Uplink Control Signaling for Carrier Aggregation Scheduling Errors
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Solution Overview
Problem
Modern mobile communication networks face challenges in managing resource use due to the need to support legacy devices with limited bandwidth capabilities, leading to increased complexity and overhead in configuring and managing networks that utilize expanded carrier spectrums through carrier aggregation, especially when transmission errors occur.
Innovation Solution
A method for wireless communication terminals that involves receiving downlink control messages, determining whether they contain scheduling information for primary or secondary carriers, and selecting an appropriate format for uplink control messages based on this information to reduce overhead and adapt to transmission errors, including determining transmission power levels for uplink control messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If carrier aggregation is used to support expanded carrier spectrums while maintaining backwards compatibility, then the network can support both legacy and current-generation terminals, but the configuration and management complexity of the network significantly increases
Solution Approach 1:
The patent segments the expanded carrier spectrum into multiple separate component carriers (CCs). Each CC is configured independently with its own scheduling information, allowing legacy terminals to recognize and use only the CCs they support while current-generation terminals can aggregate multiple CCs. This segmentation approach enables backwards compatibility without requiring complex reconfiguration of the entire network, as each CC can be managed independently.
Solution Approach 2:
The patent creates a universal scheduling mechanism that serves multiple functions: it can schedule legacy terminals on single CCs, current-generation terminals on aggregated CCs, and handle retransmissions across different CCs. The scheduling information format is designed to be universally applicable to all terminal types, reducing the need for separate configuration schemes and thereby managing complexity while supporting diverse capabilities.
2Loss of information
If the network notifies a mobile device over a non-ideal radio channel that the device has been scheduled to use a particular component carrier, then scheduling information can be transmitted, but the mobile device may not successfully receive the notification and it becomes difficult or impossible for the device to determine what scheduling information to expect
Solution Approach 1:
The patent implements a feedback mechanism where the mobile device reports received scheduling information back to the network. This feedback loop allows the network to verify successful delivery of scheduling notifications and identify any missing information. The device can indicate which CCs it successfully received scheduling information for, enabling the network to retransmit or adjust scheduling for any missed notifications, thereby resolving uncertainty even over non-ideal radio channels.
Solution Approach 2:
The patent uses preliminary scheduling information transmission before actual data transmission on component carriers. By notifying the device in advance of scheduled CC usage through downlink control messages, the device can prepare its reception and transmission parameters beforehand. This preliminary action reduces the difficulty of detecting and measuring scheduling information during actual data transmission, as the device already knows what to expect.
3Loss of information
If the device reports on all the scheduling information it receives to permit the network to determine by deduction what scheduling information the device did not receive, then the network can identify missing information, but a significant amount of the network's transmission resource would be used up unnecessarily on such signaling when the mobile device successfully receives all the scheduling information
Solution Approach 1:
The patent implements a selective reporting mechanism where the device reports only the necessary subset of scheduling information rather than all received information. The device can indicate which specific CCs it successfully received scheduling information for, allowing the network to identify missing information only where needed. This partial action approach maintains the network's ability to detect missing scheduling information while significantly reducing unnecessary signaling overhead compared to reporting all scheduling information universally.
Data Source
AI summary
A method of operating a wireless communication terminal includes receiving one or more downlink control messages that each contain scheduling information scheduling the wireless terminal to receive a downlink transmission on either a primary carrier or a secondary carrier. The method also includes determining, for each of the downlink control messages, whether that message includes scheduling information for the primary carrier or for a secondary carrier. Additionally, the method includes selecting a format for an uplink control message based on whether any of the downlink control messages includes scheduling information for a secondary carrier, generating an uplink control message based on the selected format, and transmitting the uplink control message to the base station.