Decoupled Mini-Slot SCI for Sidelink Collision Avoidance
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Solution Overview
Problem
In wireless communication systems, particularly in 5G NR and sidelink communications, the increasing demand for vehicle-to-everything (V2X) technology leads to crowded networks, increasing the likelihood of allocation collisions, which can prevent successful decoding of UE transmissions and fail to meet latency specifications due to half-duplex limitations.
Innovation Solution
A method and apparatus for wireless communication that involves selecting a resource from a dedicated physical sidelink control channel (PSCCH) resource pool with a mini-slot structure and transmitting a decoupled mini-slot first stage sidelink control information (SCI-1) message, which schedules the physical sidelink shared channel (PSSCH) in a legacy resource pool, using a time division multiplexed approach to prevent collisions and ensure resource reservations are heard by half-duplex transmitters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated PSCCH resource pool with mini-slot structure is introduced for SCI-1 transmission, then the reliability of resource reservation and reduction of collisions are improved, but the device complexity increases
Solution Approach 1:
The control channel is segmented into two independent parts: a dedicated PSCCH resource pool for SCI-1 transmission and a legacy resource pool for PSSCH data transmission. This segmentation allows SCI-1 to be transmitted with higher reliability through mini-slot structure while maintaining backward compatibility with existing LTE resource pools, thus resolving the contradiction between improved reliability and increased complexity.
Solution Approach 2:
The patent introduces a new time-domain dimension by using mini-slots (2-7 symbols) instead of traditional slots (14 symbols) for SCI-1 transmission. This dimensional change enables faster transmission of control information, reducing latency and improving reliability without requiring a complete redesign of the control channel structure.
2Loss of time
If mini-slot structure is used for SCI-1 transmission, then the latency is reduced and collision chance is minimized, but the resource allocation flexibility is reduced
Solution Approach 1:
The system dynamically configures the number of mini-slots (2-7 symbols) based on the specific transmission requirements and channel conditions. This dynamic adjustment allows the system to optimize between latency reduction and resource allocation flexibility, resolving the contradiction by making the mini-slot duration adaptable rather than fixed.
Solution Approach 2:
The control information transmission is segmented into two stages: SCI-1 transmitted via mini-slots in the dedicated PSCCH pool for low-latency scheduling, and SCI-2 transmitted via PSSCH for additional control details. This segmentation allows the mini-slot structure to provide low latency for critical scheduling information while maintaining flexibility through the two-stage transmission process.
3Device complexity
If half-duplex transmitters are used in sidelink communications, then the device simplicity is maintained, but the collision probability increases and reliability decreases
Solution Approach 1:
The system performs preliminary resource reservation by transmitting SCI-1 messages in advance through the dedicated PSCCH resource pool before the actual data transmission. This preliminary action allows half-duplex transmitters to know future resource allocations ahead of time, enabling them to avoid collisions without requiring complex simultaneous transmission and reception capabilities.
Solution Approach 2:
The dedicated PSCCH resource pool acts as an intermediary channel that independently from the data channel, providing advance notification of resource reservations. This intermediary mechanism allows half-duplex devices to receive scheduling information without needing to transmit and receive simultaneously, thus maintaining device simplicity while improving communication reliability.
Data Source
AI summary
A method of wireless communication, by a user equipment (UE), includes selecting a resource from a dedicated physical sidelink control channel (PSCCH) resource pool that has multiple potential PSCCH time domain resources with a mini-slot structure. The method also includes transmitting a mini-slot first stage sidelink control information (SCI-1) message on the selected resource. The mini-slot SCI-1 message is decoupled from a physical sidelink shared channel (PSSCH) associated with a data resource pool.