Method for detecting erasures in received digital data

Method for detecting erasures in a stream of sets of digital signal values received at a receiver side after transmission from a transmission side, each set in said stream of sets representing one symbol, characterized in that a subset of each of said sets of digital signal values is modulated on a distinct carrier signal corresponding to one of a number of predetermined subset related points and to a receipt point on a carrier dependent modulation representing map respectively, and that said method includes the steps of;

• selecting for each said receipt point a nearest point of said predetermined subset related points;
• calculating a weighted distance between said receipt point and said nearest of said predetermined subset related points by multiplying the distance between said receipt and said nearest of said predetermined subset related points by a map dependent weight factor having a value that depends on the receipt point;
• summing, to obtain a result sum, the weighted distance calculated for each said receipt point for all subsets of a set;
• marking a set as an erasure when the result sum exceeds a predetermined threshold,
• wherein for each said error a transmit power and said carrier dependent modulation representing map are chosen such that a required signal quality characteristic for a said subset modulated on a respective carrier is met;
• and
• wherein said signal quality characteristic is an error probability of said digital signal values included in said subsets.

Method for detecting erasures in a stream of sets of digital signal values received at a receiver side after transmission from a transmission side, each set in said stream of sets representing one symbol, characterized in that a subset of each of said sets of digital signal values is modulated on a distinct carrier signal, each transmitted and received thus modulated carrier signal corresponding to one of a number of predetermined subset related points and to a receipt point on a carrier dependent modulation representing map respectively, and that said method includes the step of:

• selecting for each said receipt point nearest point of said predetermined subset related points;
• calculating weighted distance between said receipt point and said nearest of said predetermined subset related points by multiplying the distance between said receipt point and said nearest of said predetermined subset related points by a map dependent weight factor having a value that depends on the receipt point, wherein said distance is a Manhattan distance between said receipt point and said nearest of said predetermined subset related points;
• summing, to obtain a result sum, the weighted distance calculated for each said receipt point for all subsets of a set;
• and
• marking a set as an erasure when the result sum exceeds a predetermined threshold.