Covering-radius and Collinearity- Minimizing Pilots for Channel Estimation in TDD Systems
This addresses channel estimation efficiency for TDD communication systems, but it appears incremental as it refines existing pilot design principles under specific constraints.
The paper tackles pilot design for channel estimation in TDD systems by proposing a geometry-aware pattern that balances grid coverage and collinearity suppression, showing that the MCC pattern improves recovery performance in numerical results.
This letter studies pilot design for orthogonal frequency-division multiplexing-based time-division duplex (TDD) systems under a sliding-window latest-slot recovery framework that jointly exploits delay--Doppler sparsity across recent slots. Under contiguous-subband and fairness constraints, this viewpoint naturally leads to a geometry-aware time--frequency joint pilot assignment. We show that effective patterns should balance grid coverage and redundant-collinearity suppression, with an additional symmetry-avoidance refinement when complete collinearity elimination is infeasible. Based on these principles, we formulate a mixed-integer construction method compatible with practical TDD allocation. Numerical results show that minimum-coverage-radius and collinearity-control (MCC) pattern improves both surrogate geometry metrics and latest-slot recovery performance.