Separate Transmit Power Parameters for SRS in LTE
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Solution Overview
Problem
Conventional methods for transmit power control (TPC) of periodic and aperiodic SRS in LTE systems result in identical transmit powers for both, leading to inefficient power management, with aperiodic SRS transmit power potentially exceeding the maximum allowed value, compromising channel measurement accuracy.
Innovation Solution
Implementing separate transmit power parameters for periodic and aperiodic SRS, allowing the base station to set and notify these parameters based on the number of PRBs and specific transmission requirements, enabling flexible TPC according to priority and bandwidth, and applying these parameters to each transmission antenna port.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single TPC parameter is used for both periodic and aperiodic SRS, then the system complexity is reduced, but the transmit power control accuracy deteriorates and aperiodic SRS power may exceed maximum allowed values
Solution Approach 1:
The patent divides the single TPC parameter into separate parameters for periodic SRS and aperiodic SRS. Specifically, it introduces different offset parameters (e.g., srs-Offset for periodic SRS and aperiodicSrs-Offset for aperiodic SRS) and different path loss compensation coefficients (alpha for periodic and beta for aperiodic), allowing independent power control for each SRS type and preventing power overflow.
Solution Approach 2:
The patent applies different TPC parameter configurations to different SRS types based on their specific requirements. Periodic SRS uses one set of parameters optimized for regular channel sounding, while aperiodic SRS uses another set optimized for on-demand measurements, ensuring each gets appropriate power control without affecting the other.
2Measurement precision
If transmit power is increased to improve channel measurement accuracy, then measurement precision improves, but power consumption increases and interference to other cells increases
Solution Approach 1:
The patent implements dynamic TPC where the base station adjusts different parameters (offset values, alpha coefficients, beta coefficients) based on real-time channel conditions, mobile station capabilities, and network load. This allows the system to optimize the balance between measurement accuracy and power consumption adaptively rather than using fixed power levels.
Solution Approach 2:
The patent changes multiple TPC parameters simultaneously including offset values, path loss compensation coefficients (alpha and beta), and maximum power limits. By adjusting these parameters dynamically, the system can achieve accurate channel measurements while controlling power consumption and interference levels according to network conditions.
3Area of stationary object
If aperiodic SRS bandwidth is increased to improve channel sounding coverage, then measurement coverage improves, but transmit power requirements increase significantly
Solution Approach 1:
The patent introduces a dedicated beta coefficient for aperiodic SRS that differs from the alpha coefficient used for periodic SRS. This allows the base station to configure appropriate path loss compensation for wideband aperiodic SRS transmissions, managing the power requirements when large bandwidths are allocated for comprehensive channel sounding.
Data Source
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AI summary
Optimal transmit power control is performed on each of a periodic SRS and an aperiodic SRS. In a radio communication system in which a mobile station apparatus 1 transmits a first reference signal or a second reference signal to a base station apparatus 3, the base station apparatus 3 notifies the mobile station apparatus 1 of a first parameter used for setting of a transmit power for transmission of the first reference signal, and a second parameter used for setting of a transmit power for transmission of the second reference signal, and the mobile station apparatus 1 sets the transmit power for transmission of the first reference signal using the first parameter, while setting the transmit power for transmission of the second reference signal using the second parameter.