Semi-Persistent Scheduling Release with DRX Command
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Solution Overview
Problem
In wireless communication systems, especially in 3GPP LTE, there is a need to efficiently release semi-persistent scheduling resources and transition user terminals to an energy-saving mode, such as Discontinuous Reception (DRX), to conserve battery power when no data is expected to be transmitted for a while, while minimizing the number of control channel messages required.
Innovation Solution
A method and apparatus that transmit a Physical Downlink Control Channel (PDCCH) message commanding the release of semi-persistent scheduling resources and simultaneously include a command for switching to the DRX mode, with the release message being associated with a Physical Downlink Shared Channel (PDSCH) transmission, allowing the user terminal to immediately enter the DRX mode upon decoding the message, thereby reducing power consumption and minimizing additional transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate PDCCH and PDSCH transmissions are used to release SPS resources and command DRX mode switching, then control information can be clearly delivered, but the number of transmissions increases and power consumption rises
Solution Approach 1:
The patent combines the SPS release command and DRX mode switching command into a single PDCCH transmission. The PDCCH message includes both the SPS release indication and a pointer to PDSCH resources, while the PDSCH carries the DRX command. This merging eliminates the need for separate transmissions, reducing power consumption while ensuring reliable delivery of both control information elements.
Solution Approach 2:
The PDCCH transmission is designed to serve multiple functions simultaneously: it releases SPS resources, indicates PDSCH association, and triggers DRX mode switching. By making the control channel multi-functional, the patent reduces the total number of transmissions required, thereby reducing energy loss while maintaining comprehensive control information delivery.
2Reliability
If multiple control channel transmissions are used to release SPS resources and switch to DRX mode, then complete control information can be delivered, but transmission overhead increases
Solution Approach 1:
The patent merges multiple control functions into a single PDCCH transmission structure. The PDCCH carries both the SPS release command and the DRX switching command, with appropriate field indications. This consolidation reduces transmission overhead by eliminating redundant control channel messages while ensuring that all necessary control information is reliably delivered through the unified structure.
Solution Approach 2:
The control channel structure is designed to perform multiple functions simultaneously - releasing SPS resources, indicating PDSCH association, and commanding DRX mode switching. This multi-functional design reduces the overall transmission overhead by consolidating what would otherwise require separate messages into a single efficient transmission.
3Loss of energy
If PDCCH message is associated with PDSCH transmission, then DRX command can be included efficiently, but the message structure becomes more complex
Solution Approach 1:
The patent associates the PDCCH message with PDSCH transmission to efficiently deliver the DRX command. The PDCCH includes a pointer to PDSCH resources, and the PDSCH carries the DRX command. This association allows the system to leverage the existing PDCCH-PDSCH structure for power-efficient communication while managing the message structure complexity through standardized field definitions and clear association indicators.
Data Source
AI summary
Certain aspects of the present disclosure relate to a technique for releasing semi-persistent scheduling resources and for immediate entering an energy saving mode of operation at a user terminal.