OFDM Scheduling Unit Alignment for LTE-NR Coexistence
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Solution Overview
Problem
In the evolution of LTE to NR, the alignment of scheduling units with different subcarrier spacings and cycle prefixes leads to resource waste and inefficiencies, particularly in supporting both LTE short transmission time intervals and NR URLLC services on the same carrier.
Innovation Solution
The scheduling unit is formed by aligning eight OFDM symbols with a subcarrier spacing of 60 kHz and normal CPs with seven OFDM symbols having a subcarrier spacing of 60 kHz and new extended CPs, allowing for boundary alignment with two LTE OFDM symbols, thereby reducing resource waste and enabling simultaneous support of LTE and NR URLLC services.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the scheduling unit uses seven OFDM symbols with 60 kHz SCS and normal CPs, then the URLLC service can be supported, but the boundary alignment with LTE OFDM symbols is lost causing resource waste
Solution Approach 1:
The scheduling unit is segmented into multiple configurations (7 symbols with normal CP, 7 symbols with extended CP, 8 symbols with normal CP) to enable flexible alignment with LTE boundaries while maintaining URLLC service support
Solution Approach 2:
The cycle prefix length parameter is changed from normal CP to extended CP in certain configurations, allowing the scheduling unit boundary to align with LTE OFDM symbol boundaries while maintaining the required time length for URLLC services
2Length of stationary object
If the scheduling unit uses six OFDM symbols with 60 kHz SCS and extended CPs, then coverage range can be expanded, but the boundary alignment with LTE OFDM symbols is lost causing time waste
Solution Approach 1:
The scheduling unit configuration is segmented to include 6 symbols with extended CP as one of the valid options, enabling coverage expansion while providing alternative configurations (7 or 8 symbols) that align with LTE boundaries to avoid time waste
Solution Approach 2:
The system dynamically selects between different scheduling unit configurations (6, 7, or 8 symbols with different CP types) based on the specific service requirements and alignment needs, making the system adaptable to both coverage expansion and boundary alignment scenarios
3Adaptability or versatility
If different CP lengths are supported for 60 kHz SCS, then both LTE evolution and NR URLLC can coexist, but the scheduling unit boundary alignment becomes complex
Solution Approach 1:
Different parts of the scheduling unit configuration space are assigned different CP lengths (normal or extended) based on local requirements, allowing LTE and NR URLLC to coexist while maintaining manageable alignment complexity through standardized time lengths
Solution Approach 2:
The scheduling unit is designed with multi-functionality to support both LTE evolution and NR URLLC services by accommodating different CP lengths and symbol counts while maintaining universal time length alignment with LTE boundaries
Data Source
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AI summary
A data transmission method comprises: a sending end sends data to a reception end on one or more OFDM symbols in a modulation unit, the time length of the modulation unit being the time length of two 15kHz LTE OFDM symbols having normal cyclic prefixes, the modulation unit being formed by seven or eight OFDM symbols having a subcarrier interval of 60kHz, or the modulation unit being formed by seven OFDM symbols having a subcarrier interval of 60kHz as well as a first gap, or the modulation unit being formed by eight OFDM symbols having a subcarrier interval of 60kHz as well as a second gap, the OFDM symbols having a subcarrier interval of 60kHz comprising cyclic prefixes and valid data, and in the modulation unit, two types of different cyclic prefix lengths being used on the seven OFDM symbols having a subcarrier interval of 60kHz and the eight OFDM symbols having a subcarrier interval of 60kHz.