Downlink Synchronization Sequence Terminal Type Indication
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Solution Overview
Problem
In LTE networks, low-cost MTC UEs may fail to decode system information and paging messages when moving to legacy eNBs not supporting new UE categories, leading to unpredictable UE behaviors, and there is a need for terminals to quickly identify if a current cell supports their specific narrowband capabilities for improved power saving and compatibility.
Innovation Solution
A method where a base station carries preset indication information, such as a synchronization sequence or indicator bits, in downlink signals to notify terminals about the supported terminal types, allowing them to determine the coverage enhancement level and access the cell accordingly, using pre-configured correspondences between these indicators and coverage capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If legacy eNBs do not support new UE categories, then existing LTE network compatibility is maintained, but narrowband terminals cannot successfully decode system information and paging messages
Solution Approach 1:
The system segments the downlink signal by inserting synchronization sequences at specific positions within the downlink frame structure. These synchronization sequences are divided into different types (first type and second type) that can indicate different terminal type support scenarios, allowing legacy eNBs to selectively support narrowband terminals without requiring full system redesign.
Solution Approach 2:
Synchronization sequences serve as an intermediary mechanism between legacy eNBs and narrowband terminals. The eNB inserts appropriate synchronization sequences as intermediaries to convey terminal type support information, enabling narrowband terminals to identify and camp on suitable cells without requiring the eNB to have full narrowband terminal support capabilities.
2Measurement precision
If narrowband terminals continuously monitor downlink signals to identify cell support, then terminal type identification accuracy is improved, but power consumption increases
Solution Approach 1:
The system uses periodic synchronization sequences inserted at regular intervals in the downlink signal. Narrowband terminals can detect these periodic synchronization sequences to identify cell support, reducing the need for continuous monitoring and thereby lowering power consumption while maintaining identification accuracy.
Solution Approach 2:
Narrowband terminals perform self-identification by detecting the presence and type of synchronization sequences in downlink signals. The terminal autonomously determines whether the current cell supports narrowband terminals based on the detected synchronization sequence characteristics, eliminating the need for continuous active monitoring and reducing power consumption.
3Adaptability or versatility
If synchronization sequences are inserted in downlink signals to indicate terminal type support, then narrowband terminal access capability is improved, but downlink signal complexity increases
Solution Approach 1:
The synchronization sequences serve multiple functions: they provide synchronization information for terminal acquisition, indicate terminal type support capabilities, and enable cell identification. By making the synchronization sequences multi-functional, the system avoids adding separate dedicated indication signals, thereby limiting the increase in downlink signal processing complexity while improving multi-terminal type support.
Solution Approach 2:
The system changes parameters of existing synchronization sequences (such as sequence type, position, or pattern) to convey terminal type support information. Instead of adding new complex signal structures, the eNB modifies parameters of conventional synchronization sequences to indicate support for narrowband terminals, thereby limiting the increase in signal processing complexity.
Data Source
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AI summary
This application provides a method, a device, and a system for notifying a terminal type supported by a current cell, so that a UE can identify the terminal type supported by the current cell as soon as possible. The method includes: carrying preset indication information in a downlink signal, where the indication information is used to indicate the terminal type supported by the current cell, the preset indication information is agreed upon by a network side and a terminal in advance, and the indication information is a synchronization sequence or a first indicator bit used to indicate the supported terminal type; and sending the downlink signal to the terminal.