Radio Terminal Feedback Parameter Autonomy in SC-PTM
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Solution Overview
Problem
In mobile communication systems, multicast/broadcast transmission in LTE networks faces inefficiencies in radio resource utilization due to the inability to dynamically change MBSFN subframes, leading to potential radio resource wastage, especially when compared to single cell Point To Multipoint (SC-PTM) transmission methods.
Innovation Solution
A radio terminal autonomously determines transmission parameters for feedback information on multicast/broadcast data, allowing for efficient use of common resources for NACK transmission in SC-PTM, even in RRC idle states, by using techniques such as timing advance, path loss compensation, cyclic shift, and time-frequency resource allocation to optimize uplink radio resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multicast/broadcast transmission is implemented in LTE networks, then radio resource utilization is improved, but the inability to dynamically change MBSFN subframes causes radio resource wastage
Solution Approach 1:
The patent enables dynamic switching between MBSFN and non-MBSFN subframes, allowing the system to adapt radio resource allocation based on real-time service requirements. The base station can dynamically configure subframe types through RRC signaling, transforming the static MBSFN subframe structure into a dynamic one that optimizes resource utilization while avoiding wastage.
Solution Approach 2:
The patent changes the configuration parameters of subframes by allowing the base station to indicate via RRC signaling whether a subframe should be treated as MBSFN or non-MBSFN. This parameter change enables flexible resource allocation where the same physical resources can be dynamically reassigned based on current multicast/broadcast needs versus unicast requirements.
2Reliability
If feedback information is transmitted using dedicated resources, then transmission reliability is improved, but resource allocation complexity increases
Solution Approach 1:
The patent makes uplink resources universal by allowing the same physical uplink resources to serve multiple purposes - both unicast feedback and multicast/broadcast feedback. The base station configures resource pools that can be dynamically assigned to different feedback types, eliminating the need for separate dedicated resources for each feedback channel and reducing overall resource allocation complexity.
Solution Approach 2:
The patent creates a shared resource pool configuration that can be copied and reused for different feedback scenarios. Instead of creating unique dedicated resources for each feedback type, the system uses configurable resource pools that can be instantiated and assigned dynamically, simplifying the resource management architecture.
3Area of stationary object
If radio terminals in RRC idle state can receive multicast/broadcast data, then service coverage is improved, but feedback transmission capability is lost
Solution Approach 1:
The patent enables radio terminals in RRC idle state to autonomously transmit feedback information using autonomously selected resources from configured pools. The terminal self-manages the feedback transmission process by selecting appropriate resources and timing based on pre-configured parameters, eliminating the need for active network control and maintaining feedback capability while in idle state.
Solution Approach 2:
The patent performs preliminary configuration of feedback resource pools and parameters while the terminal is in idle state. The base station pre-configures the terminal with resource pool information, timing advance parameters, and other necessary feedback transmission parameters before the terminal needs to send feedback, enabling immediate feedback capability without requiring state transition.
Data Source
AI summary
A radio terminal according to one embodiment comprises: a controller configured to perform a process of: receiving, if the radio terminal is in a specific state different from an RRC connected state, multicast/broadcast data transmitted from a base station; and transmitting feedback information on the multicast/broadcast data to the base station. The controller is configured to autonomously determine a transmission parameter to be used for transmitting the feedback information and transmits the feedback information by using the determined transmission parameter.