LTE Unlicensed Spectrum Control Plane Measurement Segmentation
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Solution Overview
Problem
Wireless communication devices operating in unlicensed spectrum face interference and delayed transmissions due to 'listen-before-talk' approaches, leading to issues with radio resource management and radio link failure detection.
Innovation Solution
Performing control plane measurements in wireless devices to identify and differentiate between opportunistic and guaranteed transmissions across multiple sub-frames, determining measurement values, and using timers for uplink transmissions to detect radio link failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If clear channel assessment (CCA) procedures are performed to detect interference in unlicensed spectrum, then interference mitigation is improved, but transmission delays increase and transmission reliability deteriorates
Solution Approach 1:
The patent segments transmissions into two distinct types: guaranteed transmissions (which occur without CCA procedures) and opportunistic transmissions (which require CCA procedures). This segmentation allows the system to ensure that critical control plane signals and reference signals are transmitted reliably without delay, while data transmissions can utilize CCA-based interference mitigation when appropriate. The segmentation resolves the contradiction by applying different transmission strategies to different types of traffic.
Solution Approach 2:
The patent establishes predetermined rules and configurations for guaranteed transmissions before actual transmission occurs. The network configures the UE with specific parameters indicating which subframes will contain guaranteed transmissions, allowing the UE to prepare for reliable reception without performing CCA procedures at transmission time. This preliminary configuration ensures that critical transmissions occur on time while still maintaining interference awareness.
2Object-affected harmful factors
If clear channel assessment (CCA) procedures are performed to detect interference, then interference mitigation is improved, but transmission reliability deteriorates due to missing reference signals
Solution Approach 1:
The patent segments transmissions into guaranteed transmissions (without CCA) and opportunistic transmissions (with CCA). Guaranteed transmissions ensure that critical control plane signals and reference signals are transmitted reliably, providing a stable foundation for UE measurements and radio link monitoring. This segmentation ensures that the most reliability-critical transmissions are protected from CCA-induced delays and failures.
Solution Approach 2:
The patent introduces a configuration mechanism as an intermediary between the network and UE. The network provides configuration information to the UE that identifies which subframes will contain guaranteed transmissions. This intermediary configuration layer allows the UE to distinguish between guaranteed and opportunistic transmissions, enabling reliable measurement of control plane signals while still allowing opportunistic data transmissions to benefit from CCA-based interference mitigation.
3Object-affected harmful factors
If listen-before-talk (LBT) approaches are used in unlicensed spectrum, then interference detection is improved, but radio resource management and radio link monitoring become more difficult
Solution Approach 1:
The patent introduces configuration information as an intermediary that simplifies radio resource management. The network provides the UE with configuration parameters that clearly identify which subframes contain guaranteed transmissions versus opportunistic transmissions. This intermediary configuration layer reduces the complexity of radio resource management by providing explicit guidance to the UE, eliminating the need for complex autonomous decisions about transmission types.
Solution Approach 2:
The patent enables the UE to autonomously identify and measure guaranteed transmissions using the provided configuration information. Once configured, the UE can independently determine which subframes contain guaranteed transmissions and perform appropriate measurements without requiring continuous network control or complex coordination. This self-service capability reduces radio resource management complexity while maintaining interference detection benefits.
Data Source
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AI summary
A method for control plane measurements in a wireless device is described, the method comprising measuring, across multiple sub-frames received over an unlicensed spectrum, received cell-specific reference signals, CRS, from a cell to obtain CRS measurements, identifying one or both of a first subset of the CRS measurements associated with a first subset of the sub-frames including opportunistic transmissions and a second subset of the CRS measurements associated with a second subset of the sub-frames including guaranteed transmissions, computing one or both of a first signal to interference plus noise ratio, SINR, value for the first subset of the CRS measurements and a second SINR value for the second subset of the CRS measurements, and monitoring a radio link condition of the wireless device based at least in part on the first SINR value computed for the first subset of CRS measurements or the second SINR value computed for the second subset of CRS measurements. Also, a corresponding apparatus and a corresponding computer-readable medium are described.