Date Added: Dec 2009
To achieve multiuser diversity gains, resource allocation relies on accurate and timely feedback of the users' channel states. Obtaining such reliable feedback under tight overhead and delay constraints is nontrivial in many wireless systems. To this end, the users cooperate when transmitting feedback. Studying the authors cooperative feedback scheme exemplarily for the multiuser OFDM downlink shows that it efficiently avoids resource allocation errors. This significantly improves the error rate, ergodic sum capacity, or the system's energy efficiency even if the resources and energy required for cooperation are taken into account.