Dynamic Precoding Shared Reference Signals 5G
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G, face challenges in efficiently managing different robustness and layer requirements for data and control channels, leading to increased overhead when using separate demodulation reference signals for closely located or intermingled control and data channels.
Innovation Solution
The use of a single set of terminal-specific demodulation reference signals with dynamic precoding, where a virtual-antenna-to-physical-antenna mapper generates and transmits these signals, allowing for efficient beam-forming of both data and control channels using a unified set of symbols-to-virtual-antenna mappers, which are selected based on the propagation channels to create effective multi-layer spatial layers for transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate demodulation reference signals are used for data and control channels, then the specific robustness and layer requirements of each channel can be met, but the overhead increases significantly
Solution Approach 1:
The patent merges the demodulation reference signals for data channels and control channels into a single unified reference signal. Instead of transmitting separate reference signals for each channel type, the invention combines them into one shared reference signal that serves both purposes, thereby reducing the total number of pilot resources while maintaining the ability to meet different robustness requirements through dynamic precoding.
Solution Approach 2:
The unified demodulation reference signal is designed to serve multiple functions simultaneously - it acts as the reference signal for both data channel demodulation and control channel demodulation. This multi-functional approach allows a single reference signal to replace what would traditionally require multiple separate reference signals, reducing overhead while maintaining reliability.
2Adaptability or versatility
If dynamic precoding is applied to a single set of reference signals, then resource allocation flexibility is improved, but the complexity of selecting appropriate symbols-to-virtual-antenna mappers increases
Solution Approach 1:
The patent implements dynamic precoding where the symbols-to-virtual-antenna mappers are selected dynamically based on channel conditions and transmission requirements. Rather than using fixed mappers, the system adapts the mapper selection in real-time to optimize performance for different channel states, transmission ranks, and robustness requirements, thereby achieving high resource allocation flexibility.
Solution Approach 2:
The invention changes the parameters of the precoding operation by selecting different symbols-to-virtual-antenna mappers based on varying channel conditions. The system adjusts the mapper parameters dynamically to match the current transmission requirements, allowing flexible resource allocation while managing complexity through standardized mapper options.
Data Source
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AI summary
A receiver apparatus receives a terminal-specific demodulation reference signal having a rank k and estimates an effective multi-layer channel response, using the received terminal-specific demodulation reference signal. The receiver demodulates first data symbols from first time- frequency resource elements, using the estimate of the effective multi-layer channel response and using a first symbols-to-virtual-antenna mapping matrix M to obtain nc modulation symbols from each of the first time-frequency resource elements, wherein nc > 1 and wherein the first symbol- to-transmit-layer mapping matrix M has dimensions k by nc. The first data symbols are decoded to obtain downlink control information assigning second time-frequency resource elements to the receiver. The receiver demodulates second data symbols from the second time-frequency resource elements, using the estimate of the effective multi-layer channel response, to obtain nd modulation symbols from each of the second time-frequency resource elements, wherein 1 < nd < k. The second data symbols are decoded.