Multicarrier Resource Pool Partitioning for LTE-NR V2X Coexistence
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Solution Overview
Problem
The coexistence of LTE and NR V2X communications in the same resource pool leads to AGC issues due to synchronized NR V2X transmissions causing amplifier saturation in LTE V2X devices, and the lack of flexibility in subcarrier spacing hinders optimal QoS delivery.
Innovation Solution
A method for partitioning the resource pool into time intervals and subchannels, allowing for different subcarrier spacings for data and feedback transmissions, with guard times to prevent amplifier saturation and enable coexistence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If synchronized NR V2X transmissions are used in the same resource pool as LTE V2X, then system capacity and service diversity are improved, but AGC performance deteriorates causing LTE V2X degradation
Solution Approach 1:
The resource pool is segmented into different types of time intervals: first type for LTE V2X only, second type for NR V2X only, and third type for both. This segmentation allows LTE and NR V2X to coexist while preventing AGC conflicts by ensuring that NR V2X transmissions do not occur during LTE V2X time intervals where AGC is critical.
Solution Approach 2:
The system performs preliminary configuration of time interval types and subcarrier spacing settings before actual transmissions. LTE V2X resource pools are configured with 15 kHz subcarrier spacing and appropriate time interval assignments, while NR V2X pools are configured with flexible subcarrier spacing (15, 30, or 60 kHz) and assigned to appropriate time interval types, preventing AGC issues before they occur.
2Device complexity
If a single subcarrier spacing is used in a resource pool, then implementation complexity is reduced, but service flexibility and QoS adaptability deteriorate
Solution Approach 1:
The system dynamically selects subcarrier spacing based on the type of time interval and service requirements. NR V2X time intervals can use 15 kHz, 30 kHz, or 60 kHz subcarrier spacing depending on the configured time interval type and service QoS demands, while maintaining 15 kHz for LTE V2X compatibility. This dynamic adaptation allows the system to optimize for different services without increasing overall implementation complexity.
3Speed
If NR V2X uses higher subcarrier spacings (30 kHz, 60 kHz), then transmission efficiency and latency are improved, but compatibility with LTE V2X infrastructure deteriorates
Solution Approach 1:
Different subcarrier spacings are applied locally to different time interval types and resource pools. LTE V2X resource pools maintain 15 kHz subcarrier spacing for full LTE compatibility, while NR V2X resource pools can use 30 kHz or 60 kHz for improved transmission efficiency. The system applies the appropriate subcarrier spacing locally based on the specific time interval type and service requirements, ensuring both compatibility and performance.
Data Source
AI summary
The invention relates to a method implemented in a device-to-device communication system for a transmission and/or a reception of multicarrier radio signals, using a resource pool, the resource pool being partitioned, in the time domain, in dine intervals, each time interval comprising multicarrier symbols with respect to a first subcarrier spacing, at least a part of the multicarrier symbols being available for data transmission in each time interval, the resource pool being partitioned, in the frequency domain, in L1 subchannels with respect to the first subcarrier spacing, the resource pool comprising sets of N1*L1 time-frequency units, each set spanning over N1 time intervals and over L1 subchannels with respect to the first subcarrier spacing, each set being associated to a feedback occasion comprised, in the time domain, within multicarrier symbols with respect to the first subcarrier spacing not available for data transmission with respect to the first subcarrier spacing.