Finite-Pilot Channel-Estimation Friendliness: A New Building Wireless Performance Metric for Indoor MIMO Systems
Year: 2026
Type: article
Abstract: Building wireless performance (BWP) evaluation quantifies how layouts and materials affect indoor wireless systems at the architectural design stage. Existing BWP metrics target outcomes such as received power, capacity, delay spread, and channel hardening, while the finite-pilot cost of acquiring channel state information (CSI) in practical multiple-input multiple-output (MIMO) systems remains unexplored. This letter introduces finite-pilot channel-estimation (CE) friendliness as a new BWP metric. Adopting a deliberately tractable low-rank (rank-two specular) indoor receive covariance with line-of-sight, dominant wall-reflected, and diffuse components, we derive closed-form dominant eigenvalues and the rank-constrained finite-pilot normalized mean-square error (NMSE). The minimum training dimension$T_{\min,\mathrm {rc}}$then quantifies the pilot cost induced by building-dependent covariance. Under a separable transmit–receive covariance this dimension is set by the receive covariance, so the metric applies to the MIMO downlink and its single-stream and uplink-SIMO instances. Numerical results, including a physically grounded multi-cluster anisotropic-scattering extension, validate the analysis and show that capacity- and channel-estimation-friendly designs are generally non-equivalent: a design favoring spatial multiplexing may not minimize CSI overhead.
Source: IEEE Communications Letters
Authors: Chengfang Yue, Jieping Wu, Yang Fu
Institution: Chengdu Technological University
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,645
OpenAlex ID: W7204207487