Wireless Device Scheduling Request for Unlicensed Spectrum Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In 5G NR wireless communication, achieving high reliability and low latency in unlicensed spectrum is challenging due to the non-guaranteed nature of unlicensed carriers, which complicates the efficient coexistence with other use cases like eMBB and URLLC, especially when deterministic communication requirements are not met.
Innovation Solution
A wireless device initiates a procedure to determine channel occupancy in unlicensed spectrum using Listen Before Talk (LBT) or Clear Channel Assessment (CCA) and simultaneously transmits a scheduling request on licensed spectrum, allowing data transmission to proceed on unlicensed spectrum if available, while ensuring reliability and latency targets are met by complementing unlicensed with licensed spectrum usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a device performs Listen Before Talk (LBT) or Clear Channel Assessment (CCA) to determine channel occupancy in unlicensed spectrum, then the device can transmit data using unlicensed spectrum, but the transmission reliability and latency cannot be guaranteed due to the non-guaranteed nature of unlicensed carriers
Solution Approach 1:
The patent segments the transmission path into two parts: unlicensed spectrum for initial data transmission (when channel is free) and licensed spectrum as backup. The device performs LBT/CCA on unlicensed channel, and if successful, transmits data there; otherwise, it falls back to licensed spectrum, thus achieving both high productivity when possible and reliable fallback when needed.
Solution Approach 2:
The patent sends a scheduling request on the licensed carrier before attempting transmission on the unlicensed carrier. This preliminary action reserves resources on the licensed carrier as a backup, ensuring that if the unlicensed transmission fails, the device can immediately use the pre-resourced licensed carrier without additional latency.
2Adaptability or versatility
If a device uses unlicensed spectrum for data transmission, then spectrum utilization is improved, but the coexistence with other use cases like eMBB and URLLC becomes complicated
Solution Approach 1:
The licensed carrier acts as an intermediary and coordinator. The device first sends a scheduling request on the licensed carrier, which serves as a mediator to inform the network about the intended unlicensed transmission. This intermediary mechanism simplifies coexistence management by providing a controlled interface between unlicensed and licensed spectrum operations.
Solution Approach 2:
The patent implements dynamic spectrum selection where the device can switch between unlicensed and licensed carriers based on channel conditions. The device performs LBT/CCA dynamically and adjusts its transmission path in real-time, allowing flexible adaptation to spectrum availability while maintaining simple coexistence through licensed carrier coordination.
3Reliability
If a device transmits a scheduling request before completing LBT/CCA procedure, then the device ensures reliability targets are met by having licensed spectrum as backup, but the device complexity increases
Solution Approach 1:
The device performs the scheduling request transmission as a preliminary action before completing the LBT/CCA procedure. This ensures that resources are reserved on the licensed carrier in advance, providing a guaranteed backup path that meets reliability and latency targets without adding complex post-transmission fallback procedures.
Data Source
AI summary
Methods and apparatus are provided. In an example aspect, a method performed by a wireless device is provided. The method includes initiating a procedure to determine whether a channel in unlicensed spectrum for transmission of data to a base station using unlicensed spectrum is occupied, and before completion of the procedure, transmitting a scheduling request to the base station, the scheduling request for transmission of the data to the base station using licensed spectrum.