Scheduling Request Preemption in Uplink Shared Channel
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Solution Overview
Problem
In wireless communication networks, particularly in the New Radio (NR) standard, there is a challenge in handling scheduling requests (SRs) for uplink transmissions with low latency requirements during ongoing slot-based PUSCH transmissions, as resource collisions can lead to information loss and transmission failures.
Innovation Solution
The user equipment (UE) determines whether to preempt an ongoing PUSCH transmission based on SR periodicity and priority, sending the SR within acceptable delay if periodicity is below a certain threshold or preempting if above, with higher-layer signaling configuring preemption permissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the UE preempts the ongoing PUSCH transmission to send the SR immediately, then the latency for low latency data is reduced, but the data integrity of the ongoing PUSCH transmission is compromised
Solution Approach 1:
The system dynamically adjusts the SR transmission behavior based on the SR periodicity parameter. When SR periodicity is below the threshold, the UE waits for the next SR occasion to maintain PUSCH integrity. When SR periodicity exceeds the threshold, the UE preempts PUSCH transmission to send SR immediately, thus adapting the transmission strategy to the specific service requirements
Solution Approach 2:
The invention uses the SR periodicity parameter as a decision criterion. By comparing the SR periodicity against a threshold, the system determines whether to preempt PUSCH or wait for the next SR occasion, thereby changing the transmission behavior based on parameter values
2Reliability
If the UE waits for the next SR occasion to send the SR, then the PUSCH transmission continuity is maintained, but the latency for low latency data increases
Solution Approach 1:
The system dynamically selects between two transmission strategies: waiting for the next SR occasion (when periodicity is acceptable) or preempting PUSCH (when periodicity is too long), based on real-time evaluation of the SR periodicity parameter
Solution Approach 2:
The decision to wait or preempt is determined by the SR periodicity parameter value. When the periodicity is within acceptable limits, the system maintains PUSCH continuity by waiting. When periodicity exceeds the threshold, the system changes behavior to preempt and send SR immediately
3Loss of time
If the UE preempts PUSCH for SR transmission, then the SR is sent within acceptable delay, but information in one or both channels is lost
Solution Approach 1:
The system performs a preliminary check of the SR periodicity parameter before deciding to preempt PUSCH. This preliminary evaluation prevents unnecessary preemption and potential information loss by determining in advance whether the current SR timing requirements justify interrupting PUSCH transmission
Data Source
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AI summary
Methods and apparatus are provided for fast transmission by a UE of scheduling requests for low latency data transmission. When transmit data for transmission on an uplink shared channel arrives, the UE determines whether the scheduling request to be sent by the user equipment to request uplink resources for transmission of the data will overlap a scheduled data transmission. If it is determined that the scheduling request will overlap the scheduled data transmission, the UE may preempt the scheduled data transmission to transmit the scheduling request. Preemption may be based on one or more predetermined criteria including the priority of the new transmit data, the periodicity of the scheduling request interval, and the remaining duration of the ongoing data transmission.