Multicast QCL State Management in 5G NR Terminals
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Solution Overview
Problem
In 5G NR radio communication systems, determining quasi-colocation (QCL) for multicast PDSCH is challenging due to varying QCL with the minimum CORESET ID for each UE, making it difficult to establish a common QCL state across multiple terminals.
Innovation Solution
A radio communication system and method that assumes quasi-colocation of the downlink data channel as a specific common state among multiple terminals when specific conditions are met, using a control unit to manage group-common PDSCH and PDCCH, allowing for simultaneous data transmission to multiple terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the QCL with the minimum CORESET ID for the latest monitoring slot is used to receive PDSCH, then the reception timing is improved, but the QCL state varies for each UE making group-common reception impossible
Solution Approach 1:
The patent segments the QCL determination by introducing a flag field that distinguishes between unicast and multicast QCL assumptions. When the flag indicates multicast, a common QCL state is used for all UEs in the group, while unicast QCL can still be used individually. This segmentation allows simultaneous support for both UE-specific optimized reception and group-common reception.
Solution Approach 2:
The flag field acts as an intermediary mechanism that mediates between the conflicting requirements of UE-specific QCL optimization and group-common QCL assumption. By setting this flag, the system can switch between different QCL determination modes, enabling the gNB to control whether UEs use their individual minimum CORESET ID QCL or a common multicast QCL state.
2Reliability
If UE-specific QCL determination is used, then individual UE reception performance is improved, but simultaneous data transmission to multiple terminals cannot be achieved
Solution Approach 1:
The patent introduces dynamic switching capability between UE-specific QCL and common QCL modes through the flag field. The system can dynamically adapt the QCL determination method based on whether multicast or unicast reception is intended, allowing flexible optimization for different service scenarios while maintaining both individual performance and group transmission capabilities.
Solution Approach 2:
The flag field mechanism provides universal applicability, enabling the same PDSCH reception process to support both unicast and multicast scenarios. When the flag indicates unicast, UE-specific QCL is applied for optimal individual performance; when indicating multicast, a common QCL state is applied for group transmission, thus achieving multi-functionality in a unified framework.
Data Source
AI summary
A terminal receives a downlink data channel common to a group of terminals in data distribution for a plurality of terminals. The terminal assumes that the quasi collocation of the downlink data channel is a specific state common to a plurality of terminals when a specific condition is satisfied.