UE Downlink Reception DRX Timer Management
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Solution Overview
Problem
The increasing number of user equipment (UEs) in wireless communication systems requires more efficient use of limited radio resources for data and control information transmission, while also necessitating reduced latency and improved performance for applications sensitive to delay, particularly with the rise of smart devices and massive machine-type communication.
Innovation Solution
Implementing a low-cost, low-complexity UE that can communicate efficiently with a base station using narrowband communication, optimizing data transmission and reception, and employing Discontinuous Reception (DRX) timers to manage HARQ processes effectively, thereby reducing latency and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of user equipments (UEs) increases to support more services and devices, then service availability and connectivity increase, but radio resource availability per UE decreases and system complexity increases
Solution Approach 1:
The patent segments the downlink reception process into multiple HARQ processes that can operate in parallel. By dividing the reception task across multiple processes (e.g., HARQ process 0, 1, 2, 3), the system can handle multiple UEs simultaneously without increasing per-UE complexity, thus supporting more services while maintaining manageable system complexity
Solution Approach 2:
The patent implements periodic HARQ retransmission mechanisms with configured timing relationships (K1, K2, K3 offsets). This periodic structure allows the system to efficiently manage retransmissions for multiple UEs using predictable resource patterns, enabling scalable support for increasing numbers of devices without linearly increasing system complexity
2Adaptability or versatility
If traditional wideband communication is used to maintain compatibility with legacy systems, then legacy system compatibility is maintained, but power consumption increases and latency is higher
Solution Approach 1:
The patent applies local quality by enabling UEs to operate in narrowband mode for specific communication tasks while maintaining the capability to switch to wideband mode when needed. This allows power-efficient narrowband operation for small data transmissions and low-complexity applications, while preserving legacy compatibility through selective wideband operation when required
Solution Approach 2:
The patent implements dynamic bandwidth adaptation where the UE can transition between narrowband and wideband modes based on traffic requirements. The system dynamically adjusts the reception bandwidth and HARQ process configuration, allowing low-power narrowband operation for small data while maintaining the ability to use wideband mode for larger transmissions or legacy compatibility requirements
3Use of energy by moving object
If Discontinuous Reception (DRX) timers are used to reduce power consumption, then power efficiency improves, but latency increases for data reception
Solution Approach 1:
The patent configures preliminary HARQ timing relationships (K1, K2, K3 offsets) that allow the UE to predict when downlink data will be transmitted and when acknowledgments are expected. This preliminary configuration enables the DRX timer to be optimized - the UE can enter sleep mode knowing exactly when to wake for expected transmissions, reducing power consumption while minimizing latency through accurate timing prediction
Solution Approach 2:
The patent implements feedback mechanisms where the UE reports HARQ acknowledgment status and buffer status to the base station. This feedback allows the network to adjust DRX timer configurations and HARQ retransmission timing dynamically, optimizing the balance between power savings from DRX and latency requirements for timely data delivery
4Productivity
If multiple HARQ processes are implemented to increase throughput, then system throughput improves, but device complexity and processing requirements increase
Solution Approach 1:
The patent segments the HARQ functionality into multiple independent processes, each handling specific downlink transmissions. By dividing the throughput requirement across multiple parallel HARQ processes rather than using one complex sequential process, the system achieves high throughput while keeping each individual HARQ process relatively simple and manageable
Solution Approach 2:
The patent establishes periodic patterns for HARQ process usage with configured timing offsets. This periodic structure allows the UE to reuse HARQ process identifiers in a predictable cycle, reducing the need for complex process management logic while maintaining high throughput through efficient parallel operation of multiple processes
Data Source
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AI summary
A user equipment (UE) starts a downlink (DL) discontinuous reception (DRX) retransmission timer for a DL hybrid automatic repeat and request (HARQ) process of the UE. The UE monitors a physical downlink control channel (PDCCH) while the DL DRX retransmission timer for the DL HARQ process is running. The UE stops the DL DRX retransmission timer for the DL HARQ process when the UE receives a PDCCH indicating a uplink (UL) transmission.