IRS Pilot Signal Sequencing for Lower-Overhead Channel Estimation
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficient channel estimation, particularly with the introduction of intelligent reflecting surfaces (IRS), which increase overhead due to the need for extensive training sequences.
Innovation Solution
A method for channel estimation in wireless communication systems using intelligent reflecting surfaces (IRS) involves receiving pilot signals and feedback signals through IRS elements, allowing for the estimation of channels while reducing overhead by configuring specific IRS elements to be turned on, utilizing sounding reference signals (SRS) and channel state information-reference signals (CSI-RS).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If extensive training sequences are used for channel estimation with IRS, then channel estimation accuracy is improved, but overhead increases proportionally to IRS size
Solution Approach 1:
The patent segments the channel estimation process into two distinct phases: direct channel estimation (without IRS) and IRS channel estimation (with IRS). By separating these estimation tasks and using different pilot signal configurations for each phase, the system avoids the need for extensive training sequences that would be required if all IRS elements were activated simultaneously, thereby reducing overhead while maintaining estimation accuracy.
Solution Approach 2:
The patent performs preliminary channel estimation between the base station and terminal before IRS channel estimation. This preliminary estimation removes the direct channel impact from subsequent measurements, allowing the system to focus training resources only on estimating the IRS channel characteristics rather than the entire composite channel, thus reducing the required overhead.
2Loss of information
If all IRS elements are activated for channel estimation, then channel estimation completeness is improved, but training sequence length increases
Solution Approach 1:
The patent divides the IRS channel estimation into multiple sequential steps: first estimating the direct channel, then using that estimation to isolate and estimate the IRS channel component. This segmentation allows complete channel information to be obtained without requiring all IRS elements to be simultaneously activated, thereby reducing the training sequence length.
Solution Approach 2:
The system performs preliminary direct channel estimation before IRS channel estimation. This preliminary action removes the direct path interference from the received signals, enabling more efficient IRS channel estimation with shorter training sequences since only the IRS-specific channel characteristics need to be estimated in the subsequent phase.
Data Source
AI summary
Disclosed herein is a base station in a wireless communication system, including receiving a first pilot signal from a terminal and estimating a channel between the terminal and the base station based on the first pilot signal, receiving a second pilot signal corresponding to an intelligent reflecting surface (IRS) element configuration from the terminal through an IRS, receiving a feedback signal of a third pilot signal corresponding to the IRS configuration from the terminal through the IRS, and estimating a channel corresponding to a specific IRS based on the first pilot signal, the second pilot signal and the third pilot signal. The second pilot signal is an uplink pilot signal, and the third pilot signal is a downlink pilot signal.