Adaptive Power Control for Shortened TTI Patterns
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Solution Overview
Problem
In LTE systems, the current specifications do not provide a clear method for estimating configured output power for consecutive Transmission Time Intervals (TTIs) in shortened TTI patterns, leading to inefficiencies in power management and potential interference issues due to unchanged slot sizes and overlapping TTI configurations.
Innovation Solution
A method for determining a single maximum output power parameter for consecutive TTIs based on their specific configurations, allowing for accurate power management and transmission across non-overlapping or overlapping TTIs, thereby addressing the inefficiencies in power estimation and interference mitigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If slot size remains unchanged in shortened TTI patterns, then TTI duration is reduced for lower latency, but power management becomes inconsistent and interference issues arise
Solution Approach 1:
The patent applies dynamics by making the power management parameters adaptive to the shortened TTI duration. The closed-loop power control adjustment is scaled based on the ratio of shortened TTI to normal TTI duration, allowing the system to dynamically adjust power control behavior according to the actual transmission time interval, thereby maintaining reliability despite reduced TTI duration.
Solution Approach 2:
The patent changes the parameter of power control adjustment by introducing a scaling factor that modifies the closed-loop power control TPC command based on the TTI duration ratio. This parameter change allows the power management to be consistent with the shortened TTI pattern while preventing interference issues that would arise from using fixed power control parameters designed for normal TTI durations.
2Speed
If closed-loop power control TPC command is applied without adjustment, then power control responsiveness is maintained, but interference increases due to mismatched power levels in shortened TTIs
Solution Approach 1:
The patent changes the TPC command parameter by scaling it with the ratio of shortened TTI to normal TTI duration. This ensures that the power control responsiveness is maintained through closed-loop control while the actual power adjustment magnitude is appropriately reduced for the shorter transmission interval, preventing excessive power changes that would cause interference.
Solution Approach 2:
The patent makes the TPC command dynamic by applying a scaling factor that adapts to the specific shortened TTI duration. This dynamic adjustment ensures that power control remains responsive to channel conditions while the magnitude of power adjustments is appropriately scaled to the shorter time interval, avoiding interference caused by overly aggressive power changes.
3Reliability
If power control parameters are optimized for normal TTI, then link quality is maintained, but system efficiency decreases in shortened TTI patterns
Solution Approach 1:
The patent applies dynamics by making the power control parameters adaptive to the shortened TTI pattern. The closed-loop power control adjustment is scaled based on the ratio of shortened TTI to normal TTI duration, allowing the system to maintain link quality through proper power management while improving system efficiency by enabling faster transmission cycles and better resource utilization in the shortened TTI framework.
Solution Approach 2:
The patent changes the power control parameters by introducing a scaling factor that modifies the closed-loop adjustment magnitude according to the TTI duration ratio. This parameter change allows the system to maintain link quality by preserving the essential power control functionality while optimizing system efficiency through appropriate power levels suited for shortened transmission intervals.
Data Source
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AI summary
A network node is provided. The network node includes circuitry configured to determine a Transmission Time Interval, TTI, configuration, the TTI configuration including a first TTI for operating a first signal between a first cell on a first carrier and a wireless device, and a second TTI for operating a second signal between the first cell on the first carrier and the wireless device, the TTI configuration including one of: the first TTI adjacent to the second TTI which do not overlap with each other in time; and the first TTI adjacent to the second TTI which at least partly overlap with each other in time, and configured to receive the first signal in the first TTI and the second signal in the second TTI, the first TTI and second TTI having been transmitted based on a maximum output power parameter that is based on the TTI configuration.