Reference Signal Port Configuration for Random Access Reliability
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Solution Overview
Problem
Current 5G NR wireless communication systems face performance degradation due to higher subcarrier spacing and increased sensitivity to channel estimation errors, particularly with code-division multiplexed demodulation reference signals (DMRS) ports, limiting the versatility in transmitting random access messages.
Innovation Solution
Configuring multiple reference signal ports for user equipment (UE) to transmit random access messages, allowing for multiplexing and improving reliability by selecting appropriate ports based on parameters such as modulation and coding schemes, delay spread, and subcarrier spacing, and indicating these ports in the random access response message.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If code-division multiplexed DMRS ports are used for random access messages, then multiplexing capability is improved, but performance degrades due to higher subcarrier spacing and increased sensitivity to channel estimation errors
Solution Approach 1:
The patent implements dynamic selection of DMRS port types (type 1 or type 2) and configurations based on current channel conditions, subcarrier spacing, and random access message requirements. The system can adaptively switch between code-division multiplexed ports and other port types, adjusting the DMRS configuration in real-time to optimize both multiplexing capability and channel estimation accuracy for each specific transmission scenario.
Solution Approach 2:
The patent changes key parameters including DMRS port type (1 or 2), port index, cyclic shift values, and orthogonal cover code configurations to resolve the contradiction. By modifying these parameters based on subcarrier spacing and channel conditions, the system can maintain reliable channel estimation while enabling multiplexing of multiple random access messages when conditions permit.
2Adaptability or versatility
If multiple reference signal ports are configured for random access messages, then versatility in transmitting random access messages is improved, but device complexity increases
Solution Approach 1:
The patent pre-configures multiple DMRS port options (type 1 and type 2 with various port indices) and stores them in the UE for later selection. This preliminary configuration allows the system to have versatile transmission capabilities ready in advance, while the actual selection process remains simple and can be performed based on straightforward criteria such as subcarrier spacing values or random access occasion indices, avoiding complex real-time decisions.
3Measurement precision
If DMRS port selection is based on multiple parameters (modulation and coding schemes, delay spread, subcarrier spacing), then channel estimation accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent implements a dynamic parameter selection mechanism where the DMRS port configuration is adapted based on current channel conditions including delay spread estimates, subcarrier spacing, and modulation and coding schemes. The system continuously monitors these parameters and adjusts the DMRS port selection accordingly, allowing high precision channel estimation under varying conditions without requiring manual reconfiguration.
Solution Approach 2:
The system uses feedback from channel quality indicators, successful random access outcomes, and error rates to refine DMRS port selections. By monitoring the effectiveness of different port configurations and adjusting future selections based on this feedback, the system achieves high channel estimation accuracy while keeping processing complexity manageable through learned patterns rather than exhaustive analysis of all parameters in every decision.
Data Source
AI summary
Aspects described herein relate to a user equipment (UE) determining a reference signal port of multiple configured reference signal ports to use in transmitting a reference signal for a random access message. In one aspect, a configuration indicating multiple reference signal ports to use in transmitting reference signals for a random access message can be transmitted to the UE, as well as an indication of a reference signal port of the multiple reference signal ports to be used in transmitting a reference signal for the random access message.