Transmit Power Difference Compensation for TDD Channel Estimation
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Solution Overview
Problem
Current wireless communication systems face challenges in accurate channel estimation due to unequal transmit power between antennas, particularly in Time Division Duplex (TDD) bands, which affects downlink capacity and precoding accuracy.
Innovation Solution
A method and apparatus that utilize a transceiver with a power amplifier to determine and transmit transmit power difference information between antenna ports, allowing for compensation of unequal SRS transmit power in reciprocity-based channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If SRS transmission is used for channel estimation, then the UE does not need to signal the precoder to the gNB and the gNB precoder is not limited to a pre-defined codebook, but unequal transmit power between antennas degrades channel estimation accuracy
Solution Approach 1:
The patent changes the power parameter of SRS transmission by applying different power compensation values to different antenna ports. The gNB determines power difference information between antenna ports and applies power compensation to equalize the effective transmit power, thereby resolving the measurement precision degradation caused by unequal antenna transmit power while maintaining the adaptability benefits of SRS-based channel estimation.
2Device complexity
If different antenna ports share a common power amplifier, then device complexity is reduced, but power loss varies between antenna ports causing unequal transmit power
Solution Approach 1:
The patent applies local quality by introducing antenna-port-specific power compensation values that account for the different power losses in each antenna port's signal path. Each antenna port receives a tailored power adjustment based on its specific losses from the common power amplifier, thereby equalizing the effective transmit power across ports while maintaining the simplicity of the shared amplifier architecture.
3Adaptability or versatility
If receive-only antenna ports are used for SRS transmission, then antenna utilization is improved, but power loss between PA and antenna port degrades transmit power equality
Solution Approach 1:
The patent applies preliminary action by pre-determining the power difference information for each antenna port before SRS transmission. The gNB calculates the power compensation values in advance based on the known power loss characteristics of each antenna port's connection to the power amplifier, and applies these compensations to equalize the effective transmit power, thereby enabling fair utilization of receive-only antenna ports for SRS transmission.
Data Source
AI summary
Reference symbols can be received. A first received power of the reference symbols on a first antenna port can be measured. A second received power of the reference symbols on a second antenna port that is coupled to and uses the same transmit power amplifier as the first antenna port can be measured. A received power difference can be determined based on a relationship between the second received power and the first received power. A value of the received power difference can be transmitted.