Unlicensed Carrier Discovery Signal Synchronization
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Solution Overview
Problem
Current wireless communication systems face challenges in maintaining synchronization and performing measurements on unlicensed frequency carriers due to interference from other systems operating in the same frequency range, as they cannot make periodic discovery signal transmissions without violating 'listen before talk' strategies.
Innovation Solution
The method involves determining measurement instances for discovery signal transmissions on unlicensed carriers using higher layer configuration messages and control channel messages, allowing for 'on-demand' detection and measurement by muting or moving the discovery signal transmissions to avoid interference, enabling synchronization and measurement reporting only when the channel is available.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If periodic discovery signal transmissions are made on unlicensed carriers, then synchronization and measurement accuracy are improved, but interference with other systems operating in the same frequency range increases
Solution Approach 1:
The patent implements dynamic discovery signal transmission by allowing the base station to adjust transmission timing and frequency based on channel conditions and interference levels. The system transitions from fixed periodic transmission to adaptive transmission where discovery signals are sent only when channel quality is favorable, resolving the contradiction between maintaining measurement accuracy and avoiding interference with other systems.
Solution Approach 2:
The patent changes key transmission parameters including timing offset, frequency selection, and power level based on channel state information and interference measurements. By dynamically adjusting these parameters, the system maintains synchronization accuracy while adapting to varying interference conditions from co-channel systems like Wi-Fi.
2Object-affected harmful factors
If discovery signal transmissions are muted or moved to avoid interference, then interference with other systems is reduced, but synchronization and measurement reliability deteriorate
Solution Approach 1:
The patent performs preliminary channel assessment and interference measurement before scheduling discovery signal transmissions. The base station evaluates channel conditions in advance and pre-selects optimal transmission opportunities, ensuring that discovery signals are transmitted only when reliability requirements can be met while minimizing interference to other systems.
Solution Approach 2:
The system implements feedback mechanisms where UEs report channel quality and synchronization status to the base station. This feedback loop allows the base station to adjust discovery signal transmission strategies in real-time, maintaining reliability by increasing transmission frequency when needed while reducing interference when channel conditions are poor.
3Productivity
If 'on-demand' discovery signal transmission is implemented, then channel utilization efficiency is improved, but system complexity increases
Solution Approach 1:
The patent enables the system to self-regulate discovery signal transmission based on embedded channel quality indicators and interference measurements. The base station autonomously determines transmission timing and parameters using pre-configured algorithms, reducing the need for complex centralized control while improving channel utilization through adaptive transmission.
Data Source
AI summary
Briefly, the present disclosure is directed to methods and apparatus that allow for the synchronization with, and measurement reporting of, unlicensed frequency carriers. A method and apparatus for synchronizing to an Scell operating on an unlicensed carrier determine, at a UE (108, 116), one or more measurement instances where a discovery signal may be transmitted, for example, by a base station (132), on the Scell from a higher layer configuration message. The method and apparatus may monitor a control channel for a control channel message and determine whether the discovery signal will be transmitted during one or more measurement instances on the Scell. The method and apparatus may detect the discovery signal transmission on the Scell during one or more of the measurement instances. The method and apparatus may also synchronize to and/or measure the Scell based on detected discovery signal transmissions.