NR PDCCH Reception Adaptation to LTE CRS Interference
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Solution Overview
Problem
The coexistence of Long Term Evolution (LTE) and New Radio (NR) systems on the same spectrum leads to interference, as LTE systems continuously transmit Cell-specific Reference Signals (CRSs), which conflict with NR Physical Downlink Control Channels (PDCCHs), limiting the receiving manner to a fixed approach.
Innovation Solution
The proposed solution involves determining a receiving manner for receiving NR PDCCHs when an LTE CRS conflict is detected, allowing terminals to adapt their receiving methods dynamically. This includes puncturing or rate matching based on the conflicting resource elements, enabling flexible reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LTE systems continuously transmit Cell-specific Reference Signals (CRSs), then LTE system reliability is maintained, but NR PDCCH reception is interfered with
Solution Approach 1:
The patent applies local quality by differentiating the handling of resource elements based on their specific characteristics. Instead of uniformly treating all CRS resources as harmful, the system identifies and isolates only the specific REs occupied by LTE CRS, allowing NR PDCCH to be transmitted on non-conflicting REs while maintaining LTE CRS transmission. This localized approach resolves the contradiction by preserving LTE reliability where needed while enabling NR reception where possible.
Solution Approach 2:
The patent segments the resource elements into distinct sets: those occupied by LTE CRS and those available for NR PDCCH. By dividing the frequency-time resource grid into these segments, the system can simultaneously support both LTE CRS transmission and NR PDCCH reception without mutual interference. The segmentation allows the terminal to selectively receive PDCCH on non-conflicting REs while LTE continues transmitting CRS on its designated REs.
2Device complexity
If a fixed receiving manner is used for NR PDCCH, then terminal complexity is reduced, but adaptability to interference is limited
Solution Approach 1:
The patent implements dynamics by enabling the terminal to adapt its receiving manner based on the detected interference conditions. Instead of using a fixed receiving method, the terminal dynamically determines whether to receive PDCCH on conflicting REs or to skip those REs based on the presence of LTE CRS. This dynamic adjustment mechanism increases adaptability while maintaining reasonable complexity through automated detection and selection processes.
Solution Approach 2:
The patent changes the receiving parameters dynamically based on interference conditions. The terminal adjusts parameters such as which REs to monitor, which symbols to decode, and how to map PDCCH candidates based on the detected LTE CRS configuration. This parameter change approach allows the same terminal to adapt to different interference scenarios without requiring multiple fixed receiving modes, thus improving versatility while managing complexity.
3Productivity
If NR PDCCH is transmitted on resource elements conflicting with LTE CRS, then spectrum utilization is improved, but reception reliability deteriorates
Solution Approach 1:
The patent applies partial action by transmitting NR PDCCH only on the subset of resource elements that do not conflict with LTE CRS, rather than attempting to utilize all available REs uniformly. This partial transmission approach maximizes spectrum utilization for PDCCH while ensuring reception reliability on the non-conflicting REs. The system accepts that not all REs can be used for PDCCH when LTE CRS are present, but optimizes the use of available safe REs.
Data Source
AI summary
A physical downlink control channel receiving method is performed by a terminal. The method includes: in response to determining that a Long Term Evolution Cell-specific Reference Signal (LTE CRS) conflicts with a New Radio Physical Downlink Control Channel (NR PDCCH), determining a receiving manner for receiving the NR PDCCH; and receiving the NR PDCCH according to the receiving manner.