End-to-end communication impact of pilot optimization

Characterize rigorously how unitary pilot optimization and the associated simplification of the communication-block transformation affect channel-estimation accuracy and end-to-end communication performance, including achievable communication rate, in practical DBU-OFDM systems.

Background

The proposed DBU-OFDM architecture applies unitary transformations to pilot, communication, and sensing resources to shape ambiguity sidelobes while preserving resource isolation and signal energy. In the ablation study, the learned communication transformation is approximately monomial, and the authors observe that setting the communication block to the identity appears to preserve effective sidelobe suppression under the considered configuration.

However, pilot optimization changes the effective pilot amplitudes and phases, which may influence channel estimation even though total pilot energy is preserved. The paper does not rigorously quantify the resulting channel-estimation effects or the end-to-end communication consequences, including achievable communication rate. It explicitly leaves this characterization unresolved.