Uplink Power Control Accumulation for LTE User Equipment
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Solution Overview
Problem
In radio communication systems, particularly in LTE networks, there is a challenge in determining when to accumulate Transmit Power Control (TPC) commands when a user equipment (UE) does not have an uplink transmission scheduled, making it uncertain how to handle TPC commands without knowing the maximum or minimum transmit power values for PUSCH, PUCCH, or SRS transmissions.
Innovation Solution
A method and device for a UE to accumulate TPC commands based on whether it has reached a maximum or minimum transmit power in a reference format for PUSCH, SRS, or PUCCH transmissions, even when no uplink transmission is scheduled, allowing for flexible and efficient power control without requiring dynamic tracking of transmission status by the base station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the UE accumulates TPC commands only when uplink transmission is scheduled, then the base station does not need to track transmission status dynamically, but the UE cannot receive and accumulate TPC commands when no transmission is scheduled, reducing power control flexibility
Solution Approach 1:
The UE performs preliminary determination of maximum and minimum transmit power values for PUSCH, PUCCH, or SRS transmissions before receiving TPC commands. This preliminary action enables the UE to accumulate TPC commands even when no uplink transmission is currently scheduled, as the power boundaries are already established in advance, thus improving power control adaptability without increasing base station complexity
Solution Approach 2:
The UE autonomously determines whether to accumulate a received TPC command by comparing it against its own pre-determined maximum and minimum transmit power values, without requiring the base station to track or communicate transmission status. This self-service mechanism resolves the contradiction by enabling flexible power control at the UE side while keeping the base station operation simple
2Measurement precision
If the UE determines maximum and minimum transmit power values dynamically based on actual transmission status, then power control is accurate, but the implementation complexity increases due to dynamic tracking requirements
Solution Approach 1:
The maximum and minimum transmit power values are determined in advance based on pre-defined reference formats for PUSCH, PUCCH, or SRS transmissions, rather than being calculated dynamically during each transmission. This preliminary determination maintains power control precision by establishing clear boundaries while significantly reducing implementation complexity by eliminating the need for continuous dynamic tracking
Solution Approach 2:
The patent changes the approach from dynamic parameter calculation to using pre-defined reference parameters. By basing power determination on reference formats with predetermined maximum and minimum values, the system maintains measurement precision while reducing device complexity through parameter standardization
3Device complexity
If the UE uses pre-defined reference formats to determine power values, then implementation is simpler, but power control may be less accurate for actual transmission conditions
Solution Approach 1:
The patent applies different reference formats locally to different uplink channel types (PUSCH, PUCCH, SRS), where each channel has its own specific reference format with appropriate maximum and minimum power values. This local quality approach maintains implementation simplicity through standardized references while improving power control accuracy by using channel-specific reference characteristics rather than a single generic reference
Data Source
AI summary
The disclosure relates to methods and devices for performing uplink power control in a radio communication system. An example method comprises a step of receiving, at a user equipment (UE) a transmit power control (TPC) command. The method also comprises, if the UE does not have an uplink transmission scheduled for a subframe associated with the TPC command, a step of accumulating, by the UE, the TPC command with previously received TPC commands based on whether the UE has reached a maximum transmit power or a minimum transmit power in a reference format for a Physical Uplink Shared Channel (PUSCH), Sounding Reference Signal (SRS) or Physical Uplink Control Channel (PUCCH) transmission. Thus the UE is enabled to receive TPC commands while the UE is not transmitting anything in the uplink.