Wireless Terminal Transmit Power Control for Short TTI Latency
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Solution Overview
Problem
Current wireless communication systems face challenges in reducing packet data latency, particularly in next-generation mobile communication systems like new RAT and LTE, where efficient transmission power control is needed to support various transmission time intervals, processing times, and numerologies.
Innovation Solution
A method and apparatus for determining transmission power in a wireless communication system, which involves receiving a configuration for semi-persistent scheduling of short transmission time intervals, using transmit power control commands to control transmission power, and allowing for accumulated or absolute value-based operations per TTI length, with initial power control adjustment states set to 0 or predetermined values upon configuration or reconfiguration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transmission power control is implemented for semi-persistent scheduling in short TTI systems, then transmission efficiency and latency are improved, but system complexity increases due to multiple TTI lengths and power control modes
Solution Approach 1:
The patent segments the power control mechanism by introducing separate TPC commands for different TTI lengths (short TTI and long TTI). Each TTI type has its own power control state and accumulation process, allowing independent optimization without interfering with each other, thus managing complexity through structured division
Solution Approach 2:
The patent implements dynamic power control adjustment by allowing the UE to switch between accumulated value-based operation and absolute value-based operation modes. The system can dynamically select the appropriate power control mode based on current transmission requirements, enabling flexible adaptation to varying network conditions
2Measurement precision
If multiple TPC commands are provided for different TTI lengths, then power control precision is improved, but control information overhead increases
Solution Approach 1:
The patent makes the TPC command field universal by allowing it to serve different functions depending on the TTI length configuration. The same DCI structure can carry TPC commands for both short TTI and long TTI transmissions, and the interpretation of these commands adapts based on the active TTI length, reducing the need for separate dedicated command structures
3Adaptability or versatility
If accumulated value-based power control operation is used, then power adjustment flexibility is improved, but power control state management complexity increases
Solution Approach 1:
The patent applies preliminary action by resetting the accumulated power control state to a known initial value (e.g., 0 dB) when transitioning between different TTI lengths or when receiving specific network commands. This ensures that power control accumulation starts from a defined state, preventing error propagation and simplifying state management across different operational modes
Data Source
AI summary
Disclosed is a method for determining transmit power in a wireless communication system according to one embodiment of the present invention. The method, which is performed by a terminal, comprises the steps of: receiving a semi-persistent scheduling (SPS) setting of a short transmission time interval (sTTI); receiving control information for SPS-related transmit power control according to the received setting; and determining an SPS-related transmit power by using a transmit power control (TPC) command included in the received control information, wherein the control information may include a TPC command for each of a plurality of TTI lengths, which includes an SPS-related TPC command of the sTTI.