Aided Synchronization for LTE Carrier Aggregation
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Solution Overview
Problem
In LTE Rel-10 networks, legacy terminals face challenges in efficiently utilizing wide carriers due to the need for monitoring multiple component carriers, leading to high power consumption and interference issues in heterogeneous network deployments, especially in scenarios where traditional synchronization signals are not available or are transmitted with reduced power.
Innovation Solution
The method involves transmitting synchronization signals on a primary carrier and providing information about secondary carriers to terminals, allowing them to perform aided synchronization using the primary carrier's timing and frequency, even if the secondary carriers do not transmit synchronization signals, thereby enabling efficient carrier aggregation and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If legacy terminals monitor multiple component carriers in LTE Rel-10 networks, then carrier aggregation capability is improved, but power consumption increases
Solution Approach 1:
The patent segments the carrier monitoring task by dividing carriers into two categories: primary carriers that require full monitoring, and secondary carriers that can use aided synchronization. This segmentation allows terminals to reduce monitoring effort on secondary carriers while maintaining carrier aggregation functionality, thereby reducing power consumption without sacrificing adaptability.
Solution Approach 2:
The patent implements preliminary action by having the network provide synchronization information about secondary carriers in advance through RRC signaling. This preliminary provision of timing and frequency synchronization data allows terminals to skip the power-consuming synchronization process for secondary carriers, reducing overall power consumption while maintaining carrier aggregation capability.
2Measurement precision
If synchronization signals are transmitted on all component carriers, then synchronization accuracy is improved, but interference increases in heterogeneous networks
Solution Approach 1:
The patent extracts the synchronization function from secondary carriers and concentrates it on primary carriers. By removing synchronization signals from secondary carriers and providing synchronization information through RRC signaling instead, the patent reduces the number of synchronization signals in heterogeneous networks, thereby reducing interference while maintaining synchronization accuracy through the extracted and centralized synchronization mechanism.
3Use of energy by moving object
If aided synchronization is implemented for secondary carriers, then power consumption is reduced, but device complexity increases
Solution Approach 1:
The patent introduces RRC signaling as an intermediary to transfer synchronization information from the network to the terminal. This intermediary mechanism simplifies the terminal's synchronization process for secondary carriers by providing ready-made synchronization data, reducing power consumption while the added complexity is managed at the network side rather than the terminal side.
Data Source
AI summary
A method of providing signal synchronization for a radio access network may include transmitting a first carrier including synchronization signals on a first frequency from the radio access network. Information relating the first carrier on the first frequency with a second carrier on a second frequency may be transmitted from the radio access network, with this information being intended to be used in synchronization by a wireless terminal upon addition of the second carrier. More particularly, the first and second frequencies may be different. A command to add the second carrier as a downlink for transmissions may be transmitted to the wireless terminal. Related network nodes and wireless terminals are also discussed.