LTE Downlink Scheduling for DME Interference Mitigation

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Solution Overview

Problem

The LTE system experiences significant interference from Distance Measuring Equipment (DME) devices, leading to low Carrier to Interference plus Noise Ratio (CINR) in downlink channels, resulting in repeated subframe retransmissions and wastage of wireless resources due to invalid data validation and modulation scheme failures.

Innovation Solution

Dynamic scheduling of LTE data is implemented based on symbol level DME interference results and PDSCH scheduling situations, where scheduling messages (DTX, ACK, or NACK) are sent to adaptively manage subframe interference, allowing the LTE UE and eNB to adjust Modulation and Coding Scheme (MCS) values and HARQ processes accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If LTE downlink operates in the same frequency range as DME equipment, then the LTE system can provide air-to-ground communication services, but the Carrier to Interference plus Noise Ratio (CINR) becomes very low due to DME interference

Engineering Contradiction:

Improveair-to-ground communication capabilityVSAvoiddownlink channel quality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements dynamic scheduling that adapts to DME interference conditions by adjusting resource allocation based on detected interference levels. The system dynamically modifies transmission parameters including MCS selection and resource block allocation according to real-time channel conditions, enabling the LTE system to maintain reliable communication despite varying DME interference levels.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes key transmission parameters including Modulation and Coding Scheme (MCS) values, resource block allocation, and transmission power based on detected DME interference conditions. By adjusting these parameters dynamically, the system optimizes downlink performance in the presence of DME interference while maintaining air-to-ground communication capability.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If subframes are retransmitted multiple times due to DME interference, then data validation attempts are made, but wireless resources are wasted due to invalid retransmissions and CRC validation failures

Engineering Contradiction:

Improvedata validation success rateVSAvoidwireless resource waste

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent performs preliminary detection of DME interference conditions before attempting data transmission or retransmission. By detecting interference patterns in advance, the system can preemptively adjust scheduling decisions, avoiding unnecessary retransmissions that would waste wireless resources. This preliminary action enables the system to identify when retransmission is likely to fail due to persistent DME interference.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where the system monitors CRC validation results and retransmission outcomes to detect patterns of DME interference. Based on this feedback, the scheduler adjusts future transmission decisions, identifying when continuous retransmissions are occurring and modifying scheduling to prevent further resource waste from invalid retransmissions.

Inventive Principle:

Principle #23Feedback

3Productivity

If repeated retransmissions occur due to low CINR, then more transmission attempts are made, but the Modulation and Coding Scheme (MCS) values are negatively affected and downstream traffic decreases

Engineering Contradiction:

Improvedownstream traffic throughputVSAvoidMCS scheduling accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements dynamic MCS selection that adapts to DME interference conditions. Rather than using fixed MCS values, the system dynamically adjusts modulation and coding parameters based on real-time channel quality indicators and detected interference levels. This dynamic adaptation prevents the degradation of MCS values that would occur with repeated failed retransmissions, maintaining higher downstream traffic throughput.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent performs preliminary assessment of DME interference conditions before scheduling transmissions, enabling proactive selection of appropriate MCS values. By evaluating channel conditions in advance and selecting suitable MCS parameters beforehand, the system avoids the need for multiple retransmissions that would otherwise degrade scheduling accuracy and reduce downstream traffic performance.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP3065440B1Method, device and storage medium for increasing distance measuring equipment interference-prevention capabilities in LTE systems

Publication Date: 2023.12.20 ZTE CORP

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AI summary

A method for improving a Distance Measure Equipment (DME) interference resisting capability of a Long Term Evolution (LTE) system are described in the present disclosure; at an LTE User Equipment (UE) side, the method includes that: a symbol level DME interference result is obtained, and a scheduling message is sent according to the obtained symbol level DME interference result or according to the obtained symbol level DME interference result and a Physical Downlink Shared Channel (PDSCH) scheduling situation of a current subframe; at an LTE evolved Node B (eNB) side, the method includes that: the received scheduling message is detected, and a subframe is scheduled according to the received scheduling message. The present disclosure also discloses a UE, an eNB and two computer storage media for improving the DME interference resisting capability of the LTE system.