Uplink Control Channel Collision Avoidance for Wireless Scheduling
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Solution Overview
Problem
In wireless communication systems, collisions between scheduling requests (SRs) and uplink control information (UCI) on different channels can reduce throughput and cause ambiguity in resource selection for user equipment (UE), especially when simultaneous transmission on multiple channels is not possible.
Innovation Solution
The UE identifies collisions between SRs and HARQ feedback and consolidates transmissions on the short physical uplink control channel (sPUCCH), determining resources based on the number of HARQ bits, coding rate, and timing to avoid collisions by configuring specific formats and resources for combined SR and ACK/NACK transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SR is transmitted on sPUCCH and collides with PUCCH, then SR transmission is possible, but throughput is reduced due to collision
Solution Approach 1:
The patent merges SR and HARQ-ACK transmissions by consolidating them onto a single channel (PUCCH or sPUCCH) when collisions occur. The UE determines whether to transmit on PUCCH or sPUCCH based on capability and configuration, combining both SR and HARQ-ACK in one transmission to avoid collision while maintaining throughput efficiency.
Solution Approach 2:
The patent implements dynamic resource selection where the UE can adaptively choose between PUCCH and sPUCCH for combined SR and HARQ-ACK transmission based on real-time conditions including UE capability, network configuration, and collision detection. This dynamic approach allows the system to optimize throughput while ensuring reliable SR transmission.
2Reliability
If UE consolidates SR and HARQ feedback on sPUCCH, then collision is avoided, but resource selection complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple sPUCCH resources with different formats and properties before collision occurs. The network provides the UE with a set of configured resources, and the UE selects from these pre-prepared options based on the specific collision scenario, reducing the complexity of real-time resource selection.
Solution Approach 2:
The patent uses parameter changes by selecting different sPUCCH resource formats (e.g., format 2, 3, or 4) based on the number of HARQ bits and coding rate requirements. The UE adjusts transmission parameters such as resource block allocation, cyclic shift, and format selection to match the specific transmission needs, simplifying the decision process through parameter-based selection.
3Reliability
If UE determines sPUCCH resources based on HARQ bits and coding rate, then transmission reliability is improved, but processing time increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple sPUCCH resources with different formats, resource block allocations, and coding rates before the actual transmission is needed. The network provides a set of configured resources that cover various HARQ bit lengths and coding rate scenarios, allowing the UE to quickly select an appropriate pre-configured resource without extensive real-time calculations.
Solution Approach 2:
The patent uses parameter changes by selecting from pre-configured resources based on simple parameter matching (number of HARQ bits, required coding rate). The UE compares the current transmission requirements against the pre-configured resource parameters and selects the matching resource, significantly reducing processing time compared to optimizing parameters in real-time.
Data Source
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AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may identify that a scheduling request (SR) is to be transmitted on a first uplink control channel having a first transmission time interval (TTI) duration and identify that acknowledgment/negative acknowledgment (ACK/NACK) information is scheduled for transmission on a second uplink control channel having a second TTI duration greater than the first TTI duration, where the first uplink control channel and the second uplink control channel overlap in time. The UE may determine that the ACK/NACK information is to be transmitted with the SR on the first uplink control channel based on the overlapping first uplink control channel and second uplink control channel, and may determine resources of the first uplink control channel to be used for transmission of SR and ACK/NACK information. The UE may transmit the SR and the ACK/NACK information on the determined resources.