Uplink Channel Estimation Switching for Non-Orthogonal DMRS Ports
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Solution Overview
Problem
Existing wireless communication networks face challenges in achieving accurate uplink channel estimation due to issues with DMRS configurations, leading to interference and reduced throughput, especially in scenarios with non-orthogonal DMRS ports and varying traffic loads.
Innovation Solution
A method and network entities that dynamically determine whether to use channel estimates based on current DMRS or stored reference signals, such as DMRS or SRS, based on quality-related criteria, to improve channel estimation accuracy and adapt to changing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If channel estimation is performed using current DMRS, then channel estimation can be obtained for current transmission, but accuracy deteriorates when DMRS ports are non-orthogonal or traffic load varies
Solution Approach 1:
The system performs preliminary channel estimation using stored reference signals (DMRS or SRS) received in previous time slots before actual data transmission. This preliminary estimation allows the system to prepare beamforming weights in advance and switch to current DMRS only when necessary, improving overall estimation accuracy by utilizing multiple time instances for channel characterization.
Solution Approach 2:
The system introduces stored reference signals as an intermediary source for channel estimation. Instead of relying solely on current DMRS which may be contaminated by non-orthogonal interference, the system uses previously stored reference signals that experienced different interference conditions, providing a complementary estimation source that improves accuracy when current DMRS quality is poor.
2Productivity
If beamforming weights are calculated using current DMRS, then beamforming can be performed for current slot, but throughput is reduced due to interference from non-orthogonal DMRS ports
Solution Approach 1:
The system implements a feedback mechanism where the quality of current DMRS is evaluated against stored reference signal quality. Based on this feedback comparison, the system dynamically decides whether to use current DMRS-based channel estimates or stored reference signal-based estimates for beamforming weight calculation, thereby adapting to changing interference conditions and maximizing throughput.
Solution Approach 2:
The system dynamically switches between using current DMRS and stored reference signals for channel estimation based on real-time quality assessments. This dynamic adaptation allows the system to optimize beamforming performance under varying traffic loads and interference conditions, improving throughput by selecting the best available estimation source rather than relying fixedly on current DMRS.
3Reliability
If stored channel estimates are used, then interference mitigation is improved, but adaptability to current channel conditions deteriorates
Solution Approach 1:
The system performs preliminary channel estimation using stored reference signals to establish a baseline channel characterization that is less affected by current interference. This preliminary estimation provides a stable foundation for beamforming that maintains reliability, while the system retains the option to update using current DMRS when channel conditions have genuinely changed, thus balancing adaptability with interference rejection.
Data Source
AI summary
Disclosed is a method for improved uplink channel estimation of an uplink signal received at a network node (130) connected to a plurality of antennas (131, 132) from a wireless device (140, 141). The method determines whether to determine and use a channel estimation based on a demodulation reference signal, DMRS, received with the uplink signal or whether to use a stored channel estimate instead. The determination is performed based on one or more of a quality-related criterion of the stored channel estimated and a quality-related criterion of the DMRS-based channel estimate. Hereby, the most suitable channel estimate may be used, which results in better uplink channel estimations.