D2D Positioning Using Zadoff-Chu Sequences
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Solution Overview
Problem
Current wireless communication systems, particularly in LTE, face challenges in accurately determining the position of user equipment (UE) without GPS or in indoor environments, due to inaccurate base station signaling and limited bandwidth, which affects the precision of time of arrival (TOA) or time difference of arrival (TDOA) measurements.
Innovation Solution
A device-to-device (D2D) positioning method using a distributed MAC protocol, where UEs broadcast Zadoff Chu sequences with specific resource IDs, allowing other UEs to determine their position based on timing information and known positions of reference UEs, even in RRC_IDLE mode, to improve positioning accuracy and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If base station signaling is used for positioning, then positioning coverage is provided, but positioning accuracy deteriorates due to inaccurate signaling and limited bandwidth
Solution Approach 1:
The patent introduces user equipment (UE) as intermediary devices that relay positioning information between the base station and other UEs. Reference UEs broadcast their known positions and timing information, acting as intermediaries that enable more accurate positioning measurements without requiring direct base station signaling to each UE, thereby resolving the accuracy limitation of base station signaling.
Solution Approach 2:
The patent enables UEs to autonomously determine their positions by receiving and processing timing information from reference UEs without requiring continuous base station intervention. The positioning function serves itself through distributed UE participation, where each UE can act as a reference for others, eliminating the need for accurate base station signaling to every device.
2Measurement precision
If GPS is used for positioning, then positioning accuracy is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent creates a virtual positioning system using distributed UEs that replicate the functionality of GPS without requiring actual GPS hardware. Instead of relying on satellite signals, the system copies the positioning function by having UEs broadcast their positions and timing information, allowing other UEs to calculate their locations based on these broadcasts, thereby achieving GPS-like accuracy without GPS complexity.
Solution Approach 2:
The patent replaces the mechanical/GPS-based positioning system with a communication-based positioning system. Instead of using GPS receivers and satellite signals, the system uses D2D communication signals and timing measurements between UEs to determine positions, substituting a complex hardware-dependent system with a simpler software-based communication solution.
3Measurement precision
If continuous positioning monitoring is performed, then positioning accuracy is maintained, but power consumption increases
Solution Approach 1:
The patent implements periodic positioning updates instead of continuous monitoring. UEs perform positioning measurements at specific intervals by listening to reference UE broadcasts at predetermined times, maintaining positioning accuracy while allowing the device to enter low-power states between measurement periods, thereby significantly reducing overall power consumption compared to continuous monitoring.
Data Source
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AI summary
A method, an apparatus, and a computer program product for wireless communication are provided. The apparatus determines a position of the apparatus. The apparatus broadcasts information in a first subset of a set of resources. The information includes the position of the apparatus, a sequence ID, and a resource ID associated with a second subset of the set of resources. The apparatus broadcasts a sequence in at least one symbol of the second subset of the set of resources. The at least one symbol is identified by the resource ID and the sequence is identified by the sequence ID.