DM-RS Combining for Wireless Channel Estimation
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Solution Overview
Problem
Traditional wireless communication systems face challenges in combining different types of reference signals due to varying precoding applied to demodulation reference signals (DM-RS), which limits their flexibility and efficiency, especially for advanced mobile devices with different timing characteristics.
Innovation Solution
The system configures wireless communications networks to allow user equipment (UE) to combine multiple DM-RSs for demodulating physical downlink shared channels and other downlink transmissions by using explicit or implicit signaling to determine combinable reference signals, enabling UE-specific and control channel reference signals to be combined across multiple transmission time intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple DM-RS are combined across transmission time intervals, then channel estimation accuracy is improved, but device complexity increases due to different timing characteristics and precoding variations
Solution Approach 1:
The patent changes the timing parameters of DM-RS transmissions to align different services (e.g., eMBB and URLLC) to a common timing grid. This parameter adjustment enables reference signals from different services to be combined at the receiver without requiring complex timing adjustments, thereby improving channel estimation accuracy while controlling device complexity
Solution Approach 2:
The patent segments the timing structure into common reference signal occasions that can be shared across multiple services. By dividing the transmission time intervals into segments with aligned DM-RS positions, the system enables selective combining of reference signals from different services, improving measurement precision without overwhelming device processing capabilities
2Quantity of substance
If DM-RS transmissions are reduced through combining, then pilot overhead is decreased, but reliability deteriorates due to potential precoding differences
Solution Approach 1:
The patent modifies transmission parameters including precoding consistency across combined DM-RS instances. By ensuring that precoding remains consistent or can be properly accounted for when combining reference signals, the system reduces pilot overhead while maintaining the reliability needed for accurate channel estimation
Solution Approach 2:
The patent implements feedback mechanisms where the receiver provides information about precoding conditions and timing alignment to the transmitter. This feedback enables the system to adjust DM-RS transmissions to be combinable while maintaining reliability, thereby reducing overall pilot overhead in the system
Data Source
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AI summary
Techniques are provided for combining different types of reference signals. A wireless communications network may be configured to allow a user equipment (UE) to combine multiple demodulation reference signals (DM-RSs) to support demodulation of a physical downlink shared channel (PDSCH), and/or other downlink transmissions, transmitted from a base station to the UE. The base station may provide explicit signaling that reference signals transmitted in two or more transmission time intervals may be combined, or a determination that reference signals transmitted in two or more transmission time intervals may be combined may be made implicitly based on system configuration and previous transmissions. Based on the explicit signaling and/or implicit determination, a UE may combine reference signals included in each of two or more reference signals for use in demodulation of downlink transmissions.