Cell Grouping and TDOA Vectors for mmWave Positioning

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Solution Overview

Problem

Wireless communication systems face significant propagation loss and timing measurement inaccuracies due to beamforming at extremely high frequencies, particularly in mmW bands and MIMO systems, which affect precise positioning estimations.

Innovation Solution

A method involving grouping cells into cell groups based on shared attributes, using PRS IDs to identify membership, and deriving TDOA vectors from TOA measurements to improve positioning accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If beamforming is used to transmit RF signals in mmW bands, then signal strength and data rate are improved, but propagation loss increases and timing measurement accuracy deteriorates

Engineering Contradiction:

Improvesignal strengthVSAvoidtiming measurement accuracy

Core Design Contradiction:

PowerVSMeasurement precision

Solution Approach 1:

The patent segments the cell into multiple beam directions by configuring multiple transmission points (TPs) with different beamforming directions. Each TP transmits positioning reference signals in specific directions, allowing the UE to measure timing differences from multiple spatially separated transmission points. This segmentation enables the system to maintain beamforming's signal strength advantages while obtaining accurate timing measurements through geometric diversity, resolving the contradiction between directed signal transmission and precise timing measurement.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If multiple transmission points are configured for positioning, then positioning accuracy is improved, but device complexity increases

Engineering Contradiction:

Improvepositioning accuracyVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the transmission points serve multiple functions: they act as both communication nodes for data transmission and positioning reference signals. The same TPs used for downlink communication are configured to transmit positioning reference signals, eliminating the need for separate dedicated positioning transmitters. This multi-functionality reduces system complexity while maintaining positioning accuracy through the use of existing network infrastructure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The network entity pre-configures the transmission points with their respective beamforming directions and positioning reference signal transmission parameters before positioning operations begin. The UE receives assistance data including information about multiple TPs and their beam directions in advance, allowing it to properly configure measurements. This preliminary configuration reduces the complexity of real-time positioning calculations and enables accurate positioning using pre-established geometric relationships.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP3861364B1Simplified cell location information sharing for positioning purposes

Publication Date: 2025.10.22 QUALCOMM INC

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AI summary

Disclosed are techniques to determine a position of a user equipment (UE). In an aspect, the UE receives a plurality of positioning reference signals (PRS) from a plurality of cells. The UE determines a plurality of time of arrivals (TOA) of the plurality of PRSs, and prunes the plurality of TOAs based on the plurality of PRSs. The UE then derives a time difference of arrival (TDOA) vector from the pruned TOAs. The TDOA vector includes multiple TOA related measurements of multiple cells. The UE prunes the TOAs such that the cells represented in the TDOA vector are sufficiently geographically dispersed to determine the position of the UE at least in 2D.