Terminal Uplink Power Allocation for Short TTI Latency
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Solution Overview
Problem
When transmitting uplink signals in multiple transmission time intervals (TTIs) with different lengths, the available transmission power may not be sufficient, leading to power allocation imbalances and potential delays in transmitting packets with higher priority due to insufficient power allocation.
Innovation Solution
A terminal is configured with a transmission-power determining section that dynamically adjusts the transmission power for uplink signals in different TTIs. This involves maintaining constant transmission power for reference signals and long TTIs while allocating power to shorter TTIs only in subsequent intervals, ensuring that higher priority packets are transmitted without delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If multiple TTI lengths are supported simultaneously to reduce latency for delay-critical packets, then the frequency of CQI reporting increases and latency is reduced, but transmission power becomes insufficient when the maximum transmission power is not enough to support both long TTI and short TTI uplink signals
Solution Approach 1:
The patent changes the transmission power parameter dynamically based on the TTI type. For long TTI uplink signals, normal transmission power is used, while for short TTI uplink signals that occur during long TTI transmission, the transmission power is set to zero to avoid power insufficiency. This parameter change resolves the contradiction by adapting power allocation to the specific TTI context.
Solution Approach 2:
The patent introduces dynamic power allocation where the transmission power for short TTI uplink signals is adjusted based on whether they occur during long TTI transmission intervals. The power allocation is not static but changes according to the timing relationship between different TTI types, allowing the system to adapt to varying power availability conditions.
2Loss of time
If transmission power is allocated to short TTI uplink signals during long TTI transmission, then latency for delay-critical packets is reduced, but the transmission power for long TTI uplink signals decreases causing power allocation imbalance
Solution Approach 1:
The patent applies local quality by differentiating power allocation based on the specific time interval and TTI type. Instead of uniform power allocation, the system assigns different power levels to different segments of transmission: full power for long TTI signals and zero power for short TTI signals occurring during long TTI transmission. This localized differentiation resolves the power allocation balance issue.
3Productivity
If the transmission power for long TTI uplink signals is reduced to allocate power to short TTI uplink signals, then short TTI packets can be transmitted, but the transmission quality of long TTI signals deteriorates due to constant power requirement for reference signals
Solution Approach 1:
The patent extracts the short TTI uplink signal transmission from the long TTI transmission by setting its power to zero when they overlap. This separation prevents interference and power allocation conflicts, allowing long TTI signals to maintain their required transmission quality while short TTI signals are transmitted in separate time intervals with dedicated power allocation.
Data Source
AI summary
A terminal includes circuitry and a transmitter. The circuitry, in operation, determines a first transmission power for a first uplink signal and a second transmission power for a second uplink signal by prioritizing allocation of a transmission power to the second transmission power for the second uplink signal, responsive to, in a first transmission time interval (TTI) where the first uplink signal is transmitted, the second uplink signal being transmitted in a second TTI that is shorter than the first TTI. The transmitter, in operation, transmits the first uplink signal with the determined first transmission power and transmits the second uplink signal with the determined second transmission power.