Cooperative feedback to improve capacity and error rate in multiuser diversity systems — An OFDM case study

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 non-trivial in many wireless systems. To this end, we let multiple users cooperate when transmitting feedback. Studying our cooperative feedback scheme exemplarily for the multiuser OFDM downlink shows that it efficiently avoids resource allocation errors. This significantly improves error rate and ergodic sum capacity even if overhead is taken into account.