PRS Sequence Generation and Positioning in LTE
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Solution Overview
Problem
Current methods for transmitting position reference signals (PRS) in LTE systems face challenges in ensuring effective sequence acquisition, leading to limited UE positioning performance due to semi-static configuration and interference from neighboring cells.
Innovation Solution
A method for generating and transmitting a PRS sequence with a length of 2 × NRB PRS, where NRB PRS is configured by high-layer signaling, determining its position in a physical resource block, and transmitting it at that position, ensuring effective sequence acquisition and reduced interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the PRS sequence is generated with fixed length 2×NRBmax,DL and then truncated to match actual bandwidth, then the positioning function can be realized in any circumstance, but the sequence generation complexity increases
Solution Approach 1:
The patent generates a PRS sequence with maximum length 2×NRBmax,DL in advance, before knowing the actual bandwidth requirement. This preliminary generation ensures that sufficient sequence data is available regardless of the actual bandwidth configuration, and the sequence is then truncated to match the actual bandwidth NRBPRS. This approach guarantees positioning function realization in any circumstance while managing complexity through a standardized generation process.
2Adaptability or versatility
If the initial frequency domain position vshift of PRS is generated randomly, then the PRS transmission flexibility is improved, but the interference from neighboring cells cannot be effectively reduced
Solution Approach 1:
The patent applies different initialization approaches for different scenarios: for intra-cell positioning, a fixed initialization method is used, while for inter-cell positioning, the initialization incorporates cell-specific parameters. This local differentiation allows the system to maintain flexibility where needed while reducing interference through cell-specific patterns where appropriate, rather than using a single random initialization for all cases.
3Measurement precision
If the PRS transmitting cycle is set to 160ms, 320ms, 640ms or 1280ms with 1, 2, 4 or 6 contiguous subframes, then the positioning precision is improved, but the signaling overhead and system complexity increase
Solution Approach 1:
The patent introduces dynamic PRS configuration where the transmitting cycle and number of contiguous subframes can be adjusted based on actual positioning requirements. The system supports multiple configurations (160ms/320ms/640ms/1280ms with 1/2/4/6 subframes) that can be selected dynamically, allowing the network to optimize between positioning precision and system complexity based on current needs, rather than being fixed to a single configuration.
Data Source
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AI summary
The present disclosure provides a method and system for transmitting a position reference signal, which includes: acquiring a currently needed Position Reference Signal (PRS) sequence with a length of 2×NRBPRS wherein NRBPRS is the PRS bandwidth configured by high layer signaling, which is represented by a unit of a resource block; determining the position of the PRS sequence in a physical resource block; and transmitting the acquired PRS sequence on the determined position. With the method of the present disclosure, a currently needed PRS sequence is acquired directly, or at first, a PRS sequence with the maximum length is generated, and then the currently needed PRS sequence is intercepted from the PRS sequence with the maximum length. The present disclosure ensures that an effective PRS sequence can be acquired in any circumstance, thereby ensuring the realization of the positioning function of the PRS.