D2D Positioning Synchronization via Resource Subsets
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Solution Overview
Problem
Current wireless communication systems, particularly in LTE networks, face challenges in device-to-device (D2D) positioning due to bandwidth limitations, timing offsets, and power consumption, which affect the accuracy of time of arrival (TOA) and time difference of arrival (TDOA) measurements, especially for UEs without GPS or in indoor environments.
Innovation Solution
A method where user equipment (UE) adjusts transmission timing based on received sequences from reference UEs to synchronize and determine its position using D2D signaling, allowing for accurate TOA/TDOA calculations even in RRC_IDLE mode, by transmitting and receiving positioning messages across specific subsets of resources identified by resource IDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If UEs transmit positioning signals continuously to improve positioning accuracy, then measurement precision improves, but power consumption increases
Solution Approach 1:
The patent implements periodic positioning signal transmission where reference UEs transmit positioning signals at specific time intervals rather than continuously. The network configures periodic windows for signal transmission and reception, allowing UEs to enter low-power states between transmission windows while maintaining positioning accuracy through scheduled measurements.
Solution Approach 2:
Reference UEs autonomously select and transmit positioning signals without requiring continuous network coordination. The system enables UEs to self-organize positioning measurements during configured time windows, reducing the need for continuous active communication with the network and thereby reducing power consumption while maintaining measurement precision.
2Measurement precision
If UEs transmit positioning signals at high power to improve signal detection, then measurement precision improves, but energy consumption increases
Solution Approach 1:
The patent employs periodic transmission windows where UEs transmit positioning signals at configured intervals rather than continuously. During these periodic windows, signals are transmitted at optimized power levels, while between windows UEs can reduce power consumption by entering idle or low-power states, thus achieving signal detection accuracy without sustained high power consumption.
3Measurement precision
If the network configures frequent positioning measurements to improve accuracy, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent divides the positioning measurement process into distinct time windows and resource subsets. Different resource subsets are allocated for different measurement phases, and reference UEs are assigned specific time windows for signal transmission. This segmentation simplifies the synchronization complexity by providing clear, structured time-frequency resources for each measurement task.
Solution Approach 2:
The network pre-configures positioning resource subsets, time windows, and synchronization parameters before positioning measurements begin. Reference UEs receive advance configuration information about when and how to transmit positioning signals, allowing them to prepare and execute measurements efficiently without complex real-time decision-making, thereby reducing device complexity while maintaining high measurement precision.
Data Source
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AI summary
A method, an apparatus, and a computer program product for wireless communication are provided. The apparatus may be a UE. The apparatus may transmit a message in a first subset of a set of resources. The message may include a position of the apparatus and a resource ID indicating at least one symbol in a second subset of the set of resources for transmitting a sequence. The apparatus may transmit the sequence in the at least one symbol in the second subset of the set of resources identified by the resource ID, receive at least one other sequence, adjust a transmission timing based on the received at least one other sequence, and transmit, based on the adjusted transmission timing, the sequence in one or more symbols in a third subset of the set of resources.