On the Gain of Joint Processing of Pilot and Data Symbols in Stationary Rayleigh Fading Channels

In many typical mobile communication receivers, the channel is estimated based on pilot symbols to allow for a coherent detection and decoding in a separate processing step. Currently, much work is spent on receivers which break up this separation, e.g., by enhancing channel estimation based on reliability information on the data symbols. In this paper, we evaluate the possible gain of a joint processing of data and pilot symbols in comparison to the case of a separate processing in the context of stationary Rayleigh flat-fading channels. Therefore, we discuss the nature of the possible gain of a joint processing of pilot and data symbols. We show that the additional information that can be gained by a joint processing is captured in the temporal correlation of the channel estimation error of the solely pilot-based channel estimation, which is not retrieved by the channel decoder in case of separate processing. In addition, we derive a new lower bound on the achievable rate for joint processing of pilot and data symbols. Finally, the results are extended to multiple-input multiple-output channels.