NR PDCCH DMRS Resource Shifting for LTE Interference Avoidance
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Solution Overview
Problem
The coexistence of LTE and NR systems in the same frequency band leads to severe interference from LTE reference signals, particularly CRS, PHICH, and PCFICH, which limits the performance and capacity of the NR PDCCH, affecting scheduling flexibility.
Innovation Solution
A method for determining candidate REs for NR DMRS by shifting around LTE reference signals such as CRS, PCFICH, and PHICH to avoid interference, allowing detection and reception on available REs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LTE reference signals (CRS, PHICH, PCFICH) are transmitted in the same frequency band as NR PDCCH, then LTE system coverage and reference signal transmission are maintained, but severe interference is caused to NR PDCCH, reducing its capacity and performance
Solution Approach 1:
The patent extracts the harmful LTE reference signals (CRS, PHICH, PCFICH) from the frequency resources used by NR PDCCH. By identifying and excluding these interfering signals from the resource element selection, the NR PDCCH can be transmitted on remaining clean resources, thereby resolving the interference problem while maintaining LTE reference signal transmission elsewhere in the frequency band.
Solution Approach 2:
The patent applies local quality by differentiating the treatment of different resource elements within the frequency band. Instead of uniformly avoiding all LTE signals, the method specifically identifies and excludes only the harmful reference signal resources (CRS, PHICH, PCFICH) from NR PDCCH transmission, while allowing NR PDCCH to utilize other frequency resources that do not conflict with LTE signals.
2Productivity
If NR PDCCH transmits on resource elements occupied by LTE reference signals, then NR system capacity and scheduling flexibility are improved, but interference from LTE signals degrades PDCCH performance
Solution Approach 1:
The patent applies preliminary action by pre-identifying and pre-excluding the resource elements occupied by LTE reference signals (CRS, PHICH, PCFICH) before NR PDCCH transmission. The terminal determines the resource element locations of LTE reference signals in advance and uses this information to select appropriate resource elements for NR PDCCH, ensuring that interfering resources are avoided from the outset.
Solution Approach 2:
The patent uses the knowledge of LTE reference signal resource element locations as an intermediary factor to guide NR PDCCH resource selection. The terminal leverages this intermediate information (LTE RE locations) to make informed decisions about which resources to use for NR PDCCH, thereby mediating between the need for high capacity and the need to avoid interference.
3Object-affected harmful factors
If the terminal determines candidate REs by shifting around LTE reference signals, then interference avoidance is achieved, but the complexity of signal reception processing increases
Solution Approach 1:
The patent applies parameter changes by systematically varying the resource element indices to generate candidate REs. The terminal modifies the original RE locations by adding offset values (e.g., +1, -1, +2, -2) to create shifted candidate REs. This parameter-based approach provides a structured method for interference avoidance that, while increasing processing complexity, follows a predictable and manageable pattern.
Data Source
AI summary
The present disclosure provides a method and apparatus for receiving signals and for sending signals, and a storage medium. The method for receiving signals comprises: determining first initial resource elements (REs) corresponding to a first demodulation reference signal (DMRS) of a downlink control channel (PDCCH) of a first system; determining second initial REs corresponding to a reference signal of a second system; on the basis of the first initial RE, determine candidate REs corresponding to the first DMRS by shift; where resources corresponding to the first initial RE and the second initial RE are identical; and detecting and receiving the first DMRS on available REs of the candidate REs; where the available REs are unoccupied by another reference signal, and the another reference signal is a second DMRS or the reference signal of the second system.