Two-Stage Uplink Scheduling Verification in Unlicensed Cells
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Solution Overview
Problem
The existing two-stage uplink scheduling procedure in LTE systems for unlicensed cells is prone to false detection of trigger A messages, leading to unintended uplink transmissions, which cause intracell and intercell interference and affect coexistence with other unlicensed technologies like Wi-Fi.
Innovation Solution
Incorporating additional verification data fields in the trigger A message, such as the CSI request, SRS request, and TPC command fields, to allow user equipment (UE) to verify the message's validity, reducing the risk of false detection by setting specific bits to predetermined values, and ensuring that only valid trigger A messages trigger uplink transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the two-stage uplink scheduling procedure is implemented in unlicensed cells, then uplink resource allocation flexibility is improved, but false detection of trigger A messages occurs leading to unintended uplink transmissions
Solution Approach 1:
The patent applies preliminary action by introducing verification data fields (such as CSI request, SRS request, and TPC command fields) into the trigger A message before transmission. These fields contain predetermined values that serve as validation markers, allowing the UE to verify message authenticity in advance before executing uplink transmissions, thereby preventing false detections while maintaining scheduling flexibility.
2Reliability
If verification data fields are added to trigger A messages, then false detection rate is reduced, but message structure complexity increases
Solution Approach 1:
The patent employs universality by using existing data fields in the trigger A message (CSI request, SRS request, TPC command fields) for dual purposes: their original functions plus serving as verification carriers with predetermined values. This multi-functionality approach adds verification capability without requiring entirely new message structures, thus reducing the increase in complexity while improving detection accuracy.
3Object-affected harmful factors
If unintended uplink transmissions are prevented through verification, then interference with other unlicensed technologies is reduced, but scheduling procedure overhead increases
Solution Approach 1:
The patent extracts the verification function from the main scheduling procedure by utilizing specific data fields within the existing trigger A message structure. Rather than adding a separate verification message or procedure, the verification capability is extracted and embedded within the already-transmitted trigger A message, thereby preventing interference while minimizing additional overhead.
Data Source
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AI summary
The invention relates to a user equipment (UE) scheduled with uplink radio resources. At least one unlicensed cell is configured for communication between the UE and a base station(BS). The UE receives from the BS a first-stage uplink scheduling message. The UE determines whether the first-stage uplink scheduling message is valid, which comprises determining that it is valid in case one or more bits of one or more data fields in the first-stage uplink scheduling message are set to respectively predetermined values. The UE receives from the BS a second- stage uplink scheduling message related to the first-stage uplink scheduling message. The UE determines, when receiving the second-stage uplink scheduling message, that an uplink transmission is scheduled in case it determined that the first-stage uplink scheduling message is valid. The UE then performs, in case it determined that an uplink transmission is scheduled, an uplink transmission via the unlicensed cell.