between interleaved data symbols for a given interleaving relationship L(k);

second step of pre-selecting different values of s, sub-multiples of K, for which the dispersion values satisfy an amplitude criterion; and

a third step of evaluating the geometrical diversity criterion for the different pre-selected values, the size N SDC of the sub-channels being determined to be equal to one of the pre-selected values for which the geometrical diversity criterion is at a maximum.

5. The method of mapping at the input of a multi-carrier modulator according to claim 1 , wherein K is equal to the size of a multi-carrier symbol.

6. The method of mapping at the input of a multi-carrier modulator according to claim 1 , wherein K is a multiple of the size of a multi-carrier symbol.

7. A processor configured to map data symbols at the input of a multi-carrier modulator, which data symbols are interleaved in blocks of K data symbols, into sub-channels each of size equal to N SDC consecutive carriers scattered over one or more multi-carrier symbols, where N SDC is a sub-multiple of K, it is also adapted to determine a sub-channel size as a function of a data symbol interleaving pattern diversity evaluated utilizing a geometrical diversity criterion that includes quantifying interleaving dispersion within a sub-channel and between sub-channels.

8. A transmitter of a multi-carrier signal, the transmitter comprising, between a modulator generating data symbols and a multi-carrier modulator generating multi-carrier symbols, an interleaver for interleaving a block of K data symbols, the transmitter being adapted in that it includes the processor according to claim 7 .

9. A system for transmitting a multi-carrier signal, the system comprising a transmitter and a receiver, and being adapted in that the transmitter is according to claim 8 .

10. An information medium comprising program instructions adapted to implement the method of mapping data symbols at the input of a multi-carrier modulator, which data symbols are interleaved in blocks of K data symbols, according to claim 1 , when said program is loaded and executed in a multi-carrier signal transmitter device.

11. A non-transitory computer program product that is directly loadable into the internal memory of a multi-carrier signal transmitter device, the product comprising software code portions for executing steps of the method of mapping data symbols at the input of a multi-carrier modulator, which data symbols are interleaved in blocks of K data symbols, according to claim 1 , when the program is executed by a multi-carrier signal transmitter device.

12. A method of mapping data symbols at the input of a multi-carrier modulator, which data symbols are interleaved in blocks of K data symbols, into sub-channels each of size equal to N SDC consecutive carriers scattered to one or more multi-carrier symbols, N SDC being a sub-multiple of the number of data symbols per block K, wherein the size N SDC of the sub-channels is determined as a function of a data symbol interleaving pattern diversity evaluated utilizing a geometrical diversity criterion that includes quantifying interleaving dispersion within a sub-channel and between sub-channels, the method comprising:

a first step of calculating a dispersion function ΔL(s) representing the minimum distance between the data symbols as a function of the difference s between interleaved data symbols for a given interleaving relationship L(k);

second step of pre-selecting different values of s, sub-multiples of K, for which the dispersion values satisfy an amplitude criterion; and

a third step of evaluating the geometrical diversity criterion for the different pre-selected values, the size N SDC of the sub-channels being determined to be equal to one of the pre-selected values for which the geometrical diversity criterion is at a maximum.

13. The method of mapping at the input of a multi-carrier modulator according to claim 12 , wherein the data symbol interleaving pattern diversity between sub-channels is evaluated for groups of sub-channels that are spaced apart by no more than one sub-channel.

14. The method of mapping at the input of a multi-carrier modulator according to claim 13 , wherein the groups are made up of pairs of adjacent sub-channels.

15. The method of mapping at the input of a multi-carrier modulator according to claim 12 , wherein K is equal to the size of a multi-carrier symbol.

16. The method of mapping at the input of a multi-carrier modulator according to claim 12 , wherein K is a multiple of the size of a multi-carrier symbol.

17. A processor configured to map data symbols at the input of a multi-carrier modulator, which data symbols are interleaved in blocks of K data symbols, into sub-channels each of size equal to N SDC consecutive carriers scattered over one or more multi-carrier symbols, where N SDC is a sub-multiple of K, it is also adapted to determine a sub-channel size as a function of a data symbol interleaving pattern diversity evaluated utilizing a geometrical diversity criterion that includes quantifying interleaving dispersion within a sub-channel and between sub-channels,

by calculating a dispersion function ΔL(s) representing the minimum distance between the data symbols as a function of the difference s between interleaved symbols for a given interleaving relationship L(k);

by pre-selecting different values of s, sub-multiples of K, for which the dispersion values satisfy an amplitude criterion; and

by evaluating the geometrical diversity criterion for the different pre-selected values, the size N SDC of the sub-channels being determined to be equal to one of the pre-selected values for which the geometrical diversity criterion is at a maximum.