UE DRX Control with sTTI for Latency and Power Trade-off
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Solution Overview
Problem
Current wireless communication networks face challenges in reducing packet data latency and improving radio resource efficiency, particularly in LTE protocols, due to inefficiencies in data transmission and control signaling, which affect power consumption and responsiveness.
Innovation Solution
Implementing a method for user equipment devices to operate with short Transmission Time Intervals (sTTIs) and connected mode discontinuous reception (DRX), where devices monitor transmissions from a radio access network node for UE-specific messages containing control information, allowing for reduced power consumption and efficient resource allocation by distinguishing between slow and fast grant messages within subframes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If discontinuous reception (DRX) is used to reduce power consumption by increasing sleep mode time, then power consumption is reduced, but packet data latency increases due to longer wake-up intervals
Solution Approach 1:
The patent segments the DRX cycle into distinct phases: a first part where the UE monitors for wake-up indications, and a second part where the UE can remain in sleep mode. This segmentation allows the UE to selectively activate monitoring only when necessary, reducing overall power consumption while maintaining responsiveness to urgent data transmissions.
Solution Approach 2:
The patent introduces dynamic adjustment of DRX parameters based on network conditions and UE activity patterns. The network can configure different DRX cycles and wake-up indication mechanisms dynamically, allowing the system to adapt between power-saving mode and low-latency mode as needed, thus resolving the contradiction between power consumption and latency.
2Loss of time
If short Transmission Time Interval (sTTI) is used to reduce packet data latency, then latency is reduced, but device complexity increases due to additional monitoring requirements
Solution Approach 1:
The patent extracts the wake-up indication function from the regular data transmission process by introducing a separate, dedicated wake-up indication mechanism. This allows the UE to monitor only for these simplified indications during DRX active periods without needing to decode full control channels, thereby reducing device complexity while maintaining the low-latency benefits of sTTI.
Solution Approach 2:
Instead of requiring full monitoring of all control channels during each sTTI opportunity, the patent implements partial monitoring where the UE only checks for wake-up indications during specific portions of the DRX cycle. This partial action approach maintains latency performance while significantly reducing the monitoring burden and device complexity.
3Reliability
If the UE monitors the entire subframe for control information, then control information reliability is improved, but power consumption increases due to extended active reception time
Solution Approach 1:
The patent implements preliminary action by having the network send a wake-up indication before the actual data transmission. This allows the UE to prepare for upcoming transmissions by activating its receiver in advance during the first part of the subframe, ensuring reliable reception of subsequent control information while limiting the active reception window to only when necessary, thus reducing overall power consumption.
Data Source
AI summary
A method may be provided to operate a user equipment device, UE. The method may comprise, when operating with a short Transmission Time Interval (sTTI), and when using connected mode discontinuous reception, DRX, monitoring transmissions from a radio access network node during a first part of a subframe for a UE-specific message for the UE containing first control information. If no UE-specific message for the UE containing first control information is received, the UE may be inactive during a second part of the subframe following after the first part of the subframe. If the UE receives the UE-specific message containing first control information, it may monitor the second part of the subframe for a message containing second control information, for use in receiving or transmitting data from or to the radio access network node.