SRS Carrier Switching for Multi-Carrier Uplink Reliability
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Solution Overview
Problem
In multi-carrier communication systems, especially in LTE, the reliability of SRS transmission is compromised due to insufficient uplink capability, leading to limited simultaneous transmission of uplink carriers, which affects the determination of downlink channel statuses in TDD carriers.
Innovation Solution
The proposed solution involves determining and switching between specific uplink carriers, including SUL and non-SUL carriers, for SRS carrier switching, based on configuration information and DCI, to ensure reliable SRS transmission by selecting the appropriate carrier for SRS transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a terminal supports simultaneous transmission of only M uplink carriers when N component carriers are configured, then the uplink resource utilization is limited, but the reliability of SRS transmission is compromised
Solution Approach 1:
The patent introduces dynamic carrier switching for SRS transmission. The terminal can switch between different uplink carriers (first uplink carrier and second uplink carrier) based on configuration information and downlink control information. This dynamic switching allows the terminal to utilize multiple uplink carriers for different purposes: one carrier for data transmission and another for SRS transmission, thereby improving both uplink resource utilization and SRS transmission reliability simultaneously
Solution Approach 2:
The patent changes the operational parameters of the terminal by introducing carrier switching capability. The terminal is configured with multiple uplink carriers and can dynamically change which carrier is used for SRS transmission based on downlink control information. This parameter change enables the terminal to transmit SRS on a different carrier than the one used for data transmission, resolving the contradiction between resource utilization and transmission reliability
2Measurement precision
If the terminal determines downlink channel status in TDD carriers based on limited simultaneous uplink carrier transmission, then the measurement capability is insufficient, but the carrier switching complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the network side sends downlink control information to the terminal, indicating which uplink carrier should be used for SRS transmission. The terminal uses this feedback information to switch carriers accordingly. This feedback mechanism simplifies the terminal's decision-making process and reduces switching complexity while ensuring accurate downlink channel status determination through reliable SRS transmission
Solution Approach 2:
The patent introduces downlink control information as an intermediary that mediates between the network's carrier configuration and the terminal's transmission actions. This intermediary carries the carrier indication information that guides the terminal's carrier switching behavior, thereby reducing the complexity of direct carrier switching while maintaining measurement precision for downlink channel status determination
Data Source
AI summary
This application discloses a carrier switching solution for multi-carrier communication. A network device sends configuration information to a terminal. The configuration information includes first uplink carrier information and second uplink carrier information. The first uplink carrier information indicates that a first uplink carrier is an SRS switching-from uplink carrier. The second uplink carrier information indicates that a second uplink carrier is an SRS switching-to uplink carrier. At least one of the first uplink carrier and the second uplink carrier belongs to a cell including a supplementary uplink (SUL) carrier. The terminal may determine the SRS switching-from uplink carrier and the SRS switching-to uplink carrier in a plurality of configured uplink carriers based on the configuration information.