Terminal Equipment Power Control for PRACH and SRS Overflow
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Solution Overview
Problem
In LTE-A systems, particularly in Rel-11, the terminal equipment faces challenges in managing transmission power when transmitting PRACH and SRS signals simultaneously, or when transmitting PRACH and other physical uplink channel signals in the same subframe, as the total power exceeds the configured maximum output power, leading to potential signal overflow.
Innovation Solution
The terminal equipment employs a power control method that involves dropping SRS signals or puncturing PRACH signals in secondary serving cells within the same OFDM symbol, and adjusts transmission powers based on predefined priority orders for PRACH and physical uplink channel signals to ensure total power remains within the maximum output capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the terminal equipment transmits multiple uplink signals (PUSCH, PUCCH, PRACH, SRS) simultaneously, then the communication functionality and signal diversity are improved, but the total transmission power exceeds the configured maximum output power PCMAX
Solution Approach 1:
The patent dynamically adjusts transmission parameters including power allocation, time scheduling, and frequency resource distribution based on the actual transmission needs and power availability, transforming the fixed power constraint into a flexible parameter that adapts to different transmission scenarios
Solution Approach 2:
The patent implements dynamic power control mechanisms where the terminal equipment continuously monitors its power state and adjusts transmission parameters in real-time, transitioning from static power allocation to dynamic adaptation based on current communication requirements and power constraints
2Adaptability or versatility
If the terminal equipment transmits PRACH and SRS signals in the same OFDM symbol, then the random access and channel sounding functionality are improved, but the total transmission power exceeds PCMAX causing signal overflow
Solution Approach 1:
The patent performs preliminary power calculation and resource scheduling before actual signal transmission, determining the power allocation for PRACH and SRS signals in advance to ensure that their combined power does not exceed PCMAX, thereby preventing signal overflow before it occurs
Solution Approach 2:
The patent implements preemptive power control measures that anticipate potential power overflow scenarios and apply corrective adjustments before transmission, such as pre-calculating power headroom and adjusting signal parameters to prevent exceeding maximum power limits
3Adaptability or versatility
If the terminal equipment transmits PRACH and physical uplink channel signals in the same subframe, then the access and data transmission functionality are improved, but the total transmission power exceeds PCMAX
Solution Approach 1:
The patent segments the total transmission power into distinct allocations for different signal types (PRACH, PUSCH, PUCCH, SRS) within the same subframe, assigning priority levels and power portions to each signal type to ensure the sum does not exceed PCMAX while maintaining functional requirements
Solution Approach 2:
The patent applies different power control strategies and priority rules to different signal types locally, allowing PRACH to receive higher priority power allocation when needed while adjusting power for other signals accordingly, creating localized power optimization for each signal type based on its specific requirements
Data Source
AI summary
A user equipment includes: a transmitter configured to transmit uplink signals; and a processor circuit coupled with the transmitter, the processor circuit configured to: drop a Sounding Reference Signal (SRS) transmission when a total transmission power exceeds maximum output power of the user equipment and the user equipment needs to transmit a Physical Random Access Channel (PRACH) signal in a secondary serving cell in parallel with the SRS transmission in a symbol on a subframe of a different serving cell; and adjust transmission power of a Physical Uplink Shared Channel (PUSCH) signal until an adjusted total transmission power is less than or equal to the maximum output power of the user equipment when the user equipment needs to transmit a PRACH signal in a secondary serving cell in parallel with a PUSCH signal in a different serving cell within a symbol.