DMTC Configuration for Asynchronous SCells in Unlicensed LTE
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In LTE networks operating in unlicensed spectrum, asynchronous cells pose challenges for Discovery Signal Measurement Timing Configuration (DMTC), leading to inefficient measurement performance and increased power consumption due to the need to search for unsynchronized cells without knowing their presence.
Innovation Solution
The DMTC configuration is tailored for Secondary Cells (SCells) and asynchronous cells, providing specific timing configurations within System Information Blocks (SIBs) and measurement objects to improve measurement performance and reduce unnecessary searches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the UE performs comprehensive searches for asynchronous cells without prior indication, then measurement coverage is improved, but power consumption increases
Solution Approach 1:
The network performs preliminary action by providing asynchronous cell indications to the UE before the UE performs measurements. This allows the UE to have advance knowledge of which cells to measure, eliminating the need for comprehensive blind searches and thereby reducing power consumption while maintaining measurement coverage.
Solution Approach 2:
The asynchronous cell indication acts as an intermediary information element that mediates between the network's knowledge of cell configurations and the UE's measurement capabilities. This intermediary provides the UE with targeted measurement information, resolving the contradiction between comprehensive measurement coverage and power-efficient operation.
2Measurement precision
If the UE performs comprehensive searches for asynchronous cells, then measurement completeness is improved, but measurement time increases
Solution Approach 1:
The network provides asynchronous cell indications in advance, enabling the UE to perform measurements only on indicated cells rather than conducting exhaustive searches. This preliminary information provision significantly reduces measurement time while ensuring measurement completeness for all relevant cells.
Solution Approach 2:
The measurement approach transitions from a static comprehensive search strategy to a dynamic targeted measurement strategy. The UE dynamically adjusts its measurement behavior based on the received asynchronous cell indications, measuring only those cells that are indicated rather than all possible cells, thereby reducing measurement time while maintaining completeness.
3Device complexity
If a single DMTC configuration is used for all cells, then system complexity is reduced, but measurement performance on SCells deteriorates
Solution Approach 1:
The DMTC configuration is segmented into cell-specific configurations rather than using a single unified configuration. Each SCell can have its own DMTC parameters tailored to its specific characteristics, such as discovery signal periodicity and timing. This segmentation improves measurement performance on SCells while maintaining manageable system complexity through standardized configuration structures.
Solution Approach 2:
The measurement configuration applies local quality by providing differentiated DMTC parameters for different cells based on their specific requirements. SCells receive customized DMTC configurations that match their local characteristics, such as their discovery signal timing and periodicity, rather than applying a one-size-fits-all configuration. This local optimization improves measurement performance while the overall system maintains structured complexity.
Data Source
AI summary
Systems and methods relating to Discovery Signal Measurement Timing Configuration (DMTC) are disclosed. In some embodiments, a method of operating a radio access node in a cellular communications network having a primary cell and a secondary cell, comprises sending, to a wireless device, a DMTC for one of a group consisting of: (a) the secondary cell configured for the wireless device such that the DMTC is a specific DMTC for the secondary cell; and (b) the primary cell and additional cells that are configurable as secondary cells such that the DMTC applies to both the primary cell and the additional cells when configured as secondary cells. Related radio access nodes and wireless devices are also disclosed.