Downlink Reference Signal Transmit Port Configuration
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Solution Overview
Problem
In Massive MIMO technology, the high feedback overhead of precoding matrices determined by terminal devices poses a challenge, and properly configuring the transmit ports of downlink reference signals is essential to reduce interference and improve signal quality.
Innovation Solution
A method for configuring the transmit ports of downlink reference signals, where a network device provides different configurations based on delay information, allowing for optimal precoding resource bundling granularity, subband size, and pilot density for each transmit port, thereby facilitating accurate channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal device determines a precoding matrix based on downlink channel measurement and feeds back spatial domain vectors, frequency domain vectors, and weighting coefficients, then the network device can obtain a precoding matrix that is the same as or similar to the terminal device's precoding matrix, but the feedback overhead becomes relatively high
Solution Approach 1:
The patent extracts only the essential delay information from the full channel state information that would otherwise need to be fed back. By identifying and transmitting only the delay parameters that characterize the channel, the system achieves precoding matrix alignment between terminal and network device while dramatically reducing feedback overhead.
Solution Approach 2:
The patent transforms the feedback from transmitting complex precoding matrix parameters (spatial domain vectors, frequency domain vectors, weighting coefficients) to transmitting simplified delay parameters. This parameter transformation maintains the essential channel characteristics needed for precoding while reducing the dimensionality and overhead of feedback.
2Loss of information
If the network device precodes a downlink reference signal based on delay and angle obtained from uplink channel estimation, then feedback overheads of the terminal device are reduced, but the configuration of transmit ports becomes complex
Solution Approach 1:
The patent applies different configurations (such as different precoding resource bundling granularities) to different transmit ports based on their specific delay information. Instead of using a uniform configuration for all ports, the system tailors the configuration to match the local channel characteristics of each port, optimizing performance while managing complexity.
Solution Approach 2:
The patent segments the transmit ports into different groups based on their delay information characteristics. By dividing the ports according to their delay profiles, the network device can apply appropriate configurations to each segment, making the overall configuration more manageable and systematic.
3Measurement precision
If different configurations are provided for various transmit ports based on different delay information, then channel estimation accuracy is improved, but the system complexity increases
Solution Approach 1:
The patent performs preliminary classification of transmit ports based on delay information before channel estimation. By pre-grouping ports with similar delay characteristics and assigning appropriate configurations in advance, the system simplifies the subsequent channel estimation process while maintaining high accuracy for each port group.
Data Source
AI summary
Example methods and apparatus for configuring a transmit port of a downlink reference signal are described. One example method includes indicating configurations corresponding to a plurality of transmit ports to a terminal device by a network device by using first indication information. Each transmit port may be associated with one piece of delay information, transmit ports associated with same delay information correspond to a same configuration, and at least two transmit ports associated with different delay information correspond to different configurations. The terminal device may receive, based on a configuration corresponding to each transmit port, downlink reference signals sent by the plurality of transmit ports.