Uplink Data Transmission Timing on Unlicensed Carriers
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Solution Overview
Problem
The inability to determine a precise moment for transmitting Uplink (UL) data on an unlicensed carrier in LTE systems, which affects data transmission efficiency.
Innovation Solution
Determining the start and end symbol locations of a Physical Uplink Shared Channel (PUSCH) transmission subframe through predefined settings or indication messages from a base station, allowing for successful Clear Channel Assessment (CCA) and efficient data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LBT is implemented before data transmission on unlicensed carrier, then channel access reliability is improved, but transmission timing determinability deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-defining multiple candidate start symbol locations (e.g., symbols 0, 1, 2, 3, 7, 10) for PUSCH transmission before actual data transmission occurs. The terminal performs LBT and selects the nearest candidate start symbol location, which resolves the timing determinability issue while maintaining LBT-based channel access reliability.
2Measurement precision
If PUSCH transmission starts from subframe symbol 0 on licensed carrier, then transmission timing is determined, but adaptability to unlicensed carrier LBT mechanism deteriorates
Solution Approach 1:
The patent applies dynamics by making the PUSCH start symbol location flexible and adaptive rather than fixed. Multiple candidate start symbol locations are defined, and the actual start position dynamically adjusts based on when LBT succeeds, allowing the system to adapt to unlicensed carrier conditions while maintaining timing determinability through predefined options.
Solution Approach 2:
The patent changes the parameter of start symbol location from a fixed value (symbol 0) to a set of discrete candidate values (symbols 0, 1, 2, 3, 7, 10). This parameter change enables the system to adapt to unlicensed carrier LBT mechanism while maintaining timing determinability through the predefined candidate set.
3Adaptability or versatility
If multiple candidate start symbol locations are defined, then adaptability to LBT timing is improved, but device complexity increases
Solution Approach 1:
The patent reduces device complexity by pre-defining the set of candidate start symbol locations in the standard specification. The terminal only needs to select from these predefined options based on LBT timing, rather than calculating or negotiating start positions dynamically, which simplifies the terminal's processing requirements.
Data Source
AI summary
A method and apparatus for sending and receiving uplink data, a terminal, and a base station are provided. The method comprises: determining, according to a self-defined instruction message or an instruction message received from a base station, a start symbol position or the start symbol position and an end symbol position for transmitting a subframe on a physical uplink shared channel (PUSCH) on an unlicensed carrier; and sending uplink data according to the start symbol position or according to the start symbol position and the end symbol position. By means of the embodiments of the present invention, the problem of failing to determine the time point of transmitting uplink data on an unlicensed carrier by a terminal is resolved, thereby achieving the effect of determining the time point of transmitting the uplink data on the unlicensed carrier by the terminal, and providing the effect of improving the data transmission efficiency.