LTE In-Device Coexistence Interference Mitigation via Dynamic MAC CE Indicators
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Solution Overview
Problem
Current LTE RRM designs do not effectively address in-device coexistence interference between multiple radios in a user equipment, leading to significant degradation, long response times, and ping-pong effects due to overlapping or adjacent radio spectrums.
Innovation Solution
Implementing UE and eNB-centric solutions that identify and mitigate in-device coexistence interference through UE ID allocation, cell selection/reselection in non-ISM frequency bands, capability negotiation, and dynamic reporting of interference measurements to manage radio resource allocation and handovers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple radio transceivers operate simultaneously in overlapping or adjacent frequency bands, then wireless communication coverage and service capability are improved, but in-device coexistence interference significantly degrades reception quality
Solution Approach 1:
The patent segments the radio frequency resources by introducing separate indicator fields in MAC CE for different frequency bands (first frequency band indicator and second frequency band indicator). This allows independent control and management of coexistence interference in different frequency segments, enabling the system to selectively mitigate interference in affected bands while maintaining operation in non-interfering bands.
Solution Approach 2:
The patent changes the parameter representation by using bit field indicators to dynamically indicate which frequency bands are affected by coexistence interference. The network can adjust the interference mitigation strategy by modifying these indicator parameters, enabling flexible adaptation to different interference scenarios without changing the overall system architecture.
2Reliability
If radio resource management uses conventional RLF declaration and handover mechanisms, then mobility management is maintained, but response time increases to one second or longer due to late interference detection
Solution Approach 1:
The patent implements preliminary action by introducing early warning indicators for coexistence interference before radio link failure occurs. The MAC CE includes indicators that notify the network of impending interference conditions, allowing proactive handover or resource reallocation decisions to be made before the connection degrades to the point of conventional RLF detection, thus reducing response time significantly.
Solution Approach 2:
The patent establishes a feedback mechanism where the UE reports coexistence interference status to the network via MAC CE messages. This continuous feedback loop enables the network to monitor interference conditions in real-time and adjust resource allocation or initiate handover procedures promptly, improving response time compared to passive RLF-based mechanisms.
3Object-affected harmful factors
If radio resource management allows frequent handovers to mitigate interference, then interference avoidance is improved, but ping-pong effects occur causing instability
Solution Approach 1:
The patent applies local quality by providing differentiated handover control for different frequency bands through separate indicator fields. The network can apply interference mitigation strategies selectively to specific bands affected by coexistence interference while maintaining normal handover behavior in non-affected bands, preventing unnecessary handovers and reducing ping-pong effects.
Solution Approach 2:
The patent introduces dynamic control through configurable handover parameters and hysteresis mechanisms that adapt to the reported interference conditions. The network can dynamically adjust handover thresholds and parameters based on the MAC CE interference indicators, enabling flexible response that avoids both excessive handovers and insufficient interference mitigation.
4Adaptability or versatility
If existing LTE RRM designs are used without modification, then backward compatibility is maintained, but in-device coexistence interference mitigation capability is insufficient
Solution Approach 1:
The patent achieves universality by extending existing LTE RRM mechanisms to serve dual purposes: maintaining backward compatibility with conventional systems while simultaneously providing enhanced coexistence interference mitigation. The MAC CE extensions and indicator fields can be interpreted by both legacy systems (ignoring the new fields) and enhanced systems (utilizing the new fields for interference management), allowing one mechanism to serve multiple functions.
Solution Approach 2:
The patent uses MAC CE messages as an intermediary layer that carries coexistence interference indicators without disrupting existing RRM protocols. This intermediary mechanism bridges the gap between legacy LTE RRM designs and new interference mitigation requirements, allowing enhanced functionality to be added while maintaining compatibility with existing network infrastructure and protocols.
Data Source
AI summary
Various methods for wireless communication in a device with co-existed/co-located radios are provided. Multiple communication radio transceivers are co-existed/co-located in a user equipment (UE) having in-device coexistence (IDC) capability, which may result in IDC interference. For example, the UE is equipped with both LTE radio and some ISM band applications such as WiFi and Bluetooth modules. In a first method, the network identifies IDC capability by UE identification (e.g., UE ID). In a second method, the UE intentionally performs cell selection or reselection to cells in non-ISM frequency bands. In a third method, the UE signals the existence of ISM band applications via capability negotiation. In a fourth method, the UE signals the activation of ISM band applications by signaling messages (e.g., RRC message or MAC CE). Under the various methods, the UE and its serving eNB can apply FDM or TDM solutions to mitigate the IDC interference.