Semi-Persistent Scheduling for Mobile Device Battery Life
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Solution Overview
Problem
Current wireless communication systems waste battery power in mobile devices due to continuous monitoring for dynamic scheduling grants, especially when few or no grants are received, leading to reduced battery life.
Innovation Solution
Combining semi-persistent scheduling with dynamic scheduling to allocate resources only during awake periods, allowing mobile devices to turn off reception during sleep periods and reducing unnecessary power consumption by aligning semi-persistent and dynamic resource allocations with defined awake periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If continuous monitoring for dynamic scheduling grants is implemented, then resource allocation flexibility is improved, but battery power consumption increases
Solution Approach 1:
The patent implements discontinuous reception (DRX) where the mobile device alternates between awake periods (monitoring for grants) and sleep periods (turning off reception). This periodic monitoring pattern reduces battery power consumption while still allowing the device to receive dynamic scheduling grants when needed, thus resolving the contradiction between continuous monitoring flexibility and power consumption.
2Loss of information
If semi-persistent scheduling is used, then signaling overhead is reduced, but ability to transmit additional packets dynamically is limited
Solution Approach 1:
The patent combines semi-persistent scheduling (which reduces signaling overhead by allocating resources periodically) with dynamic scheduling capabilities (which allow flexible resource allocation for additional packets). During awake periods, the device can receive both semi-persistent allocations and dynamic grants, merging the benefits of reduced signaling overhead with the flexibility to transmit additional packets when needed.
3Duration of action of moving object
If reception is turned off during sleep periods, then battery life is extended, but resource allocation responsiveness decreases
Solution Approach 1:
The patent uses semi-persistent scheduling to pre-allocate resources during awake periods, so that when the device transitions to sleep mode, resources are already reserved for upcoming transmissions. This preliminary resource allocation maintains responsiveness for scheduled traffic while allowing the device to conserve power during sleep periods, as no monitoring is needed for pre-allocated resources.
Data Source
AI summary
Methods of combining semi-persistent resource allocation and dynamic resource allocation are provided. Packets, such as VoIP packets, are transmitted on the uplink and downlink using respective semi-persistent resources. For each mobile device, awake periods and sleep periods are defined. The semi-persistent resources are aligned with the awake periods so that most of the time the mobile device can turn off its wireless access radio during the sleep periods. In addition, signalling to request, and to allocate, resources for additional packets are transmitted during the awake periods, and the resources allocated for the additional packets are within the awake windows.