Adaptive HARQ for Half-Duplex Devices
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Solution Overview
Problem
Battery and antenna constrained devices in wireless communication systems, such as those using LTE, face challenges in maintaining continuous uplink transmissions due to peak current limitations, leading to restricted duty cycles and impaired hybrid automatic repeat request (HARQ) processes.
Innovation Solution
The implementation of adaptive HARQ techniques and improved communication methods that allow user equipment (UE) to manage uplink transmissions by determining signal-to-interference-plus-noise ratio (SINR) and adjusting transmission schedules, enabling efficient data and ACK/NACK transmission across multiple sub-frames while aligning with base station processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous uplink transmissions are implemented, then communication reliability is improved, but peak current consumption increases beyond device limitations
Solution Approach 1:
The patent implements periodic HARQ processes with structured transmission intervals, where the UE transmits uplink data in periodic sub-frames according to a configured uplink grant pattern. This periodic action allows the device to maintain communication reliability through regular transmissions while controlling peak current consumption by leaving gaps between transmissions.
Solution Approach 2:
The patent introduces dynamic adaptation of HARQ parameters including variable timing offsets (k values), adjustable uplink grant periodicity, and flexible redundancy version selection. These dynamic adjustments allow the system to optimize the balance between communication reliability and power consumption based on current channel conditions and device battery status.
2Use of energy by moving object
If transmission duty cycle is reduced to conserve power, then energy consumption is improved, but HARQ process efficiency deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-configuring HARQ parameters, uplink grants, and timing relationships before actual data transmission begins. The base station provides advance scheduling information including timing offsets and redundancy versions, allowing the UE to prepare transmission buffers and maintain synchronization without requiring continuous high-power operation.
Solution Approach 2:
The patent implements feedback mechanisms where the base station monitors uplink transmission quality and adjusts HARQ parameters accordingly. Through downlink acknowledgments and scheduling requests, the system receives feedback on transmission success and channel conditions, enabling adaptive optimization of duty cycle and transmission power to maintain HARQ efficiency while conserving energy.
3Productivity
If adaptive HARQ parameters are implemented, then transmission efficiency is improved, but system complexity increases
Solution Approach 1:
The patent implements parameter changes by dynamically adjusting HARQ timing offsets (k values), uplink grant periodicity, and redundancy versions based on channel conditions and device capabilities. These parameter changes are signaled through standardized LTE messaging protocols, allowing efficient adaptation without requiring complex custom processing logic in the UE.
Data Source
AI summary
A user equipment (UE) implements improved communication methods which enable uplink (UL) transmissions consistent with an UL timeline. The UE may have a transmit duty cycle and may transmit acknowledge/negative acknowledge messages to a base station according to the transmit duty cycle. Additionally, the UE may be configured to determine signal-to-interference-plus noise ratio (SINR) between the UE and the base station and compare SINR to a threshold. The UE may transmit redundancy versions of data in consecutive sub-frames with a duty cycle of two transmissions per X+1 sub-frames if SINR is equal or above the threshold and redundancy versions using a duty cycle of one transmission per X sub-frames if SINR is below the threshold. Further, the UE may be configured to communicate a number of UL HARQ processes supported by the UE, receive first information in a first sub-frame, and send second information X sub-frames after the first sub-frame.