SRS Power Control for Heterogeneous Network Measurement
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Solution Overview
Problem
In heterogeneous network environments, the macro eNB struggles to accurately measure channel quality between the pico UE and the macro eNB due to the pico UE transmitting SRS with power based on the path loss of the pico eNB, leading to lower reception levels at the macro eNB and increased measurement errors.
Innovation Solution
The system introduces power-boosted SRS transmission subframes, where the pico UE increases its SRS transmission power specifically for subframes received by the macro eNB, ensuring sufficient signal levels and reducing measurement errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pico UE transmits SRS with power based on the path loss of the pico eNB, then the reception level at the pico eNB is sufficient, but the reception level at the macro eNB is low leading to measurement errors
Solution Approach 1:
The patent applies local quality by configuring different SRS transmission power levels for different reception scenarios. Specifically, the base station configures a first SRS transmission power level when the macro eNB is the reception target, and a second (lower) power level when the pico eNB is the reception target. This allows the system to optimize reception quality at each specific location without requiring the UE to continuously transmit at maximum power to all locations.
Solution Approach 2:
The patent implements dynamics by making the SRS transmission power configurable and switchable based on the intended reception target. The base station dynamically adjusts the SRS power level according to whether the macro eNB or pico eNB should receive the signal, allowing the system to adapt to changing network conditions and CoMP requirements without hardware modifications.
2Measurement precision
If the pico UE increases SRS transmission power for macro eNB reception, then the channel quality measurement accuracy at macro eNB improves, but power consumption and interference to other cells increase
Solution Approach 1:
The patent applies partial action by having the UE transmit SRS at increased power only when and where needed (when the macro eNB is the reception target), rather than continuously at maximum power. The base station configures appropriate power levels based on the specific CoMP scenario, ensuring sufficient signal strength for accurate measurement without unnecessary excessive power transmission that would waste energy and cause interference.
3Measurement precision
If the pico UE increases SRS transmission power for macro eNB reception, then the channel quality measurement accuracy at macro eNB improves, but interference to other cells increases
Solution Approach 1:
The patent applies local quality by configuring different SRS transmission power levels for different reception scenarios. Specifically, the base station configures a first SRS transmission power level when the macro eNB is the reception target, and a second (lower) power level when the pico eNB is the reception target. This allows the system to optimize reception quality at each specific location without requiring the UE to continuously transmit at maximum power to all locations.
Data Source
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AI summary
Provided is a terminal apparatus in which, a transmission control unit (204) controls the transmission power of a sounding reference signal (SRS) by use of an offset value relative to the transmission power of a data signal, and a transmission unit (206) transmits the SRS by use of the transmission power as controlled. If a subframe to be used for transmitting the SRS is a predetermined subframe, the transmission control unit (204) uses a first offset value to control the transmission power of the SRS. Otherwise, the transmission control unit (204) uses a second offset value to control the transmission power of the SRS. The second offset value is an offset value that has been established so as to be transmitted to the serving cell of the terminal (200), and the first offset value is greater than the second offset value.