Multicast coding methods and systems

1. A method for coding multicast information signals, the method comprising:

determining indications of signal transformations imposed by communication links with a plurality of receivers that are grouped into subsets of receivers;

generating a coding design by employing dimension parameters that are related to achievable capacity rates of the subsets of receivers and are determined by constraining a sum of the dimension parameters to be less than or equal to a dimension of a union of subspaces of signal values that are receivable by the receivers;

generating output signals by applying the coding design to multicast information to compensate for the signal transformations; and

transmitting the output signals to the plurality of receivers,

wherein each dimension parameter is determined for a different subset of receivers,

wherein each subspace of signal values corresponds to a different subset of receivers and denotes signal values that are receivable by receivers in a corresponding subset, and

wherein the generating further comprises determining a reduced subspace for each of the subspaces such that the dimension of each reduced subspace is equal to the dimension parameter that corresponds to the subset to which the reduced subspace corresponds and such that a dimension of a union of the reduced subspaces is equal to the sum of the dimension parameters.

2. The method of claim 1 , wherein each subspace of signal values are receivable only by receivers in the subset corresponding to the subspace.

3. The method of claim 1 , wherein the generating further comprises computing a basis of each reduced subspace of signal values.

4. The method of claim 3 , wherein the reduced subspaces are complementary.

5. The method of claim 1 , wherein the generating further comprises determining the achievable capacity rate for each subset by employing inequality formulations relating the dimension parameters to the achievable capacity rates.

6. The method of claim 5 , wherein the generating further comprises determining a parameter matrix that is partitioned in accordance with the dimension parameters and with the achievable capacity rates.

7. The method of claim 6 , wherein the generating further comprises sizing partitions of columns of the parameter matrix in accordance with the dimension parameters, sizing partitions of rows of the parameter matrix in accordance with the achievable capacity rates and populating the parameter matrix in overlapping partitions of rows and columns corresponding to subsets having at least one common receiver.

8. A non-transitory computer readable storage medium comprising a computer readable program, wherein the computer readable program when executed on a computer causes the computer to:

determine indications of signal transformations imposed by communication links with a plurality of receivers that are grouped into subsets of receivers;

generate a coding design by employing dimension parameters that are related to achievable capacity rates of the subsets of receivers and are determined by constraining a sum of the dimension parameters to be less than or equal a dimension of a union of subspaces of signal values that are receivable by the receivers; and

apply the coding design to multicast information to generate output signals for transmission to the plurality of receivers,

wherein each subspace denotes signal values that are receivable by receivers in a different subset, and

wherein the computer readable program further causes the computer to determine a reduced subspace for each of the subspaces such that the dimension of each reduced subspace is equal to the dimension parameter that corresponds to a subset to which the reduced subspace corresponds and such that a dimension of a union of the reduced subspaces is equal to the sum of the dimension parameters.

9. A system for coding multicast information signals, the system comprising:

a controller configured to determine indications of signal transformations imposed by communication links with a plurality of receivers that are grouped into subsets of receivers and configured to generate a coding design by employing dimension parameters that are related to achievable capacity rates of the subsets of receivers and are determined by constraining a sum of the dimension parameters to be less than or equal to a dimension of a union of subspaces of signal values that are receivable by the receivers;

a coder configured to generate output signals by applying the coding design to multicast information to compensate for the signal transformations; and

a transmitter configured to transmit the output signals to the plurality of receivers,

wherein each dimension parameter is determined for a different subset of receivers,

wherein each subspace of signal values corresponds to a different subset of receivers and denotes signal values that are receivable by receivers in a corresponding subset, and

wherein the coder is further configured to generate the coding design by determining a reduced subspace for each of the subspaces such that the dimension of each reduced subspace is equal to the dimension parameter that corresponds to the subset to which the reduced subspace corresponds and such that a dimension of a union of the reduced subspaces is equal to the sum of the dimension parameters.

10. The system of claim 9 , wherein each subspace of signal values are receivable only by receivers in the subset corresponding to the subspace.

11. The system of claim 9 , wherein the coder is further configured to generate the coding design by computing a basis of each reduced subspace of signal values.

12. The system of claim 11 , wherein the reduced subspaces are complementary.

13. The system of claim 9 , wherein the coder is further configured to generate the coding design by determining the achievable capacity rate for each subset by employing inequality formulations relating the dimension parameters with the achievable capacity rates.

14. The system of claim 13 , wherein the generating further comprises determining a parameter matrix that is partitioned in accordance to the dimension parameters and with the achievable capacity rates.

15. The system of claim 14 , wherein the coder is further configured to generate the coding design by sizing partitions of columns of the parameter matrix in accordance with the dimension parameters, sizing partitions of rows of the parameter matrix in accordance with the achievable capacity rates and populating the parameter matrix in overlapping partitions of rows and columns corresponding to subsets having at least one common receiver.