NR PDCCH and LTE CRS Coexistence via Puncture Signaling
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Solution Overview
Problem
Current 3GPP specifications do not allow NR PDCCH to overlap with LTE CRS, limiting NR PDCCH capacity in dynamic spectrum sharing deployments, which restricts the potential for higher NR PDCCH performance and capacity.
Innovation Solution
The proposed solution involves using puncture and superposition signalling to enable the transmission of LTE CRS and NR PDCCH during the same OFDM symbol and frequency domain resource elements, with the network node determining a puncture threshold for NR PDCCH based on the UE's capability to support puncture signalling, allowing for flexible power management and interference mitigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If NR PDCCH is allowed to overlap with LTE CRS, then NR PDCCH capacity is improved, but interference between the two signals increases
Solution Approach 1:
The patent applies local quality by making different parts of the NR PDCCH signal have different properties. Specifically, it uses puncture thresholds and aggregation levels to create different signal characteristics in different resource elements, allowing some REs to be punctured (set to zero) while others maintain full power, thereby coexisting with LTE CRS in the same time-frequency resources without causing harmful interference
Solution Approach 2:
The patent changes key parameters of the NR PDCCH transmission including puncture thresholds, aggregation levels, and power levels. By dynamically adjusting these parameters based on LTE CRS presence and UE capability, the system enables NR PDCCH to share spectrum with LTE CRS while controlling interference through parameter optimization
2Productivity
If puncture signalling is used to enable NR PDCCH and LTE CRS coexistence, then NR PDCCH capacity is enhanced, but signal complexity increases
Solution Approach 1:
The patent introduces dynamic puncture thresholds and aggregation levels that can be adjusted based on channel conditions, LTE CRS configuration, and UE capability. This dynamic approach allows the system to optimize NR PDCCH capacity while managing complexity adaptively rather than using fixed complex signal structures
Solution Approach 2:
The patent performs preliminary actions by determining puncture thresholds and aggregation levels before actual NR PDCCH transmission. The network node pre-calculates which resource elements should be punctured based on expected LTE CRS positions, allowing the UE to efficiently decode PDCCH by knowing in advance which REs to expect as punctured, thereby reducing real-time processing complexity
Data Source
AI summary
This disclosure presents processes for improving the quality of NR PDCCH reception at a UE when transmitted in a same orthogonal frequency-division multiplexing (OFDM) symbol and a same frequency domain resource element as an LTE CRS. Using a capability parameter of the UE, a network node can transmit an LTE CRS and NR PDCCH in the same OFDM symbol and the same frequency domain resource elements using various encoding schemes. The encoding schemes can be one or more of puncture signalling, superposition signalling, relative power levels, UE type, adjusting the AL of the LTE CRS, or various combinations thereof. The UE can decode the PDDCH using the encoding scheme. Legacy UEs can be supported with this disclosure by the network node selecting supported UE capabilities for the encoding. The network node can balance transmission reliability with available resources.