Multicast Traffic Delivery Across RRC States Using Dual PDCCHs
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Solution Overview
Problem
Existing communication technologies are limited in delivering multicast and/or broadcast traffic to terminal devices in different Radio Resource Control (RRC) states, with only connected devices capable of receiving multicast, while idle or inactive devices are excluded.
Innovation Solution
A method and apparatus for transmitting multicast and/or broadcast traffic using multiple physical downlink control channels and a shared channel to subsets of devices in different RRC states, allowing efficient delivery to both connected and idle/inactive devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multicast traffic is transmitted using a single physical downlink control channel, then the system complexity is reduced, but the ability to deliver traffic to devices in different RRC states is limited
Solution Approach 1:
The patent segments the control channel transmission by introducing multiple physical downlink control channels (first PDCCH and second PDCCH) with different functionalities. The first PDCCH handles connected mode devices while the second PDCCH handles idle/inactive mode devices, allowing tailored delivery mechanisms for different RRC states without overwhelming system complexity
Solution Approach 2:
The patent applies local quality by providing different control information formats and delivery mechanisms tailored to specific RRC states. Connected mode devices receive control information suitable for their active state, while idle/inactive devices receive optimized control information that conserves their power, ensuring each device type receives appropriately customized control signals
2Adaptability or versatility
If multicast traffic is delivered to all terminal devices regardless of RRC state, then the coverage is improved, but the resource efficiency deteriorates due to uniform treatment of all devices
Solution Approach 1:
The patent implements local quality by transmitting different control information through different PDCCH channels based on the RRC state of target devices. Idle and inactive devices receive control information via the second PDCCH that is optimized for their power-constrained state, while connected devices receive control information via the first PDCCH, ensuring each device type receives appropriately customized control signals that match their operational characteristics
Solution Approach 2:
The patent applies dynamics by making the control channel selection adaptive to the RRC state of terminal devices. The system dynamically determines which PDCCH channel to use based on whether the target device is in connected, idle, or inactive state, allowing the delivery mechanism to flexibly adapt to changing device states and optimize resource usage accordingly
3Ease of operation
If a single downlink control information format is used for all devices, then the processing complexity is reduced, but the quality of service for connected devices deteriorates
Solution Approach 1:
The patent segments control information delivery by creating distinct control information formats and transmission channels: first downlink control information via first PDCCH for connected mode devices, and second downlink control information via second PDCCH for idle/inactive mode devices. This segmentation allows each format to be optimized for its specific use case without compromising the other
Solution Approach 2:
The patent applies local quality by providing different control information formats tailored to specific RRC states. Connected mode devices receive control information with features optimized for their active state (higher reliability, more detailed scheduling information), while idle/inactive devices receive simplified control information that reduces their processing burden and power consumption
Data Source
AI summary
Embodiments of the present disclosure relate to delivery mode of traffic for terminal devices in different RRC states. A first device determines, based on at least one criterion, to transmit multicast and/or broadcast traffic to a plurality of second devices in a first mode of delivery; and transmit the multicast and/or broadcast traffic to the plurality of second devices in the first mode of delivery by at least: transmitting, to a first subset of second devices among the plurality of second devices, a first downlink control information for the multicast and/or broadcast traffic using a first physical downlink control channel; transmitting, to a second subset of second devices among the plurality of second devices, a second downlink control information for the multicast and/or broadcast traffic using a second physical downlink control channel; and transmitting, to the plurality of second devices, the multicast and/or broadcast traffic using a physical downlink shared channel. In this way, it is possible to transmit the multicast and/or broadcast traffic from a first device to a plurality of second devices in a more radio efficient manner.