Dormant DRX State for Multi-Carrier Power Management
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Solution Overview
Problem
Designing an efficient LTE mobile terminal capable of multi-carrier operations is challenging due to increased power consumption and complexity in managing non-contiguous spectrum, particularly in scenarios where UEs are not scheduled frequently, leading to unnecessary power waste and battery drain.
Innovation Solution
Introducing a new 'dormant' DRX state for non-anchor carriers in multi-carrier systems, allowing them to stop monitoring system signaling, with transitions controlled by timers or explicit signaling from anchor carriers, enabling power savings without compromising quick data transmission resumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-carrier operations are implemented in LTE mobile terminals, then downlink throughput and data rates are improved, but power consumption and device complexity increase
Solution Approach 1:
The patent implements dynamic DRX cycle adjustment where the mobile terminal can switch between short DRX cycles and long DRX cycles based on scheduling activity. When no scheduling is detected during a short DRX cycle, the terminal transitions to a long DRX cycle with longer sleep periods, thereby reducing power consumption while maintaining the ability to quickly resume data transmission when needed
Solution Approach 2:
The patent employs periodic DRX cycles with defined on-duration and sleep periods. During sleep periods, the terminal turns off reception circuits for non-anchor carriers, periodically waking up only to monitor anchor carrier for scheduling decisions. This periodic operation pattern reduces average power consumption while ensuring data transmission can be resumed efficiently
2Productivity
If multi-carrier operations are implemented in LTE mobile terminals, then downlink throughput and data rates are improved, but device complexity increases
Solution Approach 1:
The patent segments the multi-carrier system into anchor carriers and non-anchor carriers. Anchor carriers maintain continuous monitoring and full functionality, while non-anchor carriers use DRX cycles with periodic sleep modes. This segmentation allows the terminal to manage complexity by treating different carriers differently, reducing overall system complexity while maintaining high throughput capabilities
Solution Approach 2:
The patent applies different operational qualities to different carriers: anchor carriers receive full attention with continuous monitoring, while non-anchor carriers receive reduced attention during sleep periods. This local quality differentiation optimizes the balance between throughput and complexity by concentrating resources where needed most
3Use of energy by moving object
If DRX cycles are used to reduce power consumption, then power efficiency is improved, but data transmission responsiveness deteriorates
Solution Approach 1:
The patent implements dynamic transition between short and long DRX cycles based on scheduling activity. When activity is detected, the system switches to shorter cycles for faster responsiveness. When inactive, it uses longer cycles for better power efficiency. This dynamic adaptation resolves the contradiction by adjusting responsiveness to match actual data transmission needs
Solution Approach 2:
The patent uses the short DRX cycle as a preliminary state before transitioning to the long DRX cycle. This preliminary action ensures that if data transmission is needed, the terminal is already in a responsive state with shorter sleep periods, ready to quickly resume communication without having to wake up from a deep sleep state
Data Source
AI summary
The present invention relates to methods and arrangements in a multi-carrier system. It also assumes independent DRX (Discontinuous reception) functionality on respective component carriers and the possibility for one carrier, e.g. the anchor carrier to initiate a change of DRX state for another component carrier. The basic concept of the present invention is to introduce a new “dormant” state in the DRX logic, whereby the dormant state can be used for non-anchor carrier components. The dormant DRX state implies that a carrier of a UE having this state is not required to monitor system signaling. In embodiments of the present invention this new state is introduced for a particular component carrier (e.g. non-anchor component carrier) for a UE operating in a multi-carrier system, and how to perform the transitions to and from the dormant DRX state implicitly, e.g. based on configured timer(s) for the component carrier or explicit signaling in a different (e.g. anchor) component carriers.