Sidelink Proximity Discovery via PSFCH Resource Reuse
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Solution Overview
Problem
Current wireless communication systems, particularly in new radio (NR) technology, face challenges in efficiently determining proximity between sidelink user equipments (UEs) for sidelink channel access, leading to potential listen before talk (LBT) blocking in unlicensed bands, which affects spectral efficiency.
Innovation Solution
The implementation of a proximity discovery technique that involves receiving an indication of a proximity discovery resource in a physical sidelink feedback channel (PSFCH) symbol, transmitting a proximity discovery request, and receiving a bit map sequence from other UEs to generate a sidelink jamming graph, enabling the base station to schedule UEs and avoid LBT blocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional sidelink channel access methods are used, then UEs can communicate in unlicensed bands, but LBT blocking occurs which reduces spectral efficiency
Solution Approach 1:
The system performs preliminary proximity discovery by transmitting discovery requests and receiving responses before actual data transmission. This advance preparation identifies which UEs are within proximity and likely to cause LBT blocking, allowing the base station to schedule transmissions that avoid conflicts and improve both channel access reliability and spectral efficiency
2Measurement precision
If proximity discovery is performed using existing methods, then UE proximity can be determined, but signaling overhead increases and discovery is not prompt enough
Solution Approach 1:
The proximity discovery function is merged with the existing PSFCH (Physical Sidelink Feedback Channel) resources already allocated for sidelink communication. By reusing these dedicated feedback resources for dual purposes (both feedback and proximity discovery), the system eliminates the need for separate discovery signaling, reducing overhead and enabling prompt discovery without time loss
3Measurement precision
If more discovery resources are allocated, then proximity determination becomes more accurate, but signaling overhead increases
Solution Approach 1:
The PSFCH resources are designed to serve multiple functions simultaneously: they carry both the proximity discovery responses from UEs and the normal feedback information for sidelink communications. This multi-functionality ensures that no additional dedicated discovery resources are needed, maintaining high discovery accuracy while avoiding increased signaling overhead and system complexity
Data Source
AI summary
Certain aspects of the present disclosure provide a user equipment (UE) that may receive an indication of a proximity discovery resource in a physical sidelink feedback channel (PSFCH) symbol from a network entity. The UE may transmit a proximity discovery request including the indication of the proximity discovery resource. The UE may receive a PSFCH sequence associated with the proximity discovery resource from other UEs that may respond to the proximity discovery request. The UE may transmit a bit map sequence indicative of the other UEs to the network entity. The network entity may determine a proximity between the UE and the other UEs based on the bit map sequence. The network entity may schedule the UE and the other UEs based on the proximity.