Dual-Connectivity Radio Bearer State Switching for PDCP Duplication
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Solution Overview
Problem
In dual-connectivity scenarios, the ambiguity arises in determining when to trigger or exit a survival time state for uplink transmissions due to differing HARQ feedback from multiple MAC entities, leading to unclear behavior for data radio bearers.
Innovation Solution
Define triggering and fallback rules based on specific conditions involving both or only one MAC entity's feedback, with pre-configuration by the gNB for the UE to determine state changes, using distinct RLC entity sets for normal and survival time modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PDCP duplication is activated based on dynamic signaling from the base station, then retransmission reliability is improved, but state switching ambiguity occurs in dual-connectivity scenarios
Solution Approach 1:
The patent segments the state management by defining distinct first state and second state for the radio bearer, with clear transition conditions based on MAC entity feedback. This segmentation resolves the ambiguity by creating well-defined state boundaries and transition rules, where the apparatus can clearly determine when to switch states based on whether MAC entities indicate survival time state entry or exit conditions.
2Reliability
If multiple MAC entities provide HARQ feedback in dual-connectivity, then transmission redundancy is improved, but state triggering ambiguity increases
Solution Approach 1:
The patent merges the feedback from multiple MAC entities by requiring that survival time state entry be triggered when MAC entities indicate error conditions, and state exit be triggered when MAC entities indicate successful transmission. This merging approach consolidates multiple feedback sources into unified state transition rules, reducing the complexity of determining state changes despite having multiple MAC entities providing feedback.
Solution Approach 2:
The patent implements a feedback mechanism where MAC entities provide HARQ feedback to the apparatus, which then uses this feedback to determine state transitions. The feedback loop allows the system to adaptively switch between first and second states based on real-time transmission conditions, with clear rules for when to enter or exit survival time state based on the feedback received from MAC entities.
3Reliability
If survival time state triggering is based on MAC entity indications, then transmission reliability is improved, but operational clarity deteriorates
Solution Approach 1:
The patent implements dynamic state switching where the radio bearer can transition between first state and second state based on real-time conditions indicated by MAC entities. The dynamic nature allows the system to adapt to changing transmission conditions while maintaining operational clarity through well-defined transition rules: entering survival time state when MAC entities indicate errors, and exiting when successful transmission is confirmed.
Data Source
AI summary
An apparatus and a method for a wireless communication system is provided, wherein, a number of medium access control entities associated with at least one active radio link control entity of a radio bearer is determined; at least one condition for switching a state associated with the radio bearer based, at least partially, on the determined number of medium access control entities is determined; determining that the determined at least one condition for switching the state associated with the radio bearer is satisfied; and switching the state associated with the radio bearer from a first state to a second state based, at least partially, on determining that the at least one condition for switching the state associated with the radio bearer is satisfied.