On the Impact of Channel State Information Quantization and Feedback in Practical OFDM Implementation

In Orthogonal Frequency Division Multiplexing (OFDM), channel knowledge can be exploited to implement adaptive solutions based on bit-loading to improve the communication performance. Typically, channel estimation is performed at the receiver, with the resulting information being sent back to the transmitter to drive bit-loading. However, feedback information is subject to quantization, with the related errors potentially causing unreliable OFDM adaptation. Therefore, we investigate the impact of information quantization on the transmission efficiency, considering different strategies for feedback signaling. Performance are evaluated by referring to four propagation scenarios, that are radio-frequency, optical, powerline and underwater acoustic channels.