LTE PDCCH and PRS Resource Conflict Resolution
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Solution Overview
Problem
In LTE systems, the transmission of PDCCH data over the first four OFDM symbols conflicts with positioning reference signals (PRSs) due to semi-static CRS configuration, limiting UE positioning precision and system performance.
Innovation Solution
The method involves sending PDCCH data over the first n OFDM symbols in a subframe, with n being 2 or 3 for non-MBSFN subframes with a normal cyclic prefix and less than or equal to 10 resource blocks, ensuring PRSs and PDCCH data are not transmitted on the same physical resource, or having the receiving end ignore one of them, thereby avoiding conflicts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PDCCH data is transmitted over the first four OFDM symbols in a subframe, then control channel coverage is improved, but conflict with positioning reference signals occurs
Solution Approach 1:
The patent segments the OFDM symbols into different groups based on their function. Control symbols (for PDCCH) and reference signal symbols (for PRS) are separated into distinct time-frequency resources. This segmentation prevents overlap between control data and positioning reference signals, resolving the conflict while maintaining control channel coverage.
Solution Approach 2:
The patent resolves the conflict by utilizing different dimensions of the time-frequency resource grid. Instead of allowing overlap in the same time-frequency resources, the solution assigns PDCCH and PRS to different symbol indices within the subframe structure, effectively using the time dimension to separate conflicting signals.
2Measurement precision
If PRSs are transmitted to ensure positioning precision, then UE positioning performance is improved, but conflict with PDCCH data occurs
Solution Approach 1:
The patent segments the available OFDM symbols to allocate specific symbols for PRS transmission while reserving other symbols for PDCCH. This segmentation ensures that positioning reference signals receive dedicated resources for precise UE positioning without interfering with control channel operations.
Solution Approach 2:
The patent applies local quality by assigning different roles to different OFDM symbols within the subframe. Specific symbols are optimized for positioning functions (PRS) while others are optimized for control functions (PDCCH), allowing each signal type to have optimal resource allocation without mutual interference.
3Device complexity
If CRS power is configured semi-statically, then system complexity is reduced, but UE positioning performance is limited
Solution Approach 1:
The patent introduces dynamic resource allocation for positioning reference signals, allowing the system to adaptively configure PRS transmission parameters based on positioning requirements. This dynamic approach enables enhanced UE positioning performance while maintaining semi-static CRS configuration for other functions, balancing complexity and performance.
Data Source
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AI summary
The present invention discloses methods for sending positioning reference signals (PRSs), for sending data and for receiving data. When PRSs and data carried by a physical downlink control channel (PDCCH) are required to be sent on a same physical resource, only the data carried by the PDCCH or the PRSs are sent on the same physical resource; or, when a sending end sends the PRSs and the data carried by the PDCCH on the same physical resource at the same time, a receiving end is made to ignore the received PRSs or the data carried by the PDCCH; or, the sending of the PRSs or the data carried by the PDCCH is limited so that they will not be sent on the same physical resource. The present invention also discloses devices for sending positioning reference signals, for sending data and receiving data. The present invention has solved the problem that the data carried by the PDCCH are in conflict with the PRSs over the fourth OFDM symbol when the PDCCH is sent over the first four OFDM symbols in the subframe, thereby ensuring the overall performance of the system.