Multicast Coverage Level Optimization in NB-IoT
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Solution Overview
Problem
In Narrowband Internet of Things (NB-IoT), when a network device transmits a service in multicast mode, not all terminal devices need the service, leading to wastage of radio resources due to the use of the highest coverage level for all devices, even if only a subset has lower coverage levels.
Innovation Solution
A method where a group communication application server determines the multicast coverage level based on the subscription terminals' coverage levels, sending a multicast transmission indicator through BM-SC, MME, and MCE to instruct the network device to use appropriate transmission parameters, optimizing resource usage by adjusting the coverage level for each terminal device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the network device transmits the service in multicast mode by using the highest coverage level supported by the network device to ensure all terminal devices can reliably receive the service, then the reliability of data transmission is improved, but a large quantity of radio resources are wasted when terminal devices with lower coverage levels receive the service
Solution Approach 1:
The patent segments the multicast service transmission by creating separate multicast sessions for different coverage levels. The network device divides terminal devices into different groups based on their coverage levels and transmits the service using multiple multicast transmission indicators, each corresponding to a specific coverage level. This allows terminal devices to receive services appropriate to their coverage capabilities without wasting radio resources on unnecessary high-coverage transmissions.
Solution Approach 2:
The patent implements dynamic adjustment of multicast coverage levels based on the actual needs of terminal devices. The group communication application server determines the appropriate multicast coverage level for each terminal device based on its coverage capability, and the network device dynamically selects transmission parameters accordingly. This dynamic approach ensures that radio resources are used efficiently while maintaining reliable service delivery to all terminal devices regardless of their coverage levels.
2Reliability
If the network device uses a fixed highest coverage level for multicast transmission, then all terminal devices can receive the service reliably, but the adaptability to different terminal device coverage levels is reduced
Solution Approach 1:
The patent applies local quality by assigning different multicast coverage levels to different terminal devices based on their specific coverage capabilities. Instead of using a uniform highest coverage level for all devices, the network device configures separate multicast transmission parameters for each coverage level group. This allows each terminal device to receive services with quality appropriate to its local coverage conditions, improving both reliability and adaptability.
Solution Approach 2:
The patent changes the transmission parameters dynamically based on terminal device coverage levels. The group communication application server determines the appropriate multicast coverage level for each terminal device, and the network device adjusts transmission parameters such as repetition counts and modulation schemes accordingly. This parameter adaptation ensures that services are transmitted with optimal quality for each device's coverage capabilities while avoiding unnecessary resource consumption.
Data Source
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AI summary
This application provides a service transmission method and a wireless communications device. The method includes: determining, by a group communication application server, a multicast coverage level of a multicast service, where the multicast coverage level is a coverage level used when a network device corresponding to the cell transmits the service in multicast mode; and sending, by the group communication application server, a multicast transmission indicator to a network device of the multicast service through a BM-SC, an MME, and an MCE, where the multicast coverage level indication information corresponds to the multicast coverage level. According to the method and the wireless communications device provided in this application, a network element in a core network may determine a multicast coverage level based on a coverage level of a subscription terminal, so that a network device transmits a service in multicast mode by using a proper service coverage level, thereby reducing wasteful radio resources when the network device transmits the service in multicast mode.