NR Slot Aggregation Alignment for LTE Coexistence
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Solution Overview
Problem
Current technologies face challenges in co-channel coexistence between LTE and NR in the 5.9 GHz band, leading to potential interference and impact on the reliability of vehicle-to-everything (V2X) communications, particularly due to differences in sub-carrier spacing and resource allocation, which can affect the automatic gain control (AGC) settings in LTE receivers.
Innovation Solution
The method involves determining overlapping slots between LTE and NR, grouping NR slots to align with LTE subframes, and using the same transmit power across these slots to minimize interference, while also enabling slot aggregation and flexible transmission formats to accommodate varying latency and priority requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If NR uses different sub-carrier spacing and resource allocation than LTE, then NR can achieve higher data rates and latency performance, but it causes interference and AGC issues in LTE receivers
Solution Approach 1:
The patent segments the time domain by grouping NR slots into aggregation groups that align with LTE subframes. This segmentation allows NR to use different numerology (sub-carrier spacing) while ensuring that LTE and NR transmissions do not overlap in a way that causes AGC issues. The segmentation is achieved through the condition that the number of NR slots in an aggregation group must divide evenly into the LTE subframe structure.
Solution Approach 2:
The patent changes the parameter of transmit power by requiring that all NR slots within an aggregation group use the same transmit power level. This parameter change helps minimize interference variations that could affect LTE receiver AGC settings. The patent also implicitly changes the time domain parameter by aligning NR slot aggregations with LTE subframe boundaries.
2Reliability
If NR slots are grouped to align with LTE subframes, then co-channel coexistence is improved, but transmission flexibility and latency performance may be reduced
Solution Approach 1:
The patent introduces dynamic flexibility through the ability to configure different aggregation group sizes (e.g., 1 slot, 2 slots, 4 slots) based on traffic conditions and QoS requirements. This dynamic configuration allows the system to adapt between more rigid alignment (higher reliability) and more flexible transmission (lower latency) as needed.
Solution Approach 2:
The patent performs preliminary alignment by pre-configuring the aggregation group structure before actual transmission occurs. The gNodeB determines the aggregation group configuration in advance based on the UE's capabilities and the service requirements, allowing the UE to prepare its transmission parameters beforehand while maintaining alignment with LTE subframes.
3Object-affected harmful factors
If the same transmit power is used across all NR slots in an aggregation group, then interference is minimized, but transmission adaptability is reduced
Solution Approach 1:
The patent applies local quality by maintaining uniform transmit power within each aggregation group (local consistency) while allowing different aggregation groups to have different power levels or to be configured differently based on local conditions. This ensures that within any given aggregation group, the transmit power remains constant to avoid AGC issues, while the system as a whole retains adaptability through group-level configuration.
Data Source
AI summary
Systems, methods, apparatuses, and computer program products for handling NR slot aggregation in radio SL co-channel coexistence. A method may include determining that one or more slots of a first radio access technology overlaps a subframe of a second radio access technology. The method may also include detecting whether the second radio access technology is using the subframe of the second radio access technology. The method may further include determining by an outcome of at least one evaluated condition whether to transmit in the one or more overlapping slots or refrain to transmit in the one or more overlapping slots. The method may further include performing transmission with a same transmit power in all the slots that overlap the subframe of the second radio access technology.