5G Base Station DMRS CDM Group Adaptation
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Solution Overview
Problem
In high-frequency bands, beamforming in 5G communication systems faces challenges with reliability, frequency utilization efficiency, and throughput due to channel cutoffs caused by obstacles and high spatial correlation in Line of Sight environments.
Innovation Solution
A base station and terminal apparatus configuration that includes a signal detection unit to demodulate downlink shared channels using downlink control information, which indicates antenna port numbers and code division multiplexing groups for demodulation reference signals, considering power ratios and scrambling identities to improve communication reliability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If beamforming is used in high frequency bands to compensate for path loss, then path loss is compensated, but reliability may deteriorate due to channel cutoff caused by blocking
Solution Approach 1:
The patent segments the downlink shared channel into multiple code division multiplexing groups, each associated with different demodulation reference signal ports. This segmentation allows the system to selectively use different reference signal ports for channel estimation, providing diversity against blocking effects and improving reliability while maintaining beamforming benefits.
Solution Approach 2:
The patent introduces downlink control information that dynamically indicates the number of CDM groups and antenna port numbers, allowing the system to adapt parameters based on channel conditions. This parameter change capability enables switching between different reference signal configurations to mitigate blocking effects while maintaining efficient beamforming operation.
2Loss of energy
If beamforming is used in high frequency bands, then path loss is compensated, but frequency utilization efficiency may deteriorate
Solution Approach 1:
The patent creates a universal framework where a single downlink shared channel can be efficiently demodulated using multiple different reference signal port configurations. The CDM group structure allows the same physical channel to benefit from both beamforming gain and diversified channel estimation approaches, improving frequency utilization efficiency without sacrificing path loss compensation.
Solution Approach 2:
The system dynamically selects the number of CDM groups and antenna port configurations based on downlink control information, adapting to changing channel conditions. This dynamic approach allows optimal frequency utilization by adjusting the complexity of reference signal multiplexing to match actual communication requirements, preventing unnecessary overhead while maintaining beamforming efficiency.
3Loss of energy
If beamforming is used in high frequency bands, then path loss is compensated, but throughput may deteriorate due to high spatial correlation in Line of Sight environments
Solution Approach 1:
By segmenting the reference signal structure into multiple CDM groups with different antenna ports, the patent reduces the impact of high spatial correlation. Different ports experience independently faded channels, and the system can select the most reliable port for demodulation, thereby maintaining higher throughput in LOS conditions where traditional single-port beamforming would suffer from rank deficiency.
Solution Approach 2:
The downlink control information dynamically adjusts the number of active CDM groups and antenna port assignments based on spatial correlation conditions. In high correlation environments, the system activates multiple ports to exploit available diversity, while in low correlation environments, it can use fewer ports to reduce overhead, thus optimizing throughput across different propagation conditions while maintaining path loss compensation.
Data Source
AI summary
A terminal apparatus for communicating with a base station apparatus, the terminal apparatus including: a receiver configured to receive downlink control information and a downlink shared channel; and a signal detection unit configured to demodulate the downlink shared channel (PDSCH) by using the downlink control information, wherein the downlink control information includes information for indicating an antenna port number and the number of code division multiplexing (CDM) groups for a demodulation reference signal (DMRS), each of the CDM groups indicates a DMRS port to be multiplexed by CDM, the PDSCH is demodulated in consideration of a power ratio of the DMRS and the PDSCH, and whether or not to consider powers of the DMRS and the PDSCH, based on the number of the CDM groups, is determined based on the downlink control information.