UE–Base Station Feedback for Reliable MBMS Multicast
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Solution Overview
Problem
The LTE communication system lacks a specified feedback mechanism for multicast services like MBMS, leading to unreliable autonomous re-transmissions and link adaptations due to the absence of feedback from multiple receivers, resulting in resource waste or data loss.
Innovation Solution
Implementing a feedback assisted multicast mechanism where user equipment (UE) provides HARQ ACK/NACK or CSI feedback to the base station, using implicitly or explicitly indicated feedback resources, allowing the base station to determine re-transmissions or adjust modulation coding schemes based on UE feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If autonomous re-transmissions and link adaptations are used without feedback, then the system can operate without complex feedback mechanisms, but reliability deteriorates due to unnecessary re-transmissions or inaccurate MCS selection
Solution Approach 1:
The patent implements a feedback mechanism where UEs send feedback messages to the base station indicating the reliability of the MBMS connection. The base station uses this feedback to determine whether to re-transmit data or adjust MCS, resolving the contradiction by introducing controlled feedback to improve reliability while managing complexity through selective feedback collection and processing.
2Measurement precision
If feedback messages are collected from multiple UEs, then transmission reliability improves through accurate link adaptation, but device complexity increases due to feedback resource management
Solution Approach 1:
The patent segments the feedback process by having different UEs determine feedback resources independently based on receiving MBMS data. Each UE autonomously selects feedback resources from available options, dividing the complex feedback management task into individual UE decisions rather than requiring centralized coordination of all feedback resources.
Solution Approach 2:
UEs self-determine their feedback resources based on the MBMS data they receive, without requiring the base station to explicitly allocate specific resources to each UE. This self-service approach reduces the base station's complexity in managing feedback resources while still collecting necessary feedback from multiple UEs for accurate link adaptation.
Data Source
AI summary
The disclosure is directed to a user equipment and a base station for implementing a feedback assisted multicast. In an aspect, the disclosure is directed to a UE which includes not limited to a transmitter, a receiver, and a hardware processor coupled to the transmitter and the receiver and configured to establish a MBMS connection for receiving a MBMS data, receive, through the receiver, the MBMS data after establishing the MBMS connection, determine a feedback resource based on receiving the MBMS data, and transmit, through the transmitter, a feedback message to indicate a reliability of the MBMS connection by using the feedback resource.