Adaptive Frequency Separation for Narrowband MTC Measurement Patterns

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Solution Overview

Problem

Narrowband Machine Type Communication (MTC) user equipment (UE) faces challenges with self-interference due to insufficient transmit-receive frequency separation, leading to degraded error rate performance and reduced coverage, especially when operating at narrow bandwidths near the edge of the system bandwidth with reduced duplex filtering capabilities.

Innovation Solution

A measurement pattern is implemented with at least two time periods, where the first time period involves a specific set of physical channels located at the center of the system bandwidth for improved performance, and the second time period allows for measurements or data transmission using channels at any location within the bandwidth, ensuring sufficient radio resources for uplink and downlink operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If narrowband MTC UE operates with reduced transmit-receive frequency separation to enable flexible resource allocation, then frequency resource utilization improves, but self-interference increases causing degraded error rate performance

Engineering Contradiction:

Improvefrequency resource allocation flexibilityVSAvoiderror rate performance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the operation into two distinct time periods: a first time period where the UE operates with narrowband channels at specific frequency locations optimized for measurement, and a second time period for normal data transmission. This temporal segmentation allows the UE to achieve both flexible resource allocation and reliable measurement performance by switching between different operational modes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic frequency tuning where the UE adjusts its operating frequency between the first and second time periods. During the first time period, the UE tunes to frequency locations that provide sufficient transmit-receive separation for accurate measurements, while during the second time period, it operates with flexible frequency allocation for data transmission. This dynamic adaptation resolves the contradiction between flexibility and reliability.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If narrowband MTC UE uses channels at any frequency location for data transmission, then resource allocation flexibility improves, but measurement accuracy deteriorates due to insufficient transmit-receive frequency separation

Engineering Contradiction:

Improvechannel location flexibilityVSAvoidmeasurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent divides the operational timeline into segmented periods with different frequency allocation strategies. The first time period is dedicated to measurements with constrained frequency locations that ensure adequate transmit-receive separation, while the second time period allows flexible channel allocation for data transmission. This segmentation ensures measurement accuracy is not compromised by flexible resource allocation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements periodic measurement opportunities within the time structure, where the UE periodically switches to the first time period mode to perform measurements at optimized frequency locations. This periodic action ensures that measurement precision is maintained at regular intervals despite the flexible channel allocation occurring during the second time period.

Inventive Principle:

Principle #19Periodic action

3Reliability

If MTC UE performs measurements on frequencies with large path loss, then coverage extension improves, but signal reception difficulty increases

Engineering Contradiction:

Improvecoverage capabilityVSAvoidsignal reception difficulty

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent performs measurements during the first time period before data transmission begins in the second time period. By conducting measurements preliminarily at frequency locations with optimized transmit-receive separation, the UE can assess channel conditions and plan subsequent data transmission strategies, thereby extending coverage while managing reception difficulty.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The measurement results obtained during the first time period provide feedback that informs resource allocation and transmission parameter selection during the second time period. This feedback mechanism allows the system to adapt to large path loss conditions by adjusting transmission parameters based on actual measured channel quality, thereby extending effective coverage.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9918243B2Measurement procedure under adaptive frequency separation

Publication Date: 2018.03.13 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

According to some embodiments, a method in a wireless device comprises determining the wireless device is capable of narrow bandwidth operation. The wireless device obtains a parameter associated with a measurement pattern The measurement pattern comprises: a first time period and a second time period; a first type of radio measurements to be performed during the first time period on radio signals transmitted in a first set of physical resource channels; and a second type of radio measurements to be performed during the second time period on radio signals transmitted in a second set of physical resource channels. The wireless device determines a measurement pattern using the obtained parameter, and performs radio measurements of the first type during the first time period.