Overhead signalling is signalling which contains a pilot pattern or additional information to enhance performance of the wireless networks. Examples of overhead signalling include common pilot, dedicated pilot and feedback signalling.
If the amount of overhead signalling is large, the performance of the transmission and reception for each symbol can be increased whereas the system performance can be degraded once the amount of overhead signalling is used larger than the certain threshold. For the extreme example, if overhead signalling consumes the whole system transmission time and spectrum the system throughput becomes zero because of no remained time to transmit desired information signal.