DMRS Pattern Allocation for NCT Carrier Downlink
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Solution Overview
Problem
In LTE systems, the introduction of a new carrier type (NCT) leads to poor downlink transmission performance due to the existing DMRS pattern being used on both backward compatible and non-backward compatible carriers, which restricts the transmission of control channels and data channels, resulting in suboptimal resource allocation.
Innovation Solution
A method to determine different DMRS patterns based on the priorities of channels and signals in the downlink transmission process, allowing for concurrent use of multiple DMRS patterns on an NCT carrier, optimizing resource unit allocation by using distinct DMRS patterns for subframes with and without specific signals, and adjusting based on overlapping frequency bands and channel types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single DMRS pattern is used on both backward compatible and non-backward compatible carriers, then device compatibility is maintained, but downlink transmission performance deteriorates due to suboptimal resource allocation
Solution Approach 1:
The patent segments the DMRS patterns into at least two distinct patterns: a first DMRS pattern for backward compatible carriers and a second DMRS pattern for non-backward compatible carriers. This segmentation allows each carrier type to use the optimal DMRS pattern for its specific requirements, resolving the contradiction between maintaining compatibility and improving transmission performance.
Solution Approach 2:
The patent applies different DMRS patterns to different carrier types based on their specific characteristics. Backward compatible carriers use the first DMRS pattern while non-backward compatible carriers use the second DMRS pattern, allowing each local system to have the quality and properties best suited to its specific needs rather than forcing a uniform solution.
2Loss of information
If control channels are transmitted in the first four symbols of a subframe, then control information coverage is ensured, but DMRS transmission is restricted in this region, reducing data channel performance
Solution Approach 1:
The patent implements dynamic DMRS pattern selection where the DMRS pattern can change based on the subframe type and carrier configuration. In subframes where control channels are present, the system dynamically adjusts the DMRS pattern to avoid conflicting with control channel resources, while in other subframes it can use patterns optimized for data transmission, thus dynamically balancing control and data performance.
Solution Approach 2:
The patent resolves the resource conflict by utilizing different time-frequency resource dimensions. The first DMRS pattern is designed to coexist with control channels in the time domain, while the second DMRS pattern optimizes for data transmission scenarios. This dimensional approach allows the system to allocate resources in multiple dimensions rather than being constrained to a single fixed pattern.
3Ease of manufacture
If a centralized DMRS pattern is used only on rear symbols of subframes, then implementation simplicity is maintained, but resource allocation flexibility is reduced, limiting optimization potential
Solution Approach 1:
The patent creates a universal DMRS pattern selection mechanism that can adapt to multiple carrier types and transmission scenarios. The system maintains multiple DMRS patterns and selects the appropriate one based on the carrier type and subframe configuration, making the overall system multi-functional and adaptable to different requirements while keeping the implementation framework unified and manageable.
Data Source
AI summary
A downlink channel decoding method, a downlink information transmission method, a user equipment, and a base station are provided. The downlink channel decoding method includes: determining, by a user equipment, a resource unit occupied by a DMRS; and decoding a downlink channel based on the DMRS transmitted on the resource unit. The present invention can enable different DMRS patterns to concurrently exist on an NCT carrier. In a downlink transmission process, a DMRS pattern used for downlink transmission is determined according to priorities of different channels and/or signals, which can ensure optimal performance of a high-priority channel and/or signal, and can further improve downlink transmission performance.