UE Call Continuity via Early RLF Detection
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Solution Overview
Problem
Current wireless communication systems face challenges in maintaining call continuity due to delays in detecting Radio Link Failure (RLF) conditions, leading to increased call drop rates and degraded user experience, especially when UE transitions between different Radio Network Controllers (RNCs) or experiences suboptimal signal conditions.
Innovation Solution
The proposed solution involves a User Equipment (UE) with a call continuity management unit that detects specific events, such as prolonged acknowledgement delays, Directed Signaling Connection Re-establishment (DSCR) messages, or failed cell update attempts, triggering early RLF procedures and improvised cell selection to reduce call drops by re-establishing connections more quickly and avoiding unexpected releases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE waits for the RLF condition to be satisfied by conventional standards before triggering cell update, then the network can process RLF properly, but the call continuity is degraded due to considerable delay in detecting and declaring RLF
Solution Approach 1:
The patent applies preliminary action by having the UE trigger cell update procedure in advance when specific conditions (such as receiving DSCR message or failing to receive response from drift RNC) are met, before the conventional RLF declaration is completed. This early triggering of cell update prevents the call from being dropped due to RLF detection delay, thereby improving call continuity while reducing the time loss associated with waiting for RLF condition satisfaction.
2Reliability
If the UE triggers cell update to re-establish call after declaring RLF, then call continuity can be maintained, but the network may send RRC connection release causing call drop even though UE initiated cell update
Solution Approach 1:
The patent applies preliminary action by triggering cell update procedure before the network sends RRC connection release message. The UE monitors for specific conditions (DSCR message reception or failure to receive response from drift RNC) and initiates cell update in advance, ensuring that the cell update is completed before the network can send the release message, thus preventing call drop.
Solution Approach 2:
The patent applies feedback by having the UE monitor for specific network responses (DSCR messages or response from drift RNC) and adjust its behavior accordingly. When the UE receives DSCR message or fails to receive response within expected time, it triggers cell update based on this feedback information, ensuring that cell update is initiated only when necessary and before network release.
3Reliability
If the UE retries cell update until maximum attempts are exhausted when belonging to drift RNC, then call continuity might be maintained, but the ongoing call is dropped if unsuccessful
Solution Approach 1:
The patent applies preliminary action by triggering cell update procedure in advance when the UE detects that it belongs to a drift RNC or when specific conditions (DSCR message, failure to receive response) are met. This early triggering reduces the need for multiple retries and minimizes the time the call is in suspension, thereby improving call continuity while reducing the time loss associated with repeated cell update attempts.
Data Source
AI summary
Providing call continuity for an ongoing call of a User Equipment (UE) of a wireless communication by defining UE behavior specifying actions to be taken by the UE upon detection of occurrence of an event among a plurality of events that may occur during the ongoing call.