Licensed-Assisted Sidelink Access for Synchronized FBE Carriers
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Solution Overview
Problem
Sidelink communication in licensed spectrum faces bandwidth limitations, particularly in vertical domains like Intelligent Transportation Systems, necessitating offloading to unlicensed spectrum, but existing methods for scheduling access to unlicensed spectrum are less efficient and unstable, especially for Frame-Based Equipment (FBE) access.
Innovation Solution
A heterogeneous carrier aggregation design is implemented, offloading sidelink traffic from a licensed band primary carrier to an unlicensed band secondary carrier, using timing from the licensed band for synchronized FBE access, which coordinates sidelink communication across both bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If sidelink traffic is offloaded from licensed band to unlicensed band, then bandwidth capacity increases, but access stability and efficiency deteriorate
Solution Approach 1:
The patent uses licensed band sidelink control channel as an intermediary to assist unlicensed band channel access. The device performs clear channel assessment (CCA) on unlicensed band by listening to sidelink control information transmitted on licensed band, which mediates between the licensed band's stability and unlicensed band's bandwidth capacity, enabling stable and efficient access to both bands simultaneously
2Productivity
If FBE-based access is used in unlicensed band, then channel access efficiency improves, but access stability deteriorates due to lack of timing synchronization
Solution Approach 1:
The patent synchronizes FBE frame timing in unlicensed band with the licensed band's frame structure, creating equipotential timing conditions across both bands. By aligning frame boundaries and using the same frame timing reference, the system eliminates timing drift and instability while maintaining the high efficiency of FBE-based access in unlicensed band
3Productivity
If all sidelink communication is handled on licensed band, then access control efficiency is high, but bandwidth capacity is insufficient
Solution Approach 1:
The patent segments sidelink communication functions by band: licensed band handles control signaling and high-priority traffic requiring efficient access control, while unlicensed band handles bulk data traffic requiring large bandwidth capacity. This segmentation allows each band to operate optimally for its designated function, achieving both high access control efficiency and sufficient bandwidth capacity
Data Source
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AI summary
Aspects of the disclosure relate to, at a wireless communication device, occupying a slot in a first subchannel, wherein the first subchannel comprises a sidelink subchannel in a licensed band, transmitting sidelink control in the first subchannel during the slot, except during a symbol gap indicated to include at least a last symbol of a plurality of symbols supported by the slot, seeking access to a secondary carrier in an unlicensed band, and transmitting sidelink traffic in the secondary carrier upon receiving the access to the secondary carrier. Other aspects, embodiments, and features are also claimed and described.