0540232-A2 is referenced by 32 patents and cites 7 patents.

Digital signals (from 101), such as digitized television signals, are subjected to a source coding step (by 104) followed by a channel mapping step (by 114 and 115). The source coding step causes the signal to be represented by first and second data streams (on 105, 106). The first stream carries data regarded as more important and the second carries data regarded as less important. In the channel mapping step, the mapping is such that the data elements of the various data streams have differing probabilities of being erroneously detected at the receiver. The channel mapping step includes at least one multi-level coding step. The signal constellations used in the channel mapping step are partitioned into supersymbols, in which the distance between the symbols comprising at least ones of the supersymbols is less than a parameter referred to as the maximum intra-subset distance (MID).; Additionally, in some constellations, the minimum distance between at least ones of the symbols of at least one of the supersymbols is greater than die minimum distance between the symbols of the constellation as a whole while, again, still being less than the MID. The first data stream is used to identify a sequence of supersymbols, while the second data stream is used to select particular symbols from the identified supersymbols.

Title
Coded modulation with unequal error protection.
Application Number
EP19920309609 19921021
Publication Number
0540232 (A2)
Application Date
October 21, 1992
Publication Date
May 5, 1993
Inventor
Seshadri Nambirajan
US
Calderbank Arthur Robert
US
Assignee
American Telephone & Telegraph
US
IPC
H04L 27/34
H04N 07/26
H04N 07/24
H04L 27/34
H04B 14/04
H03M 13/00
H03M 07/14
H04N 07/26
H04N 07/24
H04L 27/34
H04B 14/04
H03M 13/35
H03M 13/00
H03M 07/14
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