Dynamic HARQ Process Scheduling for Unlicensed IoT
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication systems face challenges in efficiently managing ACK/NACK reporting in unlicensed IoT systems with long transmission durations, particularly in terms of coverage and power consumption, due to limitations in scheduling and resource allocation.
Innovation Solution
The method involves executing an LBT protocol to access shared spectrum, receiving RRM measurements, estimating the number of repetitions for scheduling IoT devices, configuring the maximum number of HARQ processes based on these measurements, and sending downlink grants on PDCCH, allowing for joint scheduling of HARQ processes across multiple TTIs and bundling ACK/NACK reports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of HARQ processes is increased to improve scheduling flexibility and coverage, then coverage is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent dynamically configures the maximum number of HARQ processes based on RRM measurements and estimated repetition counts. The base station adjusts the HARQ process limit adaptively according to channel conditions and device capabilities, rather than using a fixed high value, thereby improving coverage when needed while reducing complexity when conditions permit.
Solution Approach 2:
The patent changes the parameter of maximum HARQ processes from a static configuration to a dynamic one that varies based on RRM measurements and repetition estimates. This parameter adjustment allows the system to optimize between coverage and device complexity by setting appropriate limits based on actual channel conditions.
2Adaptability or versatility
If the number of HARQ processes is increased to improve scheduling flexibility, then scheduling flexibility is improved, but device complexity increases
Solution Approach 1:
The system dynamically adjusts the maximum number of HARQ processes based on RRM measurements and repetition estimates, providing scheduling flexibility when channel conditions warrant it while reducing complexity when conditions are favorable, thus adapting to varying operational requirements.
Solution Approach 2:
The maximum HARQ process parameter is changed from a fixed value to a dynamically determined value based on RRM measurements and repetition counts, enabling the system to achieve scheduling flexibility only when necessary rather than maintaining high flexibility continuously, thereby reducing overall device complexity.
3Reliability
If ACK/NACK reporting is performed for each HARQ process separately, then reliability is improved, but power consumption and overhead increase
Solution Approach 1:
The patent bundles multiple ACK/NACK reports together in a single transmission rather than sending them separately for each HARQ process. This combining approach maintains reliability by ensuring all acknowledgments are transmitted while significantly reducing the number of separate transmissions required, thereby lowering power consumption and reducing signaling overhead.
Solution Approach 2:
The bundled ACK/NACK reporting mechanism serves multiple functions simultaneously: it provides reliability feedback for multiple HARQ processes while reducing power consumption and overhead, making the reporting system more efficient across multiple performance dimensions.
4Reliability
If LBT protocol is executed before each transmission to access shared spectrum, then spectrum access reliability is improved, but transmission duration and power consumption increase
Solution Approach 1:
The LBT protocol is executed in advance before transmission to secure spectrum access and reduce contention. By performing the listen-before-talk check beforehand, the system ensures reliable spectrum access while minimizing the duration of actual data transmission, as the LBT procedure is performed only once before the transmission burst rather than continuously during transmission.
Data Source
AI summary
Certain aspects of the present disclosure relate to methods and apparatus for receiving ACK/NACK reporting in unlicensed IoT systems with long transmission durations. In one example, an eNodeB executes an LBT protocol to gain access to a channel of a shared spectrum, receives radio resource management (RRM) measurement reports from an IoT-U, estimates a number of repetitions used to schedule the IoT-U based on the RRM measurement, and configures the maximum number of HARQ processes that can be scheduled in a frame based on the RRM measurements and the estimate of the repetitions.