DMRS Sequence Configuration for 5G CDM Group Index Derivation
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Solution Overview
Problem
Current 5G wireless communication systems face challenges in deriving the CDM group index and simultaneously using dynamic TRP selection with a CDM group specific cinit, while maintaining backward compatibility and efficiency in PAPR reduction for DMRS enhancements.
Innovation Solution
The method involves configuring DMRS symbol sequences based on initial seed values derived from scrambling identification and selection values, allowing dynamic selection of port options for transmission or reception on multiple CDM ports, and using a DCI channel to toggle between scrambling sequences to avoid sequence repetition and achieve low PAPR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a CDM group specific cinit is used for DMRS enhancement, then spectral efficiency is improved, but the complexity of deriving CDM group index and configuring scrambling sequences increases
Solution Approach 1:
The patent segments the DMRS configuration into multiple CDM groups, where each group can be independently configured with its own cinit value. This allows the system to derive CDM group index by dividing the total number of DMRS ports by the number of CDM groups, thereby organizing the complexity into manageable segments while maintaining spectral efficiency gains from CDM multiplexing.
Solution Approach 2:
The patent performs preliminary configuration of CDM group index and scrambling sequence parameters through higher layer signaling (RRC configuration) before actual DMRS transmission. This preliminary action allows the UE to pre-derive the CDM group index and configure the appropriate cinit values, reducing the complexity during real-time operation while enabling spectral efficiency improvements.
2Adaptability or versatility
If dynamic TRP selection is simultaneously used with CDM group specific cinit, then adaptability and network performance are improved, but the difficulty of managing multiple scrambling sequences and maintaining backward compatibility increases
Solution Approach 1:
The patent implements dynamic TRP selection by allowing the gNB to dynamically switch between different TRPs for DMRS transmission, with each TRP associated with specific CDM groups and scrambling sequences. The system dynamically selects which cinit configuration to use based on the active TRP, enabling adaptability while managing complexity through structured configuration relationships.
Solution Approach 2:
The patent creates a universal configuration framework where the same RRC configuration parameters can serve multiple functions: they define both the CDM group structure and the scrambling sequence initialization. This multi-functionality allows the system to support dynamic TRP selection and CDM group specific cinit simultaneously, while maintaining backward compatibility through a unified configuration interface that works across different release versions.
3Object-generated harmful factors
If multiple scrambling sequences are configured for different CDM groups, then PAPR reduction is achieved, but the total number of cinit configurations per UE increases
Solution Approach 1:
The patent applies local quality by assigning different cinit values specifically to different CDM groups rather than uniformly to all DMRS ports. This localized approach allows PAPR reduction to be achieved in each CDM group independently, while the total number of cinit configurations is controlled by the number of CDM groups (typically 2), rather than the total number of DMRS ports, thereby managing the quantity of configurations efficiently.
Data Source
AI summary
In an aspect, a network entity may receive download control information (DCI) indicating a first scrambling identification value, a second scrambling identification value, and a scrambling selection value, wherein the scrambling selection value has either a first scrambling selection value or a second scrambling selection value. The network entity may configure a first demodulation reference signal (DMRS) symbol sequence based on a first initial seed value, a second DMRS symbol sequence based on a second initial seed value, and a third DMRS symbol sequence based on a third initial seed value. The network entity may be configured, based on the scrambling selection value, to transmit or receive DMRS on a group of code division multiplexed (CDM) antenna ports based on either the first DMRS symbol sequence, the second DMRS symbol sequence, or the third DMRS symbol sequence.