Radio Terminal Coverage Enhancement for MBMS Service
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Solution Overview
Problem
Radio terminals for Machine Type Communication (MTC) and Internet of Things (IoT) services face challenges in achieving low cost, wide coverage, and low power consumption, particularly in scenarios where normal reception of MBMS services is not possible, requiring enhanced coverage techniques like repetition.
Innovation Solution
A radio terminal and base station configuration that includes a receiver, controller, and transmitter, where the controller determines the need for coverage enhancement and transmits a notification to the base station, which applies repetition techniques for MBMS service distribution, prioritizing cells with better radio quality for MBMS service reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coverage enhancement technique including repetition is applied to radio terminal, then coverage area and reliability are improved, but power consumption and device complexity increase
Solution Approach 1:
The system dynamically changes the coverage enhancement level parameter based on reception conditions. When MBMS service reception fails or is requested, the radio terminal determines a higher coverage enhancement level requiring more repetitions, and notifies the base station. This parameter adjustment resolves the contradiction by adapting repetition levels to actual needs rather than using fixed high repetition counts.
Solution Approach 2:
The coverage enhancement level is made dynamic rather than static. The radio terminal continuously monitors reception status and adjusts the coverage enhancement level accordingly. This dynamic adaptation allows the system to use higher repetition counts only when necessary for reliable reception, reducing unnecessary power consumption while maintaining reliability when needed.
2Area of stationary object
If coverage enhancement technique including repetition is applied to radio terminal, then coverage area is improved, but device complexity increases
Solution Approach 1:
The system uses parameter changes to manage complexity. Instead of implementing complex adaptive algorithms, the radio terminal determines coverage enhancement level based on simple reception status checks (whether MBMS service is received or requested). This keeps the device relatively simple while still achieving wide coverage through parameter adjustment.
Solution Approach 2:
The coverage area is segmented into different coverage enhancement levels (e.g., normal coverage, enhanced coverage level 1, enhanced coverage level 2). Each level corresponds to different repetition counts and reception configurations. This segmentation allows the system to manage complexity by handling each coverage level with predefined parameters rather than continuous adaptation.
3Measurement precision
If cell reselection is performed based on ranking for coverage enhancement, then reception quality is improved, but service continuity may be interrupted
Solution Approach 1:
The system performs preliminary action by determining the coverage enhancement level before cell reselection. The radio terminal checks whether it is receiving or interested in receiving MBMS service, and if so, prioritizes cells that provide the MBMS service regardless of ranking. This preliminary check ensures service continuity is maintained before making reselection decisions.
Solution Approach 2:
The system uses feedback from MBMS service reception status to guide cell reselection. When the radio terminal detects it is receiving or interested in MBMS service, it feeds this information back into the cell selection process by prioritizing cells providing the MBMS service. This feedback mechanism resolves the contradiction by ensuring service continuity while still allowing radio quality optimization when MBMS service is not the priority.
Data Source
AI summary
A radio terminal according to one embodiment comprises: a receiver configured to receive an MBMS service distributed from a base station by using a coverage enhancement technique including a repetition; a controller configured to determine whether or not a predetermined event occurs; and a transmitter configured to transmit a notification on a coverage enhancement level required by the radio terminal to the base station, in response to occurrence of the predetermined event. The predetermined event includes transmission of the notification being requested from the base station or normal reception of the MBMS service not being possible.