Uplink Power Control in Carrier Aggregation via Subframe Overlap
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Solution Overview
Problem
In wireless communication systems with carrier aggregation, the inaccurate uplink power control due to varying transmit times of uplink signals through different cells degrades the quality of uplink data transmission.
Innovation Solution
A method for determining uplink transmission power by a user equipment, which involves determining the overlap between uplink channels of cells in current and adjacent subframes to accurately calculate the transmission power of the physical uplink shared channel (PUSCH) across cells in carrier aggregation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If uplink power control is performed based on prior art methods, then the transmission power can be determined, but the accuracy of power control deteriorates due to varying transmit times through different cells
Solution Approach 1:
The base station performs preliminary actions by determining uplink transmit times for multiple cells and notifying the user equipment of these timings before uplink transmission occurs. This preliminary timing synchronization enables accurate power control across carrier aggregation cells by establishing a reference framework in advance, resolving the accuracy issue without adding complex real-time adjustment mechanisms.
Solution Approach 2:
The power control mechanism is segmented into distinct functional components: a determining unit that calculates transmit times for different cells, a notification unit that communicates these timings to the user equipment, and a power control unit that uses the timing information. This segmentation allows each component to be optimized independently while maintaining overall system accuracy.
2Adaptability or versatility
If uplink signals are transmitted through different cells with different paths, then carrier aggregation functionality is achieved, but the uplink transmit time varies causing power control inaccuracy
Solution Approach 1:
The invention applies local quality by determining specific uplink transmit times for each individual cell within the carrier aggregation group, rather than using a uniform timing approach. Each cell's transmit time is optimized for its specific path characteristics, allowing the system to maintain both the versatility of multi-cell aggregation and the precision of path-specific timing control.
Solution Approach 2:
The base station performs preliminary determination of uplink transmit times for all carrier aggregation cells before uplink transmission. By establishing these timings in advance and notifying the user equipment, the system resolves the timing variations caused by different transmission paths without requiring complex real-time adjustments during actual data transmission.
3Reliability
If the base station adjusts uplink transmit time to ensure synchronous arrival, then signal synchronization is improved, but the complexity of timing management increases across multiple cells
Solution Approach 1:
The base station acts as an intermediary that centralizes the timing management function. It determines the uplink transmit times for all carrier aggregation cells, communicates these timings to the user equipment through notification messages, and thereby coordinates synchronous arrival without requiring complex distributed timing management at the user equipment side.
Solution Approach 2:
The base station performs preliminary determination and notification of uplink transmit times for all carrier aggregation cells before uplink transmission occurs. This preliminary timing establishment simplifies the overall system by centralizing the complexity in the base station's control plane, while the user equipment merely follows the predetermined timing instructions during actual transmission.
Data Source
Figure 1~2
AI summary
The present invention provides a method for determining an uplink transmission power and a user equipment. In the present invention, a user equipment determines an overlap between an uplink channel of a cell in a current sub frame and an uplink channel of another cell in an adjacent sub frame, the cell being carrier aggregation with the another cell, so that the user equipment can determine transmission power of a PUSCH of the cell in the current subframe and the another cell in the current subframe, the another cell being carrier aggregation with the cell. As a result, the problem that the uplink power control performed by the user equipment according to the prior art is not accurate is solved and thus the uplink data transmitting quality is improved.