Inter-RAT Handover Parameter Coordination for RLF Reduction
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Solution Overview
Problem
Existing systems face challenges in optimizing handover between different radio access technologies (RATs) to reduce radio link failures (RLFs) while avoiding excessive back-and-forth handovers, leading to inefficient mobility management and coverage issues.
Innovation Solution
The method involves coordinating handover parameters, such as adjusting handover thresholds, between different radio access technologies (RATs) through a controller that determines and transmits handover parameter values, including quality of service (QoS) and user equipment (UE) capability parameters, to optimize mobility settings and reduce RLFs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If handover thresholds are adjusted to reduce radio link failures, then mobility robustness is improved, but excessive back-and-forth handovers may occur
Solution Approach 1:
The system implements feedback mechanisms where controllers exchange handover parameter values and QoS/UE capability parameters between different RATs. This feedback loop enables dynamic adjustment of handover thresholds based on actual network conditions, allowing the system to reduce RLFs while preventing excessive handovers through continuous monitoring and adaptation.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting handover threshold values based on QoS requirements and UE capabilities. Different handover parameter values are determined for different QoS classes and UE types, enabling optimized handover decisions that balance mobility robustness with handover efficiency across multiple parameter dimensions.
2Reliability
If handover parameters are optimized for one RAT, then performance in that RAT is improved, but coordination with other RATs may be insufficient
Solution Approach 1:
The system achieves universality by creating a multi-functional handover parameter determination mechanism that simultaneously serves multiple RATs (e.g., UTRAN and e-UTRAN). The controllers exchange and coordinate handover parameters across different RAT boundaries, enabling a single coordinated system to optimize handover performance universally across heterogeneous radio access technologies while adapting to specific RAT characteristics.
Data Source
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Figure 3A~3B
AI summary
A system, method, and apparatus are presented for coordinating handover. A first controller (105) that is associated with a first RAN cell determines (702) a first handover parameter value that is for use in determining whether to cause handover from the first RAN cell to a second RAN cell having a different RAT. The first controller (105) transmits (702), to a second controller (112) associated with the second RAN cell, information relating to the first handover parameter value. The first controller further transmits (704), to the second controller, a value of a QoS parameter or a UE capability parameter associated with the information. The first controller receives (704), from the second controller, an indication of whether the second controller has adjusted a second handover parameter value based on the transmitted information, where the second handover parameter value is for use in determining whether to cause handover from the second RAN cell to the first RAN cell.