Beamformed Positioning RSTD Configuration for 5G Accuracy
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Solution Overview
Problem
Wireless communication networks, particularly those using beamformed communication, face challenges in positioning due to severe propagation loss at high frequencies and multipath propagation, which affects the accuracy of timing measurements and signal strength, especially in 5G networks operating at millimeter wave frequencies.
Innovation Solution
The proposed solution involves configuring the range and granularity for measuring and reporting reference signal timing differences (RSTD) based on beam parameters such as repetition factor, beam shape, frequency band, and cyclic prefix, and transmitting parameters like angle of departure and beamwidth to enhance positioning accuracy, allowing for more precise determination of a mobile device's position and increasing the number of visible neighbor cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If beamforming is used to extend RF signal coverage at mmW frequencies, then signal propagation loss is reduced, but positioning accuracy deteriorates due to multipath propagation and beam directionality
Solution Approach 1:
The patent segments the positioning measurement process by identifying and separately handling different propagation paths (direct path vs. reflected paths). The mobile device measures RSTD for multiple beams and identifies the direct path beam by comparing timing and signal characteristics, thereby isolating the accurate positioning measurement from multipath interference.
Solution Approach 2:
The patent employs dynamic beam sweeping where the base station transmits reference signals through multiple beams in different directions sequentially. The mobile device dynamically switches between receiving different beams and measures RSTD for each beam, allowing the system to adapt to changing propagation conditions and identify the direct path beam among multiple reflected paths.
2Device complexity
If traditional timing measurement methods are used in beamformed networks, then implementation complexity is low, but positioning accuracy deteriorates due to inability to account for beam-specific parameters
Solution Approach 1:
The patent applies preliminary action by having the base station pre-transmit beam-specific parameters (beam index, angle of departure, beamwidth) along with reference signals. The mobile device uses these pre-provided parameters to correctly associate measured RSTD values with specific beam directions and characteristics, enabling accurate positioning without complex real-time analysis.
Solution Approach 2:
The patent implements feedback mechanisms where the mobile device measures RSTD for multiple beams and reports measurements along with beam identifiers to the base station. The base station uses this feedback to determine the direct path beam by comparing measurements from different beams, leveraging the known beam geometry and propagation characteristics to resolve positioning ambiguity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves positioning accuracy by optimizing beamforming techniques, reducing propagation loss, and enhancing the ability to detect changes in position and orientation, thereby supporting more reliable and precise location determination in wireless networks.
Implementation Method 1
transmitters may use beamforming to extend RF signal coverage. In particular, transmit beamforming is a technique for emitting an RF signal in a specific direction
Implementation Method 2
a transmitter may use an array of antennas (also referred to as a 'phased array' or an 'antenna array') that creates a beam of RF waves that can be 'steered' to point in different directions, without actually moving the antennas. Specifically, the RF current is fed to the individual antennas with the correct phase relationship so that the radio waves from the separate antennas add together to increase the radiation in a desired direction, while cancelling the radio waves from the separate antennas to suppress radiation in undesired directions.
Data Source
AI summary
Positioning methods suitable for use in a wireless network that utilizes beamformed communication are disclosed. In an aspect, a range and/or granularity for reporting a reference signal timing difference (RSTD) may be configurable according to one or more beam parameters (e.g., a repetition factor, a beam shape, a frequency band, a subcarrier spacing numerology, a cyclic prefix, etc.). In another aspect, a transmitting node may transmit one or more parameters associated with a beam used to transmit a positioning reference signal (e.g., an angle of departure, a zenith of departure, a beamwidth, etc.). According to another aspect, a cyclic prefix length for a positioning reference signal that a transmitting node transmits via one or more beams may be configured to increase a number of neighbor cells visible to a receiving node.