Radio Link Failure Detection in Multi-Carrier Uplink Systems
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Solution Overview
Problem
Existing radio link failure detection mechanisms in 5G/New Radio (NR) networks with supplementary uplink (SUL) carriers are inadequate, leading to inefficiencies in handling radio link failures due to the mismatch between NR UL and SUL carriers, particularly in high-frequency deployments where coverage issues arise.
Innovation Solution
A method for user equipment (UE) and base stations to monitor and handle radio link failures by separately tracking retransmissions for multiple UL carriers, providing specific failure information for each carrier, and triggering common RLF indications based on shared retransmissions, allowing for efficient carrier switching and recovery procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate monitoring of retransmissions is performed for each UL carrier, then measurement precision of radio link failure detection is improved, but device complexity increases
Solution Approach 1:
The patent segments the retransmission monitoring process by carrier, maintaining separate counters and monitoring mechanisms for each UL carrier (NR UL carrier and SUL carrier). This segmentation enables precise identification of which carrier experiences RLF, improving measurement precision while managing complexity through structured separation of monitoring functions.
Solution Approach 2:
The patent implements dynamic monitoring where the UE can switch between different monitoring modes (separate carrier monitoring vs. common monitoring) based on configuration. The system adapts its monitoring behavior dynamically, allowing flexibility in balancing between measurement precision and device complexity based on network conditions and UE capability.
2Device complexity
If common RLF indication is triggered based on shared retransmissions, then device complexity is reduced, but measurement precision of carrier-specific failure detection deteriorates
Solution Approach 1:
The patent allows dynamic configuration of monitoring granularity. The network can configure the UE to use common monitoring (simplifying device complexity) or separate carrier monitoring (improving measurement precision) based on operational requirements. This dynamic adaptability resolves the contradiction by allowing the system to choose the appropriate level of detail contextually.
Solution Approach 2:
The patent enables changing the monitoring parameter (granularity level) based on configuration. By allowing parameter changes in the monitoring approach - switching between common and separate carrier monitoring - the system can optimize the balance between device complexity and measurement precision according to network conditions and operational needs.
3Adaptability or versatility
If frequent carrier switching is performed to handle varying radio conditions, then adaptability to changing network conditions is improved, but loss of time increases due to frequent reconfiguration
Solution Approach 1:
The patent implements feedback mechanisms where the UE reports radio link status and retransmission success/failure to the network. This feedback enables intelligent carrier switching decisions, allowing the system to switch carriers only when necessary based on actual radio conditions, thereby improving adaptability while minimizing unnecessary switching and associated time losses.
Solution Approach 2:
The patent allows preliminary configuration and preparation of backup carriers. By having the network pre-configure alternative carriers and maintaining readiness to switch, the system can perform faster carrier switching when needed, reducing the time loss associated with reconfiguration while maintaining high adaptability to changing radio conditions.
Data Source
AI summary
The invention refers to a method in a user equipment, UE (200), for handling radio link failures, wherein the UE is connected to a radio communication network by means of a plurality of uplink, UL, carriers (220, 230), comprising: monitoring (S41) retransmissions of radio link control, RLC, data packets for at least two of the plurality of UL carriers, determining (S42) a failure of RLC data packet transmissions with respect to one of the UL carriers, and providing (S43) an information indicative of the failure and said UL carrier; the invention further refers to a method in the UE (200), for handling radio link failures, wherein the UE is connected to a radio communication network by means of a plurality of UL carriers (210, 220, 230), comprising performing (S61) retransmissions of a certain RLC data packet on at least two of the plurality of UL carriers, monitoring (S62) retransmissions of a radio link control, RLC, data packet commonly for bthe at least two UL carriers, and providing (S63) an information indicative of a common RLF; the invention further refers to corresponding methods in a base station (100), corresponding UEs (200) and base stations (100), a corresponding communication system and a corresponding method in the communication system.