BWP Switching for 5G NR Multicast Power Reduction
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Solution Overview
Problem
Current 5G NR multicast and broadcast services face challenges in resource allocation and BWP switching, leading to increased power consumption, signaling overhead, and reduced efficiency, especially when UEs need to receive MBS on the entire component carrier, which is not practical due to high power requirements and manufacturing costs.
Innovation Solution
A group-common resource allocation method and BWP switching method are proposed, where UEs are allocated a unicast BWP with shared resources for MBS, allowing them to stay on the same active BWP for monitoring without switching, and switching to a default BWP when inactive, optimizing resource use and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UEs receive NR MBS on the whole component carrier bandwidth, then MBS reception coverage is improved, but UE power consumption and manufacturing cost increase
Solution Approach 1:
The component carrier bandwidth is divided into multiple bandwidth parts (BWPs), where a first BWP is designated for MBS reception and a second BWP for unicast reception. This segmentation allows the UE to receive MBS on a reduced bandwidth (first BWP) rather than the entire component carrier, thereby reducing power consumption while maintaining MBS reception capability.
Solution Approach 2:
Different bandwidth parts are allocated for different reception purposes: the first BWP is optimized for MBS reception while the second BWP is optimized for unicast reception. This local quality differentiation allows the UE to activate only the necessary BWP for each reception type, reducing overall power consumption while maintaining service quality.
2Productivity
If separate BWPs are configured for MBS and unicast reception, then resource efficiency is improved, but BWP switching complexity increases
Solution Approach 1:
The network pre-configures multiple BWPs (first BWP for MBS, second BWP for unicast) and associates them with specific RNTIs (G-RNTI for MBS, C-RNTI for unicast). This preliminary configuration allows the UE to quickly determine which BWP to use based on the RNTI in the received DCI, avoiding complex real-time decision-making and reducing switching complexity.
Solution Approach 2:
The RNTI acts as an intermediary that links the DCI to the appropriate BWP. When the UE receives a DCI scrambled with G-RNTI, it automatically switches to the first BWP for MBS reception; when scrambled with C-RNTI, it switches to the second BWP for unicast reception. This intermediary mechanism simplifies the BWP switching logic.
3Use of energy by moving object
If BWP switching is implemented for MBS reception, then power consumption is reduced, but BWP switching time and signaling overhead increase
Solution Approach 1:
The network can configure the UE to continuously monitor both the first BWP (for MBS) and second BWP (for unicast) simultaneously by associating different RNTIs with different BWPs. This eliminates the need for time-consuming BWP switching, as the UE maintains continuous reception capability on both BWPs without interrupting service.
Solution Approach 2:
The UE dynamically selects which BWP to actively process based on the RNTI in the received DCI, while maintaining configuration knowledge of both BWPs. This dynamic selection approach allows the UE to minimize active processing on one BWP at a time, reducing power consumption while avoiding full switching overhead through pre-configuration.
Data Source
AI summary
A group-common resource allocation method for multicast and broadcast service (MBS) and related devices are provided. The method includes when there is no data ongoing for MBS and unicast on an active BWP, switching from the active BWP to a default BWP upon expiry of a first MBS bwp-Inactivity Timer for MBS or a bwp-Inactivity Timer for unicast; and monitoring group-common resources on the default BWP for MBS reception. With this method, power consumption for MBS reception is improved.