Patent ID: 7894401

Claim:
A method of determining feedback in a communication system, the method comprising: mapping by a transmitting apparatus groups of bits of transmission data comprising data entities of different levels of importance to multi-level modulation symbols, wherein the bits of a respective data entity within each group of bits is mapped to a respective hierarchical part of the respective multi-level modulation symbol, transmitting the multi-level modulation symbols from the transmitting apparatus to a receiving apparatus, determining at the receiving apparatus for which data entities of the received data feedback should be provided, wherein said determining is based on (i) a decision which data entities are required and which data entities are optional to satisfy a quality of service (QoS) requirement, and (ii) the hierarchical parts of the respective multi-level modulation symbols that correspond to data entities required to satisfy the QoS requirement, and transmitting said feedback for only those data entities for which it has been determined that said feedback should be provided from the receiving apparatus to the transmitting apparatus to thereby satisfy said QoS requirement.