Front-loaded DMRS Mapping Rule for Wireless User Terminal
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Solution Overview
Problem
In next-generation mobile communication systems, the Front-loaded DMRS collides with the control channel when time direction Bundling is applied due to a non-constant size of the control channel in each slot, leading to interference issues.
Innovation Solution
A user terminal is designed with a reception section to receive downlink signals, a control section to demap the control channel and Front-loaded DMRS, and a channel estimation section that computes channel estimation values, with the Front-loaded DMRS mapped rearward of the control channel in the first slot, ensuring it does not collide with the control channel in subsequent slots based on a specified mapping rule.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the Front-loaded DMRS is mapped to a fixed symbol in each slot independently from the control channel position, then the mapping configuration is simple and fixed, but the Front-loaded DMRS collides with the control channel in subsequent slots when time direction Bundling is applied
Solution Approach 1:
The patent applies dynamics by making the Front-loaded DMRS mapping position flexible rather than fixed. The mapping position is dynamically adjusted based on the control channel position in each slot, allowing the system to adapt to varying control channel sizes while preventing collisions. This is achieved by configuring the Front-loaded DMRS to be mapped to a symbol that is a predetermined number of symbols after the control channel in each slot, rather than using a fixed symbol position across all slots.
2Measurement precision
If the Front-loaded DMRS is mapped to a symbol immediately after the control channel in the first slot, then the mapping is optimized for the first slot, but the Front-loaded DMRS collides with the control channel in the second or subsequent slot due to non-constant control channel size
Solution Approach 1:
The patent applies local quality by allowing different mapping configurations for the Front-loaded DMRS in different slots. Specifically, the mapping position is determined locally based on the control channel position in each individual slot, rather than using a uniform mapping rule across all slots. This enables the system to optimize for each slot's specific conditions while preventing collisions in subsequent slots with varying control channel sizes.
Solution Approach 2:
The patent applies preliminary action by pre-configuring the mapping rule that determines the Front-loaded DMRS position based on the control channel position. The system预先 establishes the relationship that the Front-loaded DMRS should be mapped to a predetermined number of symbols after the control channel, which prevents potential collisions before they occur in subsequent slots with different control channel sizes.
Data Source
AI summary
Provided is a user terminal to be used in a future wireless communication system which bundles a plurality of slots (sub-frames) in a time direction. When applying bundling, a Front-loaded DMRS (Demodulation Reference Signal) is mapped to the rear of a control channel in a leading slot, and in second and subsequent slots, mapping is carried out on the basis of a rule to prevent conflict between the Front-loaded DMRS and the control channel. A control unit (203) of a user terminal (20) stipulates, in second and subsequent slots, the mapping configuration of the Front-loaded DMRS (the existence of mapping and/or the mapping position) on the basis of the aforementioned rules.