PRS Port Muting for Multi-Antenna Positioning Accuracy
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Solution Overview
Problem
Current wireless communication networks face challenges in positioning measurements, particularly with Observed Time Difference of Arrival (OTDOA) methods, due to ambiguity issues when multiple antenna ports are used, leading to reduced measurement quality and interference in urban environments.
Innovation Solution
The solution involves using a mix of reference signal types, such as CRS and PRS, where CRS is transmitted from multiple antenna ports for channel estimation and PRS is transmitted from a single port for positioning measurements, with dynamic port configuration and muting patterns to avoid ambiguity and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PRS is transmitted from multiple antenna ports simultaneously, then channel diversity and coverage are improved, but positioning measurement ambiguity increases and measurement quality deteriorates
Solution Approach 1:
The patent segments the positioning reference signal transmission by antenna port, where each antenna port transmits PRS with a unique orthogonal cover code (OCC). This segmentation allows the UE to distinguish and measure PRS from different antenna ports separately, avoiding measurement ambiguity while maintaining the benefits of multi-antenna transmission for coverage and diversity.
Solution Approach 2:
The patent introduces a new dimension for PRS differentiation by applying orthogonal cover codes in the code domain. Instead of relying solely on time-frequency resources, the invention adds code orthogonality as an additional dimension, enabling simultaneous transmission from multiple antenna ports without interference or ambiguity.
2Measurement precision
If PRS transmission is restricted to single antenna port, then positioning measurement ambiguity is avoided, but channel estimation capability and signal coverage are reduced
Solution Approach 1:
The patent segments the PRS transmission function into two parts: Cell ID-based PRS for positioning measurements (transmitted from a single antenna port to avoid ambiguity) and antenna-specific reference signals for channel estimation (transmitted from multiple antenna ports). This segmentation allows each function to be optimized independently, maintaining measurement precision while preserving coverage capability.
Solution Approach 2:
The patent makes the reference signal system multi-functional by designing it to serve both positioning measurement and channel estimation purposes. Through configurable transmission modes and orthogonal cover codes, the same PRS infrastructure can adapt to different functional requirements, providing universal coverage while maintaining measurement accuracy.
3Measurement precision
If CRS is transmitted from multiple antenna ports for channel estimation, then channel estimation accuracy is improved, but interference with positioning measurements increases in urban environments
Solution Approach 1:
The patent extracts the channel estimation function from the positioning reference signal transmission and assigns it to antenna-specific reference signals (CRS) transmitted on dedicated resources. This separation allows PRS to focus solely on positioning measurements with minimized interference, while CRS handles channel estimation independently, reducing mutual interference in urban environments.
Solution Approach 2:
The patent introduces antenna-specific reference signals as an intermediary between the multi-antenna transmission system and the positioning measurement process. These intermediary signals provide the necessary channel estimation capability without directly interfering with the PRS positioning measurements, acting as a mediator that enables both functions to coexist with reduced interference.
Data Source
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AI summary
This document discloses a method of reference signal transmissions by a wireless communication, network base station in a wireless communication network, wherein said method is characterized by the steps of: transmitting, in a cell associated with said wireless communication network base station, cell-specific reference signals, CRSs, from any one or more of antenna ports in a plurality of antenna ports used for transmitting in said cell; transmitting, in said cell, positioning reference signals, PRSs, from only one of said antenna ports at a time according to a port configuration that determines which one of the antenna ports is selected for use in transmitting the PRSs at any given one of the transmission occasions that are defined for transmission of the PRSs, wherein said CRSs are transmitted to aid channel estimation while said PRSs are transmitted in defined positioning sub-frames explicitly for positioning-related measurements; receiving signaling indicating a PRS muting configuration to use for selecting individual ones of said antenna ports for transmitting said PRSs over said one or more transmission occasions, wherein said muting configuration is a function of the cell ID of the cell associated with the wireless base station, one or more antenna ports of the base station used for transmitting CRSs, and the antenna port to be used for transmitting the PRS; dynamically changing which one of said antenna ports in said cell is selected for use in transmitting the PRSs over one or more of said transmission occasions; and controlling transmission of the CRSs in said cell so as not to coincide with symbol times in any of said transmission occasions that are used for transmitting symbols comprising the PRSs.