SPS Activation Request for MBS Multicast in RRC Inactive
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Solution Overview
Problem
Current wireless communication technologies face challenges in allowing user equipment (UE) to receive multicast and broadcast services in an RRC_INACTIVE state, leading to issues with missed scheduling activations and inefficient data reception due to the lack of feedback mechanisms and reliance on PDCCH for SPS transmission activation.
Innovation Solution
The method involves a user equipment sending a signal to a network element to request scheduling activation using a PRACH resource or RRCResumeRequest message, allowing for semi-persistent scheduling (SPS) activation even in an inactive state, and utilizing a group common physical downlink control channel for data reception, ensuring awareness of SPS transmission activation without relying on PDCCH feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If user equipment relies on PDCCH for SPS transmission activation in RRC_INACTIVE state, then multicast service reception is enabled, but scheduling activation may be missed due to lack of feedback mechanisms
Solution Approach 1:
The patent implements a feedback mechanism where the UE sends a confirmation message (e.g., HARQ-ACK or specific indication) to the network element after successfully receiving and processing the SPS activation indication. This feedback loop ensures that the network can verify whether the UE has correctly received the scheduling activation, thereby preventing information loss and improving reliability of multicast service reception in RRC_INACTIVE state.
Solution Approach 2:
The network element proactively sends the SPS activation indication to the UE before actual multicast data transmission begins. This preliminary action allows the UE to prepare its reception parameters in advance, ensuring that when multicast data arrives, the UE is already configured to receive it correctly, thus preventing missed activations.
2Reliability
If user equipment transitions to RRC_CONNECTED state to receive multicast services, then reliable data reception is achieved, but power consumption increases and scalability decreases
Solution Approach 1:
The patent enables the UE to dynamically receive multicast services in RRC_INACTIVE state using SPS activation, allowing the system to adapt the UE's operational state based on service requirements. The UE can remain in the lower-power RRC_INACTIVE state while still receiving multicast data through pre-configured SPS resources, thus reducing power consumption while maintaining reliable reception through the activation indication mechanism.
Solution Approach 2:
The patent changes the operational parameters of the UE by enabling SPS reception in RRC_INACTIVE state, which has different power consumption characteristics compared to RRC_CONNECTED state. By adjusting the reception mode and using pre-configured resources, the system achieves reliable multicast reception with reduced energy usage.
3Reliability
If user equipment uses dedicated PRACH resources for SPS activation request, then activation reliability improves, but device complexity and resource overhead increase
Solution Approach 1:
The patent makes the dedicated PRACH resources serve multiple functions: they are used both for initial access and for sending SPS activation requests. This multi-functionality reduces the need for separate dedicated resources solely for SPS activation, thereby limiting the increase in device complexity and resource overhead while still improving activation reliability through the use of dedicated uplink resources.
Data Source
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AI summary
A method comprising determining with an apparatus, where the apparatus comprises a user equipment in an inactive state or an idle state, that a scheduling is activated in a cell, where the user equipment has not received scheduling activation regarding the scheduling activated in the cell, and where the user equipment has selected the cell; based upon the determining that the scheduling is activated in the cell, sending, with the user equipment, a signal to a network element, where the signal is configured to request activation of the scheduling; receiving scheduling activation from the network element in response to the signal, and upon receiving the scheduling activation, receiving data according to the scheduling.